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[Display omitted] • CoFePBA with hierarchical hollow structure was prepared by anion exchange method. • The nanocomposite with hollow structure was prepared by heat-treatment of CoFePBA. • The synergistic effect among different components significantly enhanced OER activity. The microstructure of materials importantly affects their performance. As electrocatalyst materials, the performance of hollow-structure materials is usually better than that of solid materials because of the larger specific surface area, lower density, and more exposed active sites of hollow structure. Bimetallic catalysts usually exhibit better catalytic activity than monometallic catalysts because of the synergistic effects between different metal elements. Prussian blue and its analogues (PB/PBAs) are ideal precursors for preparing hollow-structure bimetallic catalysts due to their structure and composition characteristics. In this study, ZIF-67 hollow sphere (HS) was used as the template to prepare hierarchical hollow CoFePBA (H-SCP) through anion-exchange method. The oxygen evolution reaction (OER) catalytic performance of H-SCP was further improved by low-temperature heat treatment in N 2 atmosphere. The H-SCP-350 sample, which was obtained at a heat-treatment temperature of 350 ℃, was a bimetallic nanocomposite. Part of H-SCP was converted into metallic cobalt and cobalt-iron alloy during heat treatment. The synergistic effect among the different components effectively improved the electrocatalytic activity of the material. Therefore, H-SCP-350 showed the best OER catalytic performance among all samples. The overpotential was only 291mV at a current density of 10 mA cm−2 when tested in 1 M KOH electrolyte. [ABSTRACT FROM AUTHOR]

Activated carbons are one of the most important classes of high‐surface‐area porous materials. Owing to their unique structure, low price, and large‐scale production technology, these porous carbons have been traditionally used as sorbents for eliminating contamination. In the past decade, many innovations have been seen in the synthesis, structure, applications, and theoretical and experimental methods. Herein, a comprehensive review of the up‐to‐date progress of activated carbons is presented from the viewpoint of synthetic chemistry and materials science. First, the critical textural properties are discussed, with special emphasis on the porous texture, heteroatom doping, surface functional groups, and partial graphitization. Next, the advanced synthetic strategies of activated carbons are summarized. Special attention is given to the reaction mechanism between activating agents and carbon sources, as well as the design of controlled forms and morphology. Then, their applicability in various emerging fields is covered, including supercapacitors, capacitive deionization, batteries, electrocatalysis, and carbon capture. In particular, this review highlights the potential synthesis–structure–property correlations of these porous materials. Finally, we present the future challenges and outlook for their success in energy and environmental science. [ABSTRACT FROM AUTHOR]

This research examines the effect of environmental policy stringency on green innovation in renewable energy technology and whether the green innovation response differs with varying degrees of environmental policy. Based on panel data of 33 countries over the period 1990–2015, we show that a stringent environmental policy does encourage green innovation in renewable energy technology, and this impact is more pronounced in OECD countries and high-income countries. More specifically, a stringent non-market-based environmental policy induces more patents in renewable energy generation. The findings also show that a stringent environmental policy yields green innovation for geothermal energy, hydro energy, and marine energy, but not for wind energy and solar energy. Heterogeneity analysis suggests that innovation capacity and environmental pressure enhance the impact of environmental policy stringency on green innovation in the renewable energy field. Finally, the paper presents that clean energy investment plays the role of a mechanism through which environmental policy stringency spurs green innovation in the renewable energy field, offering insights into the influence of environmental policy stringency on green innovation. [ABSTRACT FROM AUTHOR]

Using panel data of 102 countries from 1990 to 2018, this research investigates the varying effect of renewable energy policies on renewable energy green innovation along with the distribution of green innovation. The panel quantile model with additive fixed effect is adopted in this paper, and the research conclusions are as follows. (1) Green innovation positively correlates with national renewable energy policy. (2) Renewable policy is more effective in countries with stronger green innovation capacity. (3) In five different areas of renewable energy, renewable policy is unable to promote green innovation in the lowest innovative countries. (4) Renewable policy exerts the smallest influence on green innovation of geothermal energy compared to other renewable energies. In sum, this paper provides an empirical reference for governments to launch renewable energy policies. [ABSTRACT FROM AUTHOR]

