Search

Pulp and paper are gradually transforming from a traditional industry into a new green strategic industry. In parallel, cellulose-derived transparent paper is gaining ground for the development of advanced functional materials for light management with eco-friendly, high performance, and multifunctionality. This review focuses on methods and processes for the preparation of cellulose-derived transparent papers, highlighting the characterization of raw materials linked to responses to different properties, such as optical and mechanical properties. The applications in electronic devices, energy conversion and storage, and eco-friendly packaging are also highlighted with the objective to showcase the untapped potential of cellulose-derived transparent paper, challenging the prevailing notion that paper is merely a daily life product. Finally, the challenges and propose future directions for the development of cellulose-derived transparent paper are identified. [Display omitted] [ABSTRACT FROM AUTHOR]

A range of energy fuels (ethanol, char, oil/wax and gas) was produced from fibre waste contaminated with plastic through the application of a fermentation-pyrolysis route. The fibre component was first converted to ethanol by simultaneous saccharification and fermentation (SSF), achieving an ethanol concentration of 39.8 g/L. The residue, enriched in lignin and plastics, was subjected to fast pyrolysis at temperatures between 350 and 550 °C. A wax product with a higher heating value (HHV) higher than 28 MJ/kg was obtained for temperatures higher than 450 °C, while values lower than 15 MJ/kg were observed for the oils produced from the untreated waste stream. Pyrolysis at 550 °C produced a wax with an HHV as high as 32.1 MJ/kg, where 51.8% of the energy content of the fermentation residue was transferred. The attractive energy contents of the pyrolysis products were enabled by oxygen removal from the feedstock during fermentation to ethanol. [ABSTRACT FROM AUTHOR]

This work examines the feasibility of co-gasification of sewage sludge and paper-mill sludge in a commercial scale plant and its application for sludge-to-energy conversion. The results indicated that the thermal reaction activity is increased with an increase in the amount of sewage sludge. This is due to the sewage sludge contains less fixed carbon content could decrease the activation energy, resulting in a thermal reaction is significantly enhanced. The synthetic gas (syngas) composition, that includes H 2 and CO, ranged from percentages of 2.59%–4.13% and 3.2%–6.91%, respectively. The heating value of the produced gas ranged from 1.67 MJ/Nm 3 to 2.56 MJ/Nm 3 , which was coupled with cold gas efficiency (CGE) that ranged from 46.6% to 77%. In the case of two tons of wet tested sludge with 67% moisture content, it could produce one ton of dry tested sludge with 30% moisture content after a drying process, and produce approximately 2.2 tons of syngas in gasification. After using a boiler and heat exchanger for energy recovery, it is possible to recover 4.46 tons of steam. This steam could provide energy for the dryer, and constitutes a positive sum on the energy balance in a commercial scale gasification plant. [ABSTRACT FROM AUTHOR]

Efficient body heat harvesting with paper-based thermoelectric generator. [Display omitted] • Using paper as a flexible, lightweight, and biodegradable substrate for TEGs. • An easy, energy-efficient fabrication process suitable for large-scale production. • Maximum V oc and P max achieved were ∼42.60 mV and ∼10.65 nW at a Δ T of 30 °C. • Body attached PTG produces an output voltage of 11.95 mV and output power of 1.5 nW. • Effective low-grade heat harvesting from body, improving energy efficiency. The study presents the fabrication and characterization of paper-based thermoelectric generators (PTGs) using p -type Bi 0.5 Sb 1.5 Te 3 (BST) and n -type Bi 2 Te 2.7 Se 0.3 (BTS) thermoelectric (TE) materials, deposited via a novel cotton swab powder deposition technique. This method eliminates the need for complex equipment or high-temperature processes, reducing fabrication complexity and enabling large-scale production. The key advancements of this method are its simplicity, cost-effectiveness, and practical applicability, ensuring uniform coating and good material adherence to the paper substrate. The PTGs, consisting of five p - n pairs interconnected with various materials, were laminated for enhanced stability and humidity protection. Experimental measurements under temperature gradients(ΔT s) of 5–30 °C revealed an optimal configuration achieving an open-circuit voltage(V oc) of 42.60 mV, internal resistance(R int) of 42.50kΩ, short-circuit current(I sc) of 1.00µA, and maximum power output(P max) of 10.65nW for the carbon paste/copper sheet interconnected PTG at ΔT of 30 °C. The obtained normalized power density is 5.68nWcm-2K-1pair-1, which is one of the best among the reported Bi 2 Te 3 -based PTGs. A preliminary demonstration on an arm showed the PTG generating an 11.95 mV output voltage in hot weather conditions (ΔT ≈ 8 °C), effectively harnessing body heat for wearable electronics. This work highlights a simple, cost-effective, and scalable method for fabricating PTGs for sustainable energy harvesting in low-power wearable applications. Future efforts will focus on optimizing materials, fabrication techniques, and novel designs to enhance efficiency and scalability. [ABSTRACT FROM AUTHOR]

Sheet-like transition metal sulfides have promising applications in photocatalysis and energy conversion. This study provides a petal-like Cu 2 WS x nanosheet structure supported on carbon paper (CP) synthesized by a simple one-step solvothermal method. Cu 2 WS x microstructures with different morphologies were synthesized by solvothermal vulcanization of thioacetamide (TAA) at different concentrations. The Cu 2 WS x /CP was used as the counter electrode of DSSCs and compared with the Pt FTO electrode. It was proved that Cu 2 WS x -7 M/CP had the best electrocatalytic performance and obtained 9.01% photoelectric conversion efficiency. The different sulfide concentration changes the morphology of Cu 2 WS x and continuously affects the specific surface area and catalytic activity of the material. The better electrochemical performance shows that Cu 2 WS x /CP is expected to become a substitute for expensive Pt CE materials in dye-sensitized solar cells (DSSCs). [Display omitted] • One-step solvothermal method for the growth of petal-like Cu 2 WS x on carbon paper. • The effect of sulfide concentration on Cu2WSx was explored for the first time by TAA. • For the first time, Cu 2 WS x /CP was used as a counter electrode for DSSCs. • At a sulfide concentration of 7 M, Cu 2 WS x /CP exhibited a value of 9.01% PCE (Pt 7.67%). [ABSTRACT FROM AUTHOR]

Paper sludge samples collected from recycling mills exhibited high ash content in the range of 54.59%–65.50% and glucose concentrations between 21.97% and 31.11%. Washing the sludge reduced the total ash content to between 10.7% and 19.31% and increased the concentration of glucose, xylose and lignin. Samples were screened for ethanol production and fed-batch simultaneous saccharification and fermentation (SSF) was optimised for the washed samples that resulted in highest and lowest ethanol concentrations. Maximum ethanol concentrations of 57.31 g/L and 47.72 g/L (94.07% and 85.34% of the maximum theoretical yield, respectively) was predicted for high and low fermentative potential samples, respectively, and was experimentally achieved with 1% deviation. A generic set of process conditions were established for the conversion of high ash-containing paper sludge to ethanol. Techno-economic analysis based on three different revenue scenarios, together with Monte Carlo analysis revealed 95% probability of achieving IRR values in excess of 25% at a paper sludge feed rate of 15 t/d. Feed rates of 30 t/d and 50 t/d exhibited a cumulative probability of 100%. This study presents the technical feasibility and economic viability of paper mills expansion towards bioethanol production from paper sludge. [ABSTRACT FROM AUTHOR]

Pyrolysis of paper mill sludge (PMS) was conducted to produce syngas (H 2 and CO) and fabricate magnetic biochar (PMS biochar) for use as an adsorbent for As(V). The enhanced generation of CO was observed in the CO 2 atmosphere due to reactions triggered by CO 2 . Particularly, the generation of syngas from pyrolysis of PMS in CO 2 (9.6 mol% at 720 °C) was superior to the cases of pyrolysis of acid-washed PMS ( i.e. , minerals-eliminated PMS) in CO 2 (2.9 mol% at 720 °C), which evidences catalytic effects attributed by Fe and Ca species contained in PMS. Based on the results of X-ray diffraction (XRD), pyrolysis of PMS in CO 2 led to the conversion of Fe species into magnetite (Fe 3 O 4 ) solid phase that imparted the magnetic property to the biochar (saturation magnetization: 28.4 emu g −1 ). The PMS biochar exhibited high As(V) adsorption capacity of 34.1 mg g −1 in a given condition, which could be attributed to the great adsorption affinity of Fe 3 O 4 /CaCO 3 mixture toward As(V). The integrated approach for the utilization of PMS could satisfy growing demand for renewable energy and environmental sustainability. [ABSTRACT FROM AUTHOR]