• This paper investigates the effect of globalization on innovation by Chinese firms. • Using a combined dataset of 596,809 Chinese manufacturing firms. • We find that overall provincial globalization is associated with better innovation performance for Chinese firms. • China government should continue to attract foreign investors to enhance innovation. This paper investigates the effect of globalization on innovation by using a combined dataset of 596809 Chinese manufacturing firms with 1,993,154 observations and provincial globalization indices from 1998 to 2009. The empirical findings suggest that overall provincial globalization is associated with better innovation performance for Chinese firms. More specifically, economic, social, and political globalization, present positive impacts on technological innovation. Interestingly, through subsample analysis the findings indicate that globalization expresses a distinct relationship with firms' innovation performance. In particular, economic globalization correlates to greater technological innovation in private-owned enterprise, a lower one in stated-owned enterprises, and an insignificant one in foreign-owned enterprises. Moreover, a subsample analysis for different industries exhibits similar results as in the full sample except for the resources-intensive industry in which economic globalization is associated with lower innovation. Our findings indicate that China should continue to enhance connections in the economic, social, and political dimensions with other countries. [ABSTRACT FROM AUTHOR]

Abstract: Lithium‐ion batteries are widely used as reliable electrochemical energy storage devices due to their high energy density and excellent cycling performance. The search for anode materials with excellent electrochemical performances remains critical to the further development of lithium‐ion batteries. Tungsten‐based materials are receiving considerable attention as promising anode materials for lithium‐ion batteries owing to their high intrinsic density and rich framework diversity. This review describes the advances of exploratory research on tungsten‐based materials (tungsten oxide, tungsten sulfide, tungsten diselenide, and their composites) in lithium‐ion batteries, including synthesis methods, microstructures, and electrochemical performance. Some personal prospects for the further development of this field are also proposed. [ABSTRACT FROM AUTHOR]

Abstract: Lithium‐ion batteries (LIBs) have been widely used in the field of portable electric devices because of their high energy density and long cycling life. To further improve the performance of LIBs, it is of great importance to develop new electrode materials. Various transition metal oxides (TMOs) have been extensively investigated as electrode materials for LIBs. According to the reaction mechanism, there are mainly two kinds of TMOs, one is based on conversion reaction and the other is based on intercalation/deintercalation reaction. Recently, hierarchically nanostructured TMOs have become a hot research area in the field of LIBs. Hierarchical architecture can provide numerous accessible electroactive sites for redox reactions, shorten the diffusion distance of Li‐ion during the reaction, and accommodate volume expansion during cycling. With rapid research progress in this field, a timely account of this advanced technology is highly necessary. Here, the research progress on the synthesis methods, morphological characteristics, and electrochemical performances of hierarchically nanostructured TMOs for LIBs is summarized and discussed. Some relevant prospects are also proposed. [ABSTRACT FROM AUTHOR]

Ordered porous CoO materials with pore sizes of 5 nm (CoO-5), 20 nm (CoO-20), and 70 nm (CoO-70) have been synthesized via a hard-template method and were studied as catalysts to bring insight into non-enzymatic electrochemical sensing of glucose. A glassy carbon electrode modified with CoO-70 responds more quickly and sensitively to glucose than those modified with CoO-5 or CoO-20. The sensor based on the use of CoO-70 and operated at a working voltage of 0.6 V (vs. Ag/AgCl) in 0.1 M NaOH solution shows a lower detection limit of 0.025 μM, good repeatability and high selectivity over ascorbic acid, uric acid, dopamine, and KCl. These results suggest that ordered porous CoO is a promising material for quantitative electrochemical determination of glucose, and that the pore size has a strong effect on performance. [ABSTRACT FROM AUTHOR]

Previous research on iron oxides/hydroxides has focused on the crystalline rather than the amorphous phase, despite that the latter could have superior electrochemical activity due to the disordered structure. In this work, a simple and scalable synthesis route is developed to prepare amorphous FeOOH quantum dots (QDs) and FeOOH QDs/graphene hybrid nanosheets. The hybrid nanosheets possess a unique heterostructure, comprising a continuous mesoporous FeOOH nanofilm tightly anchored on the graphene surface. The amorphous FeOOH/graphene hybrid nanosheets exhibit superior pseudocapacitive performance, which largely outperforms the crystalline iron oxides/hydroxides-based materials. In the voltage range between −0.8 and 0 V versus Ag/AgCl, the amorphous FeOOH/graphene composite electrode exhibits a large specific capacitance of about 365 F g−1, outstanding cycle performance (89.7% capacitance retention after 20 000 cycles), and excellent rate capability (189 F g−1 at a current density of 128 A g−1). When the lower cutoff voltage is extended to −1.0 and −1.25 V, the specific capacitance of the amorphous FeOOH/graphene composite electrode can be increased to 403 and 1243 F g−1, respectively, which, however, compromises the rate capability and cycle performance. This work brings new opportunities to design high-performance electrode materials for supercapacitors, especially for amorphous oxides/hydroxides-based materials. [ABSTRACT FROM AUTHOR]

A novel core–shell structured Co 11 (HPO 3 ) 8 (OH) 6 –Co 3 O 4 hybrid material was synthesized in a hydrothermal condition from the microporous Co 11 (HPO 3 ) 8 (OH) 6 microrod precursor. Due to the unique nano/microstructures, the assembled asymmetric all-solid-state supercapacitor (Co 11 (HPO 3 ) 8 (OH) 6 –Co 3 O 4 and graphene) showed a high gravimetric specific capacitance of 1.84 F cm −3 at 0.5 mA cm −2 and an excellent cycling stability with only 1.3% ca decay after 3000 cycling. The device delivered a maximum power density of 105 mW cm −3 at a current density of 1.5 mA cm −2 and possessed a maximum volumetric energy density of 0.48 mW h cm −3 at a current density of 0.5 mA cm −2 . The device also exhibited excellent flexibility. [ABSTRACT FROM AUTHOR]

1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures assembled by ultrathin nanoflakes are synthesized for the first time by a hydrothermal method. We present a self-reacting template method to synthesize 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures using Ni(SO 4 ) 0.3 (OH) 1.4 nanobelts. A high-performance flexible asymmetric solid-state supercapacitor can be successfully fabricated based on the 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures and graphene nanosheets. Interestingly, the as-assembled 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures//Graphene nanosheets asymmetric solid-state supercapacitor can achieve a maximum energy density of 0.496 mWh cm −3 , which is higher than most of reported solid state supercapacitors. Additionally, the device shows high cycle stability for 10,000 cycles. These features make the 1D Co 2.18 Ni 0.82 Si 2 O 5 (OH) 4 architectures as one of the most promising candidates for high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Amorphous core–shell CoO@C and Mn 3 O 4 @C composites have been synthesized by documenting a simple glucose–ethanol-assisted approach and characterized by SEM, TEM, X-ray diffraction, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Electrochemical measurements are performed to examine the CoO@C composites, and the result shows that CoO@C structure has much higher capacitance, higher energy and power density and better cycling performance than that of C/CoO hybrids. This improvement can be attributed to the nature of core–shell structure, which promotes fast Faradaic charging and discharging reaction and also minimizes both the ionic and electronic transportation distances and therefore improves the resulting electrode kinetic performance. [ABSTRACT FROM AUTHOR]