Water splitting associated with the conversion and storage of renewable energy is considered to be the most significant strategy to create hydrogen. Herein, an efficient self-supported electrode was developed by in-situ growth of interlayer expanded lamellar cobalt diselenide (CoSe 2 ) nanosheets (NS) on carbon paper (CP) substrate (CoSe 2 NS@CP). The analyses of TEM, SEM and XRD confirmed that the CP is homogeneously coated by few stacking layers of interlayer expanded lamellar structured CoSe 2 . This rationally designed nanostructure can provide more active sites for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The bifunctional electrode exhibits high electrocatalytic performance with −128 mV vs. RHE onset potential for the HER in 0.5 mol dm −3 H 2 SO 4 and +1521 mV vs. RHE for the OER in 1.0 mol dm −3 KOH. Besides, small electrolysis potentials of −201.1 mV vs. RHE and +1636 mV vs. RHE are needed to drive the HER and OER at current density of 100 mA cm −2 . Finally, a small overall cell voltage ( ca. +1.75 V) was used to drive the water splitting reaction in 1.0 mol dm −3 KOH. The CoSe 2 NS@CP electrode showed both excellent catalytic activity with overall current density of 100 mA cm −2 at 2.13 V and tremendous durability with negligible decrease in potential at a constant current of 20 mA cm −2 for more than 30 hours. Thus this rationally designed electrode material can be readily applied for large-scale water splitting process. [ABSTRACT FROM AUTHOR]

In an era of modern smart technology, flexible electrodes are of great interest for different energy conversion as well as energy storage applications like solar cells, all solid-state batteries, and supercapacitors. Flexible metal oxide-based paper electrodes are advantageous in comparison to conventional electrodes due to their economical synthesis, biocompatibility, and environment-friendly characteristics. However, the electrical conductivity of paper electrodes is limited because of the insulating nature of natural fibers employed as a binder for the flexible matrix of metal oxides. The current study is an attempt to tune the electrical properties of lignocelluloses (natural fibers) and titanium dioxide (TiO 2) based paper electrodes by facile electrodeposition technique. The crystalline parts (e.g., TiO 2 , Ag, and Au) of the prepared composite sheets were characterized by XRD analysis while the surface morphology was studied by SEM. FTIR was used to characterize the organic matter in LC fibers by identifying various molecular stretching and vibrational modes of C, H, and O-containing molecules. Electric permittivity was measured as a function of electric field frequency at room temperature which revealed the value of 23. 5 (at 1 kHz) for the sample LC/TiO 2 /Ag 9000s indicating the best charge storing capability of the sample. Impedance analysis was employed to identify various charge carrier mechanisms active in the sheets. It was found through impedance analysis that there is an active diffusion-controlled impedance mechanism of Au-coated samples causing an increased conductivity via the ionic diffusion. This diffusion-controlled conduction was modeled by the Warburg element. The enhanced conductivity due to ionic diffusion makes these samples more useful as electrodes. Cyclic voltammetry (CV) measurements of the electrodeposited samples established the increase in conductive properties and efficient kinetics of LC/TiO 2 paper sheets. The current study suggests that Ag and Au-coated paper electrodes can be potential candidates for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Pyrolysis is a promising technology for the production of marketable energy products from waste mixtures, as it decomposes heterogeneous material into homogenous fuel products. This research assessed the ability of slow pyrolysis to convert three waste streams, composed of fibre residues contaminated with different plastic mixtures, into char and tarry phase products at three different temperatures (300, 425 and 550 °C). The products were characterised in terms of mass yield, higher heating value (HHV) and gross energy conversion (EC). Significant amounts of hydrocarbon plastics in the feed materials increased the calorific values of the char (up to 32.9 MJ/kg) and tarry phase (up to 42.8 MJ/kg) products, comparable to high volatile bituminous A coal and diesel respectively. For all three waste streams converted at 300 °C, the majority of the energy in the feedstock was recovered in the char product (>80%), while deoxygenation of fibre component resulted in char with increased calorific value (up to 31.6 MJ/kg) being produced. Pyrolysis at 425 °C for two of the waste streams containing significant amounts of plastic produced both a valuable char and tarry phase, which resulted in an EC greater than 74%. Full conversion of plastic at 550 °C increased the tarry phase yield but dramatically decreased the char HHV. The influence of temperature on product yield and HHV was discussed based on the pyrolysis mechanisms and in relation to the plastic composition of the waste streams. [ABSTRACT FROM AUTHOR]

Abstract: The pulp and paper industry both uses and produces large amounts of energy and rising fuel prices bring along significant challenges to the sector. Several strategies can be applied in order to remain competitive e.g. an increase in energy efficiency, a switch in fuel and/or a novel energy conversion technology. In this study, we investigate if improved energy conversion strategies can reduce energy costs, primary energy use and CO2 emissions of paper mills within different European countries (The Netherlands, Poland and Sweden). Our results show that differences in history and availability of resources has led to different conversion strategies in the three countries. We found that a natural gas combined cycle, which is largely implemented in The Netherlands due to long term domestic availability of natural gas, has the lowest primary energy demand. Due to a long history of low electricity prices, CHP has not been common in Sweden. Many Swedish mills use biomass as an energy source and due to low CO2 emissions of the national grid the CO2 emission profile of the Swedish paper industry is very low. Our results imply that future conversion routes for the Swedish paper and board industry are again wood based; in case of increasing electricity prices these would be biomass gasification based CHP solutions. With a reduction of 800kg CO2/ton paper on average, a switch from coal to biomass would reduce CO2 emissions in the Polish pulp and paper industry with approximately 0.6Mton/year. A carbon price of 20–25€/ton would, according to our results, be enough to provoke this switch. Due to the high share of natural gas, the CO2 emission reduction potential of the Dutch paper industry (1.5Mton/year) is even larger than in Poland. Due to high biomass prices and relative low CO2 emission profile of natural gas, a carbon prices of more than 60€/ton CO2 would be needed to provoke a switch in The Netherlands. Provided with few alternatives, the most effective strategy in The Netherlands would be an increase in energy efficiency. [Copyright &y& Elsevier]

The pulp and paper industry faces several challenges linked to climate and environmental impact, resource efficiency, rising energy prices, increased competition for biomass resources, and declining demand for traditional printed paper products. However, these challenges also offer strategic opportunities for the industry to develop into a competitive, resource-efficient, and low-carbon industry in line with a biobased economy. Against this background, this paper aims to analyse current energy strategies in the pulp and paper industry in Sweden. Specifically, the paper analyses how companies combine continuous process efficiency to reduce energy costs with activities that could be developed into new energy-related products to increase revenue. Most of the analysed companies work to various degrees with both these strategies, employing methods that include improving energy efficiency, energy security, and energy conversion, as well as developing a wide range of biobased energy products. However, our study indicates that there is an untapped potential associated with energy product development, and we conclude that energy efficiency measures can free up resources, enabling the development of new energy products. Finally, several potential managerial outcomes and implications are outlined. • The paper analyses the energy strategies in the pulp and paper industry in Sweden. • Energy strategies focus both to improve energy efficiency and develop new energy-products. • The companies' energy strategies combined exploitation and exploration. • A number of managerial implications are presented. [ABSTRACT FROM AUTHOR]

The performance of vacuum, slow and fast pyrolysis processes to transfer energy from the paper waste sludge (PWS) to liquid and solid products was compared. Paper waste sludges with low and high ash content (8.5 and 46.7 wt.%) were converted under optimised conditions for temperature and pellet size to maximise both product yields and energy content. Comparison of the gross energy conversions, as a combination of the bio-oil/tarry phase and char (EC sum ), revealed that the fast pyrolysis performance was between 18.5% and 20.1% higher for the low ash PWS, and 18.4% and 36.5% higher for high ash PWS, when compared to the slow and vacuum pyrolysis processes respectively. For both PWSs, this finding was mainly attributed to higher production of condensable organic compounds and lower water yields during FP. The low ash PWS chars, fast pyrolysis bio-oils and vacuum pyrolysis tarry phase products had high calorific values (∼18–23 MJ kg −1 ) making them promising for energy applications. Considering the low calorific values of the chars from alternative pyrolysis processes (∼4–7 MJ kg −1 ), the high ash PWS should rather be converted to fast pyrolysis bio-oil to maximise the recovery of usable energy products. [ABSTRACT FROM AUTHOR]

A novel electrode consisting of 3D porous nickel‒cobalt‒copper sulfide dendritic structures is synthesized, in which, for the first time ternary Ni–Co–Cu foam is constructed through hydrogen bubble template and followed by sulfidization via a hydrothermal reaction in thiourea. The 3D, porous Ni–Co–Cu dendritic sulfide electrode exhibits a high specific capacitance of 1203.75 F g−1 (0.963 F cm−2) at current of 1.0 mA and excellent cycling stability, excellent ratability along with high cycle stability. An asymmetric supercapacitor (ASC) using dendritic sulfide structures and reduced electro-etched carbon fiber paper (RECF) as the positive and negative electrodes, respectively is developed. RECF is prepared through electrochemical oxidation process in acidic solution followed by electrochemical reduction, which exhibits a high areal capacitance of 695 mF cm−2 at current of 1.0 mA. The assembled device can be operating reversibly between 0 and 1.6 V and provides high specific capacitance of 178.5 mF cm−2 and an excellent cycling stability of 97.3% after 1000 cycles. This work exploits a pathway to construction of dendritic sulfides of quaternary metal foams that could be used for any flat metal substrate and open a new doorway to quaternary transition metal sulfides electrode materials in energy storage and conversion devices. • Novel quaternary Ni–Co–Cu sulfide dendritic electrode on nickel foil was successfully prepared by hydrothermal treatment. • High Specific capacitance of 1203.75 F g−1 (0.963 F cm−2) at a current of 1 mA was achieved. • The prepared quaternary Ni–Co–Cu sulfide dendritic electrode showed excellent ratability. • The reduced electro-etched carbon fiber paper is investigated as the binder-free negative electrode. • The asymmetric supercapacitor exhibits maximum operational potential window 1.6 V and areal capacitance of and 178.5 mF cm−2. [ABSTRACT FROM AUTHOR]

The economics of Recycled Paper Sludge conversion into ethanol was here assessed with emphasis on integrating a cellulase recycling system. Without cellulases recycling this process presented positive economic outputs (payback period of 7.85 years; 10.90 Million US$ of accumulated NPV) despite the modest ethanol titers. Recycling both free and solid-bound enzymes allowed considerable savings of enzyme but also an increase on annual costs (0.88%), resulting on a superior economic output: payback period decreased to 7.25 years; accumulated NPV increased to 14.44 Million US$. Recycling exclusively the liquid fraction enabled a clear costs reduction, however, also total ethanol decreased, attenuating the abovementioned benefits. Targeting higher ethanol concentrations, superior solids consistencies were also evaluated. Despite a costs reduction, total ethanol decreased due to a higher ethanol retention on the solid. A sensitivity analysis further revealed that the cost of enzymes and ultrafiltration membrane may be critical on enzyme recycling economic feasibility. [ABSTRACT FROM AUTHOR]

Designing highly efficient electrocatalysts for oxygen evolution reaction is important to meet the requirement of various renewable energy storage and conversion devices. Generally, the performance of OER catalysts can be significantly improved by synergistic action of the underlying conductive substrate. In this work, a commercial graphite paper was used as a facile substrate with catalytic activity. Graphite paper produced 10 mA cm −2 at an overpotential of 447 mV with a Tafel slope of 62 mV dec −1 . By depositing NiFe hydroxide or Mn oxide film onto the graphite paper, the electrode presented a superior activity for water oxidation, which was believed to be synergistically contributed by their available electrochemically active sites associated with the deposited film and the active substrate. High activities were also accompanied by remarkable durability at large current density levels. Our results illustrated a guideline to the design of inexpensive and highly active composite electrode for water oxidation. [ABSTRACT FROM AUTHOR]

Coconut husk was treated with pulp and paper industry wastewater for impregnating metal constituents present in it. The present work was focused on humidified air as an alternative to steam for generation of hydrogen-rich fuel gas in an updraft fixed-bed gasification column. A series of experiments were performed to see the effect of temperature, air/humidified air and CO 2 addition on gas yield and composition. Furthermore, some experiments were also conducted by varying impregnation temperature at the optimum condition to see the effect of impregnation temperature on gas yield and calorific value. The gross calorific value (GCV) of coconut husk C 53.84 H 77.80 O 43.99 N was estimated as 23.21 MJ/kg. The fuel gas production was found in the range from 0.68 to 2.89 Nm 3 /kg for native and from 0.83 to 3.13 Nm 3 /kg for impregnated coconut husk. The GCV of fuel gas yield was found to be maximum of 12578 kJ/Nm 3 for impregnated coconut husk at impregnation temperature of 105 °C, retrofitted with CO 2 in humidified air. The concentration of hydrogen was found maximum for impregnated coconut husk. The present gasification process not only provides feasibility of green energy but also renders to reduce the pressure of the environmental pollution created by the unutilized coconut husk. [ABSTRACT FROM AUTHOR]

Paper-based analytical devices are lightweight, inexpensively produced, effective, and easily disposable; allowing for their suitable implementation in resource-limited areas. They allow effective handling of quantitative analysis in a diverse range of areas, from standard healthcare and environmental monitoring to water quality monitoring. Nonetheless, such devices often require an energy source for their complex assays or readings, preventing their effective use. Most commonly, conventional batteries are integrated into the device to serve as an energy source. However, considering its non-environmentally friendly approach to energy generation and its difficulty of being effectively disposed, a search for a new power source has begun. In light of the newly found potential of cellulose-based entities in the energy field, attention has been drawn towards a supposedly unlikely material: paper. Considering the potentials of such technology, this manuscript aims to describe the benefits of current and future technologies of paper-based devices in the energy sector. Here, we discuss the role of paper as a main platform or part of energy storage and conversion devices such as fuel cells, lithium-ion batteries, and alkaline batteries thoroughly. [ABSTRACT FROM AUTHOR]

A general mathematical model is developed for electrochemical energy conversion in paper-based, capillary-driven, microfluidic flow cells. A two-dimensional version of the model is implemented to simulate a novel flow cell of this kind called PowerPAD. The methodology developed is validated against experimental data for this particular cell under both steady and unsteady modes of operation. It is shown that a 2D model can represent a 3D cell in unsteady flows provided that the Nernst-Planck equation is properly refined. The results are interpreted in terms of transient back-diffusion and crossover of the reactant species which are found to be the key factors controlling the electrochemical performance of this cell. The validated model is used to enhance the power output, runtime, and energy efficiency of this particular cell through altering its flow architecture and microstructure of electrodes and absorbent pad. The refined cell design is shown to roughly triple the power output and runtime of the device. The optimized design also outperforms the original design in terms of energy efficiency. The developed mathematical model, the fundamental understanding, and the proposed cell design may be utilized to develop new devices and concepts for capillary-based electrochemical systems, including biodegradable batteries, fuel cells, and electrolyzers. [Display omitted] • A dynamic mathematical model is developed for paper-based microfluidic flow cells. • A 2D model can represent a 3D cell subject to Nernst-Planck equation refinement. • The model reveals the unique working mechanism of imbibition and back-diffusion. • Crossover is identified as the key limiting factor for cell performance and runtime. • An optimized cell design is proposed with 3x performance improvement. [ABSTRACT FROM AUTHOR]

Graphene nanosheet devices have attracted significant interest in transistor and photodetector applications owing to photothermoelectric effects of graphene. However, their solar energy conversion ability has not been fully explored due to disadvantages of their transparency and zero gap semiconductor in this special field. Here, we propose the potential of graphene-carbon nanotube papers for energy conversion and storage under sunlight and heat. We show that macroscopic 3-dimensional structure of graphene-carbon nanotube papers provides advantages over graphene nanomaterials in converting large area power sources, namely solar and thermal energy into considerable current and voltage. We also report a graphene-carbon nanotube paper stack with p-n interfaces that incorporates a solar/thermal energy cell and a p–n junction capacitor, which can be simultaneously used for energy conversion and storage with a charge-storage capacity of 70.5 μC cm −2 at one sun intensity. [ABSTRACT FROM AUTHOR]

Abstract: Inorganic fiber network including YSZ fiber which acts as catalyst support was created by the simple paper-making process, and novel Ni-loaded paper-structured catalysts (PSCs) with excellent catalytic activity for the dry reforming of methane were designed and developed. The PSCs exhibited high fuel conversion comparable to the conventional powdered catalysts with less than one-tenth catalyst weights. The significant advantages of the PSCs are their high mechanical flexibility and material workability. So far, a functionally-graded catalytic reaction field which leads to uniform temperature distribution during biogas reforming resulting in stable operation of planar SOFC was successfully developed by the PSC array based on the kinetic simulation model built in this research. [Copyright &y& Elsevier]

Abstract: A xylanase gene (xynG1-1) from Paenibacillus campinasensis G1-1 was expressed in Bacillus megaterium MS941 and a high level of extracellular xylansae activity (304.26IU/mL) was achieved after induction with 0.5% xylose. The purified recombinant xylanase (XynG1-1R) revealed optimal activity at 60°C and pH 7.0 and retained 79% and 81% activity after incubation without substrate at 60°C, pH 5.0 and pH 8.0 for 3h, respectively. Application of XynG1-1R (15IU/g pulp) to cotton stalk pulp bleaching increased brightness by 3.65% over that of the control without the xylanase and reduced the need for chlorine compounds by 50% without loss of brightness and pulp fiber qualities. When XynG1-1R (80IU/g paper sludge) was used in combination with mixed cellulolytic enzymes, the saccharification efficiency of recycled paper sludge was increased by 10%. These results indicated that XynG1-1R is a promising candidate for various industrial applications such as biobleaching and bioenergy conversion. [Copyright &y& Elsevier]

• A rhombic-shaped paper-based TENG for harvesting mechanical energy is proposed. • Multiple unites are integrated in an harvester to enlarge the electrical output. • The rhombic-shaped frame enables the contact mode TENG to work effectively under tensile conditions. • Two pressurizing braces are designed to enlarge the contact force between the tribo-pair. Triboelectric nanogenerator (TENG) as a promising energy harvesting technology attracts much attention in recent years. Among others, the contact mode TENG is often given priority by virtue of its reliable robustness and high energy conversion efficiency. However, in most cases, the contact-mode TENG is only suitable for collecting energy from pressure-induced incentives because it requires a compression forces to drive. Here, we propose a rhombic-shaped paper-based triboelectric nanogenerator (RP-TENG) that may operate effectively under tensile conditions together with an enhanced contact force between the tribo-pair induced by the design of pressurizing braces. Mechanical tests were carried out to investigate the output performance of the RP-TENG under the activation of various applied forces. An integrated RP-TENG with four tribo-pairs were fabricated for optimizing the output performance. The novel design facilitates the device to achieve higher energy conversion efficiency and also expand its application circumstances. A theoretical model is developed to establish the correlation between the output voltage of the RP-TENG and the geometric characteristics as well as external excitations. The results suggest an effective strategy of using paper-based rhombic-shape design to enhance contact-mode TENGs and may serve as a guideline for structural and circuit design of this novel TENG devices. [ABSTRACT FROM AUTHOR]

Given the low price and abundance of alkali lignin from pulp and paper industry, the conversion of alkali lignin into valuable chemicals has been of great significance to address the world energy crisis. In principle, this process has long relied on the design of a functionalized catalyst to enable high reactivity and selectivity. Herein, we present a systematic study on the hydrogenation liquefaction of alkali lignin using a series of flower-like hierarchical MoS 2 –based catalysts, in which, the effect of various reaction parameters, such as temperature, H 2 pressure, and reaction time, on product yield and distribution was evaluated. Catalysts were characterized by Powder X-ray diffraction, transmission electron microscopy and scanning electron microscopy. N 2 adsorption-desorption isotherms, surface area, pore size distributions and the average pore diameter of catalysts were also measured and calculated. It is worth noting that the incorporation of a secondary metal sulfide into MoS 2 could significantly enhance the catalytic performance. Particularly, by using 5 wt% CoS 2 /MoS 2 as catalyst and having H 2 pressure, reaction temperature, and reaction time set to be 2.5 MPa, 310 °C, and 1 h, respectively, the highest conversion of alkali lignin could reach 91.26%, with a bio-oil yield of 86.24%. This work thus offers an effective approach to improve the conversion and selectivity in catalytic hydrogenation of alkali lignin into bio-oil by using MoS 2 –based catalysts. [ABSTRACT FROM AUTHOR]

Redox flow batteries represent a remarkable alternative for grid-scale energy storage. They commonly employ carbon felts or carbon papers, which suffer from low activity towards the redox reactions involved, leading to poor performance. Here we propose the use of electrospun freestanding carbon materials derived from lignin as alternative sustainable electrodes for all-vanadium flow batteries. The lignin-derived carbon electrospun mats exhibited a higher activity towards the VO 2 +/VO2+ reaction than commercial carbon papers when tested in a three-electrode electrochemical cell (or half-cell), which we attribute to the higher surface area and higher amount of oxygen functional groups at the surface. The electrospun carbon electrodes also showed performance comparable to commercial carbon papers, when tested in a full cell configuration. The modification of the surface chemistry with the addition of phosphorous produced different effect in both samples, which needs further investigation. This work demonstrates for the first time the application of sustainably produced electrospun lignin-derived carbon electrodes in a redox flow cell, with comparable performance to commercial materials and establishes the great potential of biomass-derived carbons in energy devices. Image 1 [ABSTRACT FROM AUTHOR]

Clean energy devices have a great ability to change the world because they strengthen the economy and preserve society. The continuous improvement and progress in nanomaterials and nanotechnology have a great role in human life. The increasing prevalence of PEM fuel cells makes them one of the most viable sustainable energy sources. Nanostructured materials synthesis methodologies have introduced a breakthrough and found to overcome the obstacles for PEMFC commercialization. Amongst them, wet chemical approaches are rapidly expanding and beneficial for the fabrication of nanoparticles since they contribute toward the attainment of a range of essential nanoparticle characteristics like sizes, morphologies, structures, and phases. Wet chemical manufacturing enables fine-tuning of reaction parameters to generate the desired nanomaterials. This review article focuses on the latest improvements in wet chemical methods to better regulate the quality of nanomaterials. This paper examines how wet chemical approaches (hydrothermal synthesis, spray pyrolysis, sol-gel processing, and co-precipitate synthesis, among others) can contribute to the scalable manufacturing of nanoparticles to uphold rising industrial requirements. And how wet chemical methods have a significant influence on power generation systems (Fuel cells) along with their pros and cons. This review carefully analyzes and summarizes synthetic methods and optimized factors in order to prepare nanoparticles and carefully analyzes the reported data. In this paper, the electrochemical analysis, morphological evaluation, compositional analysis, and performance testing of materials produced using wet chemical techniques have been investigated. Recent signs of progress and innovative techniques used to overcome the complexities of synthetic nanoparticle processing. This article is a holistic approach including social, economic, and ecological aspects in the wet chemical process and will certainly help in the fabrication, and application of nanoparticles for PEM Fuel cells. [Display omitted] • Introduction to the status of materials synthesis in energy generating devices. • Overview of wet chemistry Approaches for PEMFC. • Impact of synthesis parameters on properties of materials. • Pros and Cons of wet chemistry techniques for material synthesis. [ABSTRACT FROM AUTHOR]

A bio-inspired nanofibrous Co 3 O 4 /TiO 2 /carbon composite was fabricated using natural cellulose substrate (laboratory filter paper) as both the carbon source and the structural scaffold. Employing a surface sol–gel process to form a thin TiO 2 gel layer coating on each cellulose nanofiber of the filter paper, the resulted composite sheet was successively carbonized in inert atmosphere to give a nanofibrous TiO 2 /carbon composite; afterwards, nano-sized Co 3 O 4 particles (10–30 nm) were uniformly deposited onto the yielded composite fibers via a simple hydrothermal method, resulting in the Co 3 O 4 /TiO 2 /carbon hybrid. The ternary composite possessed a unique hierarchically three-dimensional porous structure which inherited precisely from the initial filter paper. This special structure with the internal conductive carbon fiber and the external nano-sized Co 3 O 4 particles offered the nanocomposite with an excellent electrochemical performance as anodic material for lithium-ion batteries. The optimal sample with a Co 3 O 4 mass content of 50.6% delivered an initial discharge capacity of 1239 mAh g−1 at a current density of 100 mA g−1, which was far exceeded the theoretical capacity of Co 3 O 4. The extra capacity is ascribed to the additional lithium storage sites provided by the large specific surface area of the composite, and the formation of the solid electrolyte interface (SEI) layer in the initial discharge process causing a large consumption of Li+ which results in some irreversible capacity. And after 200 discharge/charge cycles, a high reversible capacity of 764 mAh g−1 was maintained, which is higher than most of the Co 3 O 4 /carbon hybrid materials reported. This work provided a simple and efficient strategy for designing and preparing nanoscale metal-oxide/carbon composite material with considerable potential in energy storage and conversion. Nanofibrous Co 3 O 4 /TiO 2 /carbon composite derived from cellulose substance was fabricated, showing enhanced electrochemical performances as an anodic material for lithium-ion batteries. Image 1 • A cellulose derived nanofibrous Co 3 O 4 /TiO 2 /carbon composite was fabricated. • Nanosized Co 3 O 4 particles were coated uniformly on the nanofiber surfaces. • The composite possessed a unique hierarchically porous net work structure. • It exhibited superior electrochemical performances as anodic material for LIBs. [ABSTRACT FROM AUTHOR]

In the field of research on renewable energy conversion and storage methods, the development of catalysts with excellent properties and outstanding stability for oxygen evolution reaction (OER) acting at various pH values has become a much-anticipated research focus. RuO 2 as a benchmark OER catalyst, its wide application has always been limited by slow reaction kinetics and limited persistence. In this paper, Mn-doped RuO 2 material was developed and the optimum doping ratio was identified for using as an OER electrocatalyst under general purpose pH media. Mn 0.1 Ru 0.9 O 2 exhibited a lower overpotential value of 224 mV in acidic environment with a Tafel slope value of 51.62 mV dec−1. Moreover, in alkaline and neutral environments, overpotentials of 231 mV and 376 mV were required to obtain a current density of 10 mA cm−2, respectively. In addition, through continuous stability testing over 24 h in alkaline, acidic and neutral solutions, it has been further demonstrated that the Mn-doped RuO 2 material exhibits extremely high stability. The advancements in this research offer crucial insight into the rational development of efficient and durable RuO 2 -based catalysts. [Display omitted] • Mn 0.1 Ru 0.9 O 2 is successfully synthesized by a facile sol-gel method. • Mn doping modulates the electronic structure of RuO 2. • The catalyst exhibits enhanced OER activity and stability in pH-Universal media. [ABSTRACT FROM AUTHOR]

With the energy revolution and the proposal of "double carbon" background, hydrogen energy with rich reserves, clean and low carbon and broad application prospects has gradually become a global hot spot. The combination of seawater hydrogen production and offshore wind power is undoubtedly the focus of research in this field. However, this new research field is not yet mature and is still in its infancy, so in order to reduce unnecessary losses, it is crucial to identify the key risks and prevent them. Secondly, the adaptability of a single model is no longer reliable for the risk assessment of this emerging field, especially the conversion from offshore wind to electric energy to hydrogen energy. Based on the above, this paper first considers the ambiguity and uncertainty of information, as well as the risk attitude of decision makers in the evaluation process, and develops a novel evaluation model. The reliability and optimization of the model are verified by sensitivity analysis and comparative analysis, and a case is introduced for practical analysis. The final results show that the key risks of hydrogen production from offshore wind power are seawater electrolysis technology, hydrogen energy storage technology and high-quality wind energy resources. The overall risk is 0.4198, which is medium risk. Decision-making managers can make targeted risk prevention to reduce losses and promote the stable operation of offshore wind power hydrogen production. [Display omitted] • Offshore wind power combined with seawater hydrogen production. • An improved model based on spherical fuzzy theory and cumulative prospect theory. • Taking China 's first large-scale offshore wind power hydrogen production project as a case study. • Key risks: seawater electrolysis technology, hydrogen storage technology and wind energy resources. • The quantitative result of the overall risk assessment was 0.4198. [ABSTRACT FROM AUTHOR]

Vanadium Flow Batteries (VFBs) are a stationary energy storage technology, that can play a pivotal role in the integration of renewable sources into the electrical grid, thanks to unique advantages like power and energy independent sizing, no risk of explosion or fire and extremely long operating life. The first part of this paper presents the main features and the basic performance parameters of VFB, which determine their electric, hydraulic, thermal, and aging feature. The latter part outlines the strengths and weaknesses of the technology, the services that it can provide to the grid, and a short economic analysis. After presenting the fundaments of the technology, prospects and trends of VFBs deployment are outlined. Most of the considerations highlighted in this paper are inspired to studies performed on an industrial-size VFB operated at the Electrochemical Energy Storage and Conversion Lab (EESCoLab) at the University of Padua (Italy). [ABSTRACT FROM AUTHOR]

This paper introduces a smart cyber physical multi-source energy system for electric vehicle applications. This system is realized in order to increase the autonomy of the vehicle as well as a good self-dispatch energy system. In this paper, three energy sources have modeled and integrated in the energy conversion chain of the vehicle. Moreover, the design of cyber energy dispatching system is proposed based on the genetic algorithm NSGA-II. Finally, the simulation and experimental results are demonstrated. [ABSTRACT FROM AUTHOR]

• Stepped displacer plus bypasses is proposed attempting to improve energy conversion efficiency through naturally introduce DC flows by bypasses. • With additional positive DC flows in the 1st stage regenerator and the 2nd stage regenerator, cooling power at 20 K reaches 2.69 W, which is improved by 89 % compared to the model without DC flows. • For the two-stage pulse tube cooler with stepped displacer as the phase shifter, clearance gaps between the displacer piston and cylinder shell induce negative DC1 flow and DC2 flow, which leads to performance deterioration. • A cooling power of 2.04 W at 20 K is obtained with stepped displacer plus bypasses, and the relative Carnot efficiency reaching 13.0 %, which is 56.9 % higher than the values only with stepped displacer. Stirling-type pulse tube cooler (SPTC) is the most prospective thermoacoustic refrigerator due to its long lifetime, high reliability and low vibration, and the phase shifter significantly affects the energy conversion efficiency of SPTC. A novel phase shifter of the stepped displacer plus bypasses (SD-B) is proposed in this paper. Thermoacoustic impedance characteristics of the stepped displacer (SD) and the stepped displacer plus bypasses (SD-B) are analyzed. Based on a two-stage SPTC, the effect of additional combined DC flows in the system is first investigated. Results indicate that the cooling capacity could be improved through introducing additional DC flows in the positive direction from the hot end of regenerator to pulse tube. While for SD, negative DC flows are induced due to the clearance seal gaps between the displacer piston and cylinder shell. Thus, SD-B is explored to improve energy conversion efficiency through naturally introducing DC flows by bypasses. The influence of the opening diameter of two bypasses is investigated, and comparisons between the SD and SD-B are performed. Results indicate that with SD-B, the cooling capacity at 20 K achieves a maximum of 2.04 W with a relative Carnot efficiency of 13.0 %, 56.9 % higher than that of SD. [ABSTRACT FROM AUTHOR]

• Active and robust nanoscale IrO 2 applied Ti anode (IrO 2 /Ti) was constructed. • Polymer electrolyte alcohol electrosynthesis cell (PEAEC) with IrO 2 /Ti was built. • The highest energy efficiency on PEAEC for glycolic acid production was achieved. Performance of a polymer electrolyte alcohol electrosynthesis cell (PEAEC) using a glycolic acid (GC)/oxalic acid (OX) redox couple was enhanced via the multiscale approach, i.e., increase of reaction rate on an anode by employing nanometer-scale (nanoscale) IrO 2 catalysts and increase of selectivity for GC production via optimization of cell structures, i.e., a millimeter-scale approach. We prepared nanoscale IrO 2 anode catalyst, which is mixture of IrO 2 nanoparticles (d = 3.7 ± 1.8 nm) and their agglomerates (d < 200 nm). The linear sweep voltammetry measurement for water oxidation revealed that the nanoscale IrO 2 catalyst deposited on a porous carbon paper reduces overpotential for water oxidation by 196 mV from that obtained with an anode composed of commercial microscale IrO 2 grans. Furthermore, application of the nanoscale IrO 2 catalyst on porous titanium paper not only improved durability but also doubly enhanced water oxidation performance. We examined various PEAEC architectures composed of the nanoscale IrO 2 applied Ti anode. Both nanometer- and millimeter-scale approaches realized the best PEAEC performance for GC production, i.e., 59.4% of energy conversion efficiency with 97.1% of Faradaic efficiency for the GC production at 1.8 V and 98.9% of conversion for 3 M OX , which is an almost saturated aqueous solution at operating temperature of the PEAEC (60 °C). [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction reaction (NO 3 RR) provides a promising method for ammonia (NH 3) producing. It is urgent to develop efficient catalysts with improved NO 3 RR performance. In this paper, Cu 3 P@Co(OH) 2 /CF heterostructure catalyst is constructed by electrodeposition of cobalt hydroxide (Co(OH) 2) nanosheet on the surface of copper phosphide (Cu 3 P) nanorod, and used as a self-supporting cathode for electrocatalytic reduction of nitrate to ammonia. The NH 3 yield reaches 0.19 mmol h−1 cm−2 at a potential of −0.17 V vs. RHE, and the faraday efficiency (FE) is 86.7 %. The study manifests that the built-in electric field generated at the p-n heterojunction interface optimizes the electron migration kinetics, and promotes the adsorption of nitrate and the convention of intermediate product NO 2 − into ammonia. As a consequence, the selectivity of NH3 is improved. The Zn-nitrate battery is assembled with the designed catalyst as the cathode, to reach a peak power density of 5.16 mW cm−2. The prepared catalyst realizes three effective functions: power output, ammonia synthesis, and nitrate pollutants treatment. [Display omitted] • Cu 3 P@Co(OH) 2 /CF heterostructure material was synthesized by low temperature phosphating and electrodeposition methods. • The built-in electric field at the p-n heterojunction promotes the convention of intermediate NO 2 − into ammonia. • Cu 3 P@Co(OH) 2 /CF effectively promotes the *H pathway for NO 3 − reduction to NH 3. • Zn-nitrate battery was built with Cu 3 P@Co(OH) 2 /CF cathode to realize multi-functional applications. [ABSTRACT FROM AUTHOR]

To alleviate the energy crisis and achieve green energy conversion, the heterojunctions that can be applied to the photocatalytic decomposition of water have attracted attention. In this paper, we design a novel two-dimensional GeC/SnSe 2 heterostructure and investigate in detail the structural stability, electronic characteristics, photocatalytic activity and optical behavior as well as the effects due to the applied strain based on the first-principles. Firstly, the most stable γ-stacking mode is determined by combining energy comparison, thermodynamic and dynamic studies. Second, the analysis of electronic properties demonstrates that the GeC/SnSe 2 heterostructure exhibits a type-II energy band arrangement and a direct Z-scheme photocatalytic mechanism. This pivotal aspect enhances the separation of photogenerated carriers at the interface and facilitates the active participation of the most proficient materials in oxidation-reduction processes during photocatalytic hydrolysis reactions. The hydrolysis reaction's Gibbs free energy shift demonstrates the GeC/SnSe 2 heterostructure's superior photocatalytic activity in neutral and alkaline environments and can spontaneously carry out the overall hydrolysis reaction, and this outstanding ability is not affected by the −4% to 4% strain range. In addition, the GeC/SnSe 2 heterostructure has outstanding solar-to-hydrogen efficiency (58.18%) and excellent light absorption capability (up to 4 × 1 0 5 cm − 1 ) within visible light. The implications of these discoveries point towards the direct Z-scheme GeC/SnSe 2 heterostructure holds promise as an excellent candidate for photocatalytic water splitting applications. Free energy descriptions of the GeC/SnSe 2 heterostructure participating in water splitting (a) hydrogen evolution reaction and (b) oxygen evolution reaction under different conditions. Top and side views of the most stable adsorption sites for (c) H on the GeC layer and (d) OH, (e) O and (f) OOH on the SnSe 2 layer of the GeC/SnSe 2 heterostructure. The H and O atoms are represented by pink and red balls, respectively. [Display omitted] • The GeC/SnSe 2 heterostructure is thermodynamic, dynamic and thermal stable. • The GeC/SnSe 2 heterostructure exhibits direct Z-scheme mechanism and strong redox capacity. • Gibbs free energy diagram of water splitting demonstrates its excellent spontaneous reaction capability. • The GeC/SnSe 2 heterostructure has excellent light absorption capability within visible light. [ABSTRACT FROM AUTHOR]

Achieving low cost at high performance is difficult for direct ammonia microfluidic fuel cell (DAMFC) as a portable clean energy conversion device. In this work, a DAMFC with Ni nanoparticles anode and catalyst-free cathode is proposed to realize low cost and high performance of the fuel cell at room temperature. Due to the uniform distribution and spherical geometry of the Ni nano-catalyst, the Ni anode prepared by cyclic voltammetry owns excellent activity of ammonia oxidation. Meanwhile, sodium persulfate having strong oxidizing properties is selected as the oxidant, resulting in catalyst-free carbon paper by cyclic voltammetry treatment directly used as the cathode to greatly reduce the cost of the DAMFC. By optimizing the electrodeposition conditions of Ni electrode and the operating conditions of fuel cell, the DAMFC achieves optimal performance. The maximum power density is 8.43 mW cm−2 and the limiting current density is 78.58 mA cm−2, which is higher than that of most previously reported low-temperature ammonia fuel cells. Moreover, the fuel cell has good stability. Therefore, it proves that a DAMFC with Ni nanoparticles anode and catalyst-free cathode is an effective method to realize low cost and high performance of the ammonia fuel cell at room temperature. [Display omitted] • A low-cost and high-performance ammonia microfluidic fuel cell is proposed. • The spherical nickel nanoparticle catalyst with uniform dispersion is prepared. • Sodium persulfate with strong oxidizing property is selected as oxidant. • The effect of reactant concentration on cell performance is discussed. • The introduction of sodium persulfate removes noble-metal catalyst and improves cell performance. [ABSTRACT FROM AUTHOR]

Modern energy systems are large distributed systems and, as a rule, contain energy storage systems and, in particular, hydrogen batteries and hydrogen production systems. The use of hydrogen for energy transportation has recently been actively studied in a number of scientific projects. To ensure continuous operation of instrumentation and control equipment on long hydrogen pipelines (gas and cryogenic), it is important to ensure constant autonomous power supply to these systems. This can be solved using micromechanical energy microgeneration systems for the uninterrupted operation of various sensors, which are installed in large numbers on almost all elements of the structure and infrastructure. In addition, an important area of scientific research is the revision of the concepts and appearance of traditional devices of modern renewable energy: windmills, solar cells, turbines, etc. Fundamentally new energy devices are on the agenda, capable of recovering mechanical energy of any power and supplying it to the consumer in the form of a given specific energy flow. Collection of chaotically distributed natural energy of the environment (mechanical energy in the form of: vibrations, acoustic vibrations, wave energy, gusts of wind, tornadoes, precipitation, vibrations of the earth's crust, etc.), as well as collection of dissipated energy from artificial sources (iron and automobile highways, airstrips, spaceports, production facilities, etc.) with the help of mechanical microgenerators will allow the recovery and conversion of mechanical energy of various powers, including low power, into a universal energy carrier - hydrogen. Mechanical vibrations of artificial origin are of particular interest due to their widespread use for domestic and industrial purposes in a wide range of vibrations. The energy of mechanical vibrations can be collected and converted into electrical energy using piezoelectric, electromagnetic, triboelectric or electrostatic (capacitive) energy converters. Electrostatic microelectromechanical energy converters are considered the most promising among other energy converters, since their manufacturing processes are based on standard technology for the production of integrated circuits and microelectromechanical systems. Energy conversion by an electrostatic converter is carried out due to an external mechanical force that does work against the force of attraction of the charged electrodes of a variable capacitor. To transfer the received electrical energy to the load of the consuming device, the electrostatic converter is connected to the corresponding electrical circuits (conditioning circuits). Such a system as a whole is a kind of microgenerator or energy collector. Microenergy flow recovery systems integrated into large energy systems will ensure the collection and recovery of significant amounts of energy for remote energy consumers. At the same time, the concept of a distributed mechanical energy recovery system is quite simple: a mechanical energy receiver - a converter into electrical energy - a preliminary electrical storage device - an energy distributor - an electric energy accumulator - an electrolyser - a hydrogen accumulator - a fuel cell. To optimize the operation of the working circuit, including preliminary electrical systems for energy storage and conversion: capacitors and electric energy accumulators, electrolyzers; To ensure their durability and reliability, flexible automatic control of electrical power distribution is necessary. The real work was done to solve that problem. In addition, for extended and large power facilities it is important to ensure widespread sensory control of system parameters. At the same time, if all sensors receive power from an autonomous energy-generating device, then the costs of creating extended communications for instrumentation will be sharply reduced. In addition, the reliability of the control system will significantly increase. The results of studying operation features of a kinetic microgenerator with reduced output voltage are presented. The performance of a multi-stage modified Bennet doubler is compared to a system including a two-stage modified Bennet doubler and a diode-capacitor voltage divider. It is shown that with an increase of the number of stages in the modified Bennet doubler, the conversion of mechanical energy into electrical energy becomes less and less efficient. At the same time, for achieving the maximum energy accumulation rate (power), a two-stage power amplifier based on the Bennet doubler is preferable. It is established that when analyzing the operation of a diode-capacitor voltage divider, it is necessary to take into account the intrinsic (reverse) capacitances of the discharging diodes affecting the divider operation significantly. The divider behavior features while changing the load resistance and the intrinsic capacitances of the discharge diodes are found and analyzed. Analytical expressions linking the main characteristics of the microgenerator as a whole with the parameters of the electronic components used are derived. It is shown that for expanding the range of the "correct" division of the divider, it is necessary to use discharge diodes with minimal intrinsic capacitances, and also that connecting a load to the Bennet doubler as a voltage divider changes the permissible capacitance modulation depth of the variable capacitor. This paper examines the concepts of creating large energy-generating flows based on arrays of micromechanical energy converters placed on optimal energy-efficient receiving surfaces and analyzes the issues of cryogenic production, storage, consumption and transportation of hydrogen. Stationary and mobile cryogenic storage systems for hydrogen are considered. Much attention is paid to the safety of large cryogenic and gas hydrogen systems. [ABSTRACT FROM AUTHOR]

• A novel system is proposed to utilize LNG cold energy in cascade. • Thermodynamic and economic analyses are carried out for the proposed system. • The system is compared to other systems in the same field for performance evaluation. • The round-trip efficiency of the proposed energy storage system is 138.81 %. For cutting down the energy consumption and improving the cold energy conversion efficiency of the traditional liquefied air energy storage system (LAES), a novel energy system integration solution is proposed by combining the LAES with liquefied natural gas (LNG) regasification process. In this paper, the principal energy storage and energy release processes are simulated by Aspen Hysys. The influences of air mass flow rate and LNG regasification pressure on the performance are analyzed. The results indicate that the introducted system can attain 137.82 % round-trip efficiency, which is about 20 % higher than the conventional LAES system. Besides, the energy capacity reaches up to 10.87 MW and the exergy efficiency is 39.58 % during long-distance transportation. It's noteworthy that the power output in the liquefied air energy discharging period far exceeds the power generation from the organic Rankine cycle. The higher LNG transport pressure, the worse LNG-LAES system performance. When the air mass flow rate raises from 40,000 kg/h to 64,000 kg/h, the exergy efficiency is 3.4 % higher than the original, while the round-trip efficiency decreases by 29.79 %. Finally, through economic viability calculations, the dynamic recovery period of the LNG-LAES system is 5.41 years. [ABSTRACT FROM AUTHOR]

The escalating concern over conventional antibiotic resistance has emphasized the urgency in developing innovative antimicrobial agents. In recent times, metal−organic frameworks (MOFs) have garnered significant attention within the realm of antimicrobial research due to their multifaceted antimicrobial attributes, including the sustained release of intrinsic or exogenous antimicrobial components, chemodynamically catalyzed generation of reactive oxygen species (ROS), and formation of photogenerated ROS. This comprehensive review provides a thorough overview of the synthetic approaches employed in the production of MOF-based materials, elucidating their underlying antimicrobial mechanisms in depth. The focal point lies in elucidating the research advancements across various antimicrobial modalities, encompassing intrinsic component release system, extraneous component release system, auto-catalytical system, and energy conversion system. Additionally, the progress of MOF-based antimicrobial materials in addressing wound infections, osteomyelitis, and periodontitis is meticulously elucidated, culminating in a summary of the challenges and potential opportunities inherent within the realm of antimicrobial applications for MOF-based materials. Growing concerns about conventional antibiotic resistance emphasized the need for alternative antimicrobial solutions. Metal-organic frameworks (MOFs) have gained significant attention in antimicrobial research due to their diverse attributes like sustained antimicrobial components release, catalytic generation of reactive oxygen species (ROS), and photogenerated ROS. This review covers MOF synthesis and their antimicrobial mechanisms. It explores advancements in intrinsic and extraneous component release, auto-catalysis, and energy conversion systems. The paper also discusses MOF-based materials' progress in addressing wound infections, osteomyelitis, and periodontitis, along with existing challenges and opportunities. Given the lack of related reviews, our findings hold promise for future MOF applications in antibacterial research, making it relevant to your journal's readership. [Display omitted] [ABSTRACT FROM AUTHOR]

Multigenerational energy conversion plants are one of the most promising solutions for tackling environmental challenges and making efficient use of energy sources. In this regard, a newly designed multigeneration plant integrated with a methane-based Brayton cycle, a steam Rankine cycle, a supercritical CO 2 -based Brayton cycle, a multi-effect desalination process, a PEM unit, a domestic water heater process, and two thermoelectric generators is integrated, proposed and analyzed. The thermodynamic and environmental assessments of the developed paper are conducted and examined with energy and exergy efficiencies as well as CO 2 emission rate. Similarly, a parametric study is executed and reported, by the way, to define the impact of the various significant factors on the developed plant's efficiency. In the end, the CO 2 emission rate is determined and compared according to different energy conversion plants. In light of the analysis results, the net power, hydrogen, and freshwater production capacities of the reference study are calculated to be 1336 kW, 0.002004 kgs−1, and 0.954 kgs−1, respectively. Additionally, it is found that the developed study's energetic and exergetic performances are 55.76% and 52.17%. According to emission analysis results, the multigeneration system emits 272.2 k g / M W h less CO 2 emissions than the single energy conversion system. • A newly designed multigeneration plant is suggested. • Combination of a superciritical CO 2 based Brayton cycle is proposed. • Thermodynamic and environmental analysis of the multigeneration plant is conducted. • Freshwater, hydrogen, power and heating purposes are fulfilled. • The overall energy and exergy efficiencies are 55.76% and 52.17%, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a novel energy management strategy (EMS) to control a wind-hydrogen microgrid which includes a wind turbine paired with a hydrogen-based energy storage system (HESS), i.e., hydrogen production, storage and re-electrification facilities, and a local load. This complies with the mini-grid use case as per the IEA-HIA Task 24 Final Report, where three different use cases and configurations of wind farms paired with HESS are proposed in order to promote the integration of wind energy into the grid. Hydrogen production surpluses by wind generation are stored and used to provide a demand-side management solution for energy supply to the local and contractual loads, both in the grid-islanded and connected modes, with corresponding different control objectives. The EMS is based on a hierarchical model predictive control (MPC) in which long-term and short-term operations are addressed. The long-term operations are managed by a high-level MPC, in which power production by wind generation and load demand forecasts are considered in combination with day-ahead market participation. Accordingly, the hydrogen production and re-electrification are scheduled so as to jointly track the load demand, maximize the revenue through electricity market participation and minimize the HESS operating costs. Instead, the management of the short-term operations is entrusted to a low-level MPC, which compensates for any deviations of the actual conditions from the forecasts and refines the power production so as to address the real-time market participation and the short time-scale equipment dynamics and constraints. Both levels also take into account operation requirements and devices' operating ranges through appropriate constraints. The mathematical modeling relies on the mixed-logic dynamic (MLD) framework so that the various logic states and corresponding continuous dynamics of the HESS are considered. This results in a mixed-integer linear program which is solved numerically. The effectiveness of the controller is analyzed by simulations which are carried out using wind forecasts and spot prices of a wind farm in center-south of Italy. • Design of control algorithms for islanded and grid-connected microgrids. • Development of hierarchical MPCs to target long-term and short-term operations. • Tracking the load demand and maximizing the revenue via electricity markets. • Minimization of the HESS operational costs. [ABSTRACT FROM AUTHOR]

At present, energy shortage and environmental pollution are becoming more and more serious. If environmental governance and energy supply can be combined, it will be more consistent with the long-term concept of sustainable development. Urea electrooxidation may achieve the degradation of pollutants and the conversion of energy supply, urea oxidation occurs at the anode and hydrogen evolution occurs at the cathode. However, the electrochemical oxidation process of urea requires the transfer of six electrons, and the reaction rate is slow. The electrocatalyst is a key factor in improving the reaction kinetics. In this context, catalysts used in urea electrocatalytic oxidation in recent years are reviewed in this paper. The application of the electrocatalyst in electrolytic hydrogen production, urea wastewater treatment, urea fuel cells and urea sensors are described in detail. In addition, the future research directions, research emphases and areas needing improvement of these catalysts are discussed. [Display omitted] • Urea electrooxidation has double benefits of environmental protection and energy supply. • Electrocatalysts for urea electrooxidation in alkaline electrolytes are reviewed. • The applications of electrocatalyst in the electrooxidation of urea are demonstrated. [ABSTRACT FROM AUTHOR]

The utilization of heterostructures as photocatalysts for water decomposition is a promising method to tackle contemporary environmental challenges. This research paper presents the design of a direct Z-scheme heterostructure utilizing a monolayer of GeC and a monolayer of arsenene, based on first-principle calculations. The photocatalytic efficiency of this GeC/arsenene van der Waals (vdW) heterostructure in a direct Z scheme has been investigated. The presence of a built-in electric field from the GeC monolayer to the arsenene monolayer has been established through an analysis of band alignment, work function, charge density, and Bader charge. The GeC/arsenene heterostructure exhibits excellent and robust optical absorption efficiency for the sunlight, alongside achieving the maximum solar-to-hydrogen (STH) energy conversion efficiency, amounting to 7.28%, under a biaxial strain of +4%. Furthermore, the Gibbs free energy changes in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) of the GeC/arsenene heterostructure have been calculated. The outcomes indicate that the GeC/arsenene heterostructure is a feasible semiconductor for photocatalytic water splitting. Band edge positions and Z-scheme photocatalytic mechanism of the GeC/arsenene heterojunction. [Display omitted] • GeC/arsenene heterostructure has a built-in electric field from GeC to arsenene layer. • GeC/arsenene heterostructure exhibits a high optical absorption under biaxial tensile strain. • The highest solar-to-hydrogen efficiency of 7.28% is obtained under +4% strain. • High catalytic activity for the hydrogen evolution reaction is confirmed by free energy calculations. [ABSTRACT FROM AUTHOR]

Linear transverse flux permanent magnet machines (LTFPMs) are categorized as high force density topologies, which are suitable candidates for direct drive and low-speed applications. This paper introduces a novel LTFPM topology, which also proposes advantages of the flux-switching machines. This proposed linear transverse flux switching PM machine (LTFSPM) has two long passive translators located at the armature's top and bottom sides. The topology offers a high value of force density, and also, it is a cost-effective topology due to its double-sided passive translator. Furthermore, the PMs are fully utilized in the magnetic circuit, the end winding length is negligible, and the iron cores can be laminated easily. In this paper, the operation principle of the topology is explained and its magnetic circuit is discussed. To reduce the computational time of optimization procedure, a double-layer method is adopted, which provides high robustness, low computational time, and high precision. Results of the finite element method indicate that the proposed machine can be considered a potential candidate for linear motion applications especially direct drive wave energy conversion systems, which require high force density values. [ABSTRACT FROM AUTHOR]

The miniaturization, portability, and reduction in power consumption of wearable devices have greatly facilitated significant advancements in the field of wearable human energy harvesting systems. Human metabolism results in waste heat production and dissipation to the surroundings via skin radiation, convection, and evaporation. Wearable flexible thermo-electric and moist-electric devices uses skin waste heat harvesting to convert thermal energy into electricity without user involvement. The principle and structure of the device is simple and pollution free with great application potential in generating power supply. Skin waste heat can be dissipated in the forms of both sensible and latent heat. Wearable thermo-electric generators (WTEGs) collects sensible heat, and wearable moist-electric generators (WMEGs) collects latent heat. This paper reviews the mechanism behind the generator of WTEG and WMEG, as well as state-of-the-art research progress made in material properties and structural design of thermoelectric devices. The performance optimization and design of wearable, flexible thermoelectric devices for skin waste heat harvesting at the material and device levels are studied, followed by a breakdown on the fibers and fabrics used in the foundation for future development of WTEG and WMEG's. The research findings provides valuable insight on the future development of WTEG and WMEG's, providing integration into wearable applications for health and physiological monitoring and disease diagnosis. This paper reviews the mechanism behind the generator of WTEG and WMEG, as well as state-of-the-art research progress made in material properties and structural design of thermoelectric devices. The performance optimization and design of wearable, flexible thermoelectric devices for skin waste heat harvesting at the material and device levels are studied, followed by a breakdown on the fibers and fabrics used in the foundation for future development of WTEG and WMEG's. The research findings provides valuable insight on the future development of WTEG and WMEG's, providing integration into wearable applications for health and physiological monitoring and disease diagnosis. [Display omitted] • Explored the theory of thermoelectric energy conversion from skin waste heat. • Overviewed advancements in material properties and structural design of thermoelectric devices. • Studied on improved designs for wearable thermoelectric devices using fiber and fabric materials. • Future directions for wearable flexible thermoelectric devices. [ABSTRACT FROM AUTHOR]

Large ships are more utilized than ever before to facilitate transporting heavy goods and oils overseas. However, they rely on fossil fuels and cause severe environmental impacts. Utilizing alternative fuels and implementing new engine designs are considered promising methods to reduce greenhouse gas emissions and improve engine performance. This paper compares three developed, hybridized marine engines operated using five fuel blends of hydrogen, methanol, dimethyl ether, ethanol, and methane. In addition, the paper presents a multi-objective particle swarm optimization to increase the engine power and its exergetic efficiency and reduce the cost and environmental impact. A marine engine (SRC-GT-SOFC) containing a steam Rankine cycle, a gas turbine, and a solid oxide fuel cell is considered to weigh less and perform better. It is found that the optimized SRC-GT-SOFC engine power is increased by about 10 %, corresponding to 16269 kW with an increased exergetic efficiency of 70.6 %, respectively. Its specific fuel and product exergetic costs are found to be 12 $/GJ and 15.67 $/GJ, and its specific fuel and product environmental impacts are 7.4 Pt/GJ and 9.3 Pt/GJ, respectively. This results in a significant reduction in the relative cost difference and the relative environmental impact difference of the optimized SRC-GT-SOFC of 30 % and 25.4 %, respectively. • Three hybridized marine engines are compared and optimized to raise performance. • Optimized SRC-GT-SOFC engine has 16.3 MW power and 70.6 % exergetic efficiency. • Specific exergetic cost reduced to 12 $/GJ for fuel and 16 $/GJ for product. • Specific exergetic environmental impact for fuel and product becomes 7.4 and 9.3 Pt/GJ. • New operation conditions of SRC-GT-SOFC have low price and environmental impact. [ABSTRACT FROM AUTHOR]

The Near-Space Plasma Electromagnetic Science Experimental Research Apparatus is designed for ground-based simulation of plasma sheath and is capable of providing pure, high-enthalpy, and high-density plasma jets. The high enthalpy implies a high plasma state, which can achieve high Mach equivalent simulation in flight conditions. This paper takes this device as the research object and establishes a multi-physics coupling magnetohydrodynamics model to simulate the heat transfer process under high-power conditions. Through numerical simulation, the distribution rules of plasma temperature and enthalpy value under different power states considering the radiation source are obtained. By combining numerical simulation with experimental verification, the simulated enthalpy and energy conversion efficiency results are compared with experimental data, showing good consistency. The study finds that the enthalpy at the center of the jet outlet is higher, increasing from 5.4 MJ/kg to 9.5 MJ/kg when the high-frequency power increases from 150 kW to 426 kW, with an increase of 4.0 MJ/kg. The overall distribution of plasma jet enthalpy exhibits a central peak, gradually decreasing radially from the center to both sides. Meanwhile, during the axial jet injection process, there is a transition in the radial distribution of temperature and enthalpy, shifting from a saddle-shaped distribution at the coil position to an arch-shaped distribution at the nozzle outlet. In this power range, the energy conversion efficiency of the high-frequency power source ranges from 53% to 30%, with both calculated and measured efficiencies decreasing with increasing power. Additionally, the paper discusses the impact of radiation source terms on the distribution of enthalpy in high-power inductive-coupled plasma. In conclusion, the model proposed in this paper can be used to estimate the outlet enthalpy distribution and energy conversion efficiency of the Near-Space Plasma Electromagnetic Science Experimental Research Apparatus, providing data support for the design, control, and application of the device. • Develops model for simulating plasma heat transfer in high-power settings. • Enthalpy & efficiency simulation aligns well with experiments. • Model predicts device's outlet enthalpy distribution, aiding control and application. [ABSTRACT FROM AUTHOR]

CP@NC-CoFe 2 O 4 /C as catalysts for OER: we covered a polyaniline nanowire array on carbon paper by a electrochemical polymerization method, directly grown MOF-74-Co/Fe on its surface and pyrolyzed to form the CoFe 2 O 4 /C supported on nitrogen-doped carbon nanoarray meterial, which is prepared a highly active and stable OER catalyst. High specific surface area, high utilization of the catalyst, enhanced electron transport characteristics and retention characteristics of the original carbon paper characteristics ensure excellent OER activity. Our results show great promise for developing OER catalysts as precious metal substitutes for PANI and MOFs complexes through a low-cost, scalable method. [Display omitted] • Polyaniline nanowire array was covered on carbon paper, directly grown MOF-74-Co/Fe on its surface. • The presence of PANI nanowire arrays also retains the original properties of carbon paper. • The unique 3D nano-array structure enhance the OER catalytic efficiency. • DFT reveals the main surface adsorbent is OH*, and surface Co atoms are the main active sites. Here, we covered a polyaniline nanowire array (denoted as PANI) on carbon paper (denoted as CP) by a electrochemical polymerization method, directly grown MOF-74-Co/Fe on its surface and pyrolyzed to form the CoFe 2 O 4 /C supported on nitrogen-doped carbon nanoarray materials (denoted as NC-CoFe 2 O 4 /C@CP), which is prepared a highly active and stable OER catalyst. PANI can not only be used as a "binder", grow MOF on its surface and cover the carbon paper, but also improve the conductivity and stability of the material by forming nitrogen-doped carbon after pyrolysis. And its unique 3D nano-array structure not only greatly increases the surface area, but also provides more attachment sites for CoFe 2 O 4 , thereby accelerating electron transport and improving OER performance. High specific surface area, high utilization of the catalyst, enhanced electron transport characteristics and retention characteristics of the original carbon paper characteristics ensure excellent OER activity. The final sample exhibits outstanding activity for OER in alkaline solution, accompanied by a low onset potential about 1.52 V (vs reversible hydrogen electrode), and the small Tafel slope of 70 mV dec−1. In particular, after 21600s, the current drop is negligible, which is means that the NC-CoFe 2 O 4 /C@CP catalyst has the high stability. Density Functional Theory (DFT) calculation reveals the main surface adsorbent of CoFe 2 O 4 is OH*, and the surface Co atoms are the main active sites. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have driven great interest due to a large specific surface area to volume ratio and adjustable surface behaviors, which show huge potentials for enhancing the activity of energy conversion and property optimization. In order to regulate the physicochemical properties of photocatalyst for water splitting reaction, defect engineering on 2D materials have drawn great attention. Meanwhile, a widely used strategy to improve the H 2 evolution rate kinetics has been achieved. In this paper, we prepared AgBr/g-C 3 N 4 catalyst by chemical precipitation. The obtained photocatalyst shows a unique charge transfer pathway. In addition, a deep understanding of the proton shuttle during H 2 evolution reactions can offer profound opinion into heterostructure construction and property optimization. It is found that the enhanced performance is correlated to the superiority of the S-scheme heterojunction and defect engineering on graphitic carbon nitride 2D materials. This work offers a novel method for improving efficiency in terms of energy conversion and property optimization. [Display omitted] • Surface nitrogen vacancy is instrumental in the chemisorption and activation of H 2 O. • S-scheme band of AgBr/g-C 3 N 4 is conjectured by the experiments and DFT calculations. • The prolonged photocarrier lifetime has increased H 2 production. • The results of XPS are consistent with the mechanism of S-scheme heterojunction. [ABSTRACT FROM AUTHOR]