Zinc hydroxide fluoride (Zn(OH)F) with multiform morphologies such as flower-like particles, pumpkin-like aggregates, and hollow orange-like aggregates are prepared by a microwave-assisted ionic liquid method. During synthesis, microwave irradiation accelerates the reaction rate and shortens the reaction time. 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF 4 ]) or 1-2-hydroxylethyl-3-methylimidazolium tetrafluoroborate ([C 2 OHmim][BF 4 ]) is used as both reactant and template. Experimental results indicate that the morphology evolution of Zn(OH)F is mainly controlled by the concentration of zinc acetate solution. A possible mechanism underlying the formation of nanostructured Zn(OH)F with diverse morphologies is proposed. Furthermore, nanoporous ZnO is obtained by the thermal decomposition of as-prepared Zn(OH)F in air, and the morphology is well retained. [ABSTRACT FROM AUTHOR]

Monodisperse mesoporous anatase microspheres were prepared by a combination of sol-gel and liquid-crystal template methods. With the change in annealing temperature, the pore structure parameters of samples were regulated. The influence of pore structure parameters on lithium-ion battery performance was systematically investigated. Results of electrochemical test and analysis demonstrated that the pore structure parameters significantly influenced the specific capacity, charging and discharging curves, rate capability, and cycle performance of the batteries. The first irreversible capacity increased with increased specific surface area. Materials with larger specific surface area showed better rate capability. When the average pore size was too small, the transport of Li in the electrolyte was impeded, which affected the rate capability of the materials. Based on the charging and discharging curves, the capacity of the plateau section corresponding to lithium insertion/extraction ions in the interstitial octahedral sites of anatase became smaller with increased specific surface area. By contrast, the capacity of the oblique line section corresponding to the Li insertion/extraction into/from the surface layer of anatase became larger. The pore volume influenced the cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a novel macro–microporous architecture is successfully constructed in a honeycomb-like structure by directly using rape seed shell via impregation-activation route. This approach permits the high specific surface area (SSA) and a unique hierarchical porous structure which consists of interconnected macroporous skeleton and a significant microporosity. The unique honeycomb-like network combined with high specific surface area is favorable for charging the electric double-layer. The resulting carbon is highly suitable as electrodes of electric double layer capacitors, with remarkable values of capacitance of up to 225Fg−1 at a current density of 1Ag−1 in 2M KOH electrolyte. Therefore, the as-prepared carbon can be a potential candidate for supercapacitors. [Copyright &y& Elsevier]

Abstract: In this work, we report the simple solid-state formation of mesoporous In2O3 nanorods with a quasi-single-crystalline framework. The synthesis is based on controlled thermal oxidative decomposition and re-crystallization of precursor In(OH)3 nanorods obtained from a hydrothermal method without using any surfactants or organic templates. Importantly, the rod-like morphology can be completely preserved after thermal treatment. Due to the intrinsic crystal contraction, a highly mesoporous structure with high specific surface area (up to 103.1m2/g) has been created. The textual properties can be tailored by varying the annealing temperature. The gas sensing test results show that mesoporous In2O3 nanorods possess satisfactory response to dilute ethanol vapor. [Copyright &y& Elsevier]

Abstract: Mg(OH)2 nanoplate with single-crystal structure was synthesized by a solvothermal method without using any surfactants or organic templates. MgO was obtained by annealing Mg(OH)2 at low temperature. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption analysis. The results indicate that MgO sample inherits the nanoplate morphology and single-crystal structure of Mg(OH)2. Moreover, MgO nanoplate has disordered mesoporous structure, large BET surface area, and high pore volume. The BET surface area and pore volume can reach up to 373.2m2/g and 0.71cm3/g. The dehydration of Mg(OH)2 during heat treatment results in the formation of mesopores. The effect of the solvothermal reaction temperature, the solvothermal reaction solvent, and the annealing temperature on the BET surface areas of MgO products was studied. [Copyright &y& Elsevier]

NiO nanoparticles have been prepared by thermal decomposition of the nickel acetate/starch precursor in air. N2 adsorption-desorption analysis show that the resultant NiO samples possess nanoporous structures and large BET surface areas. The Brunauer-Emmet-Teller (BET) surface area of NiO increases from 17 to 38 m2·g−1 because of the use of the starch template. The surface area decreases and the average pore diameter increases for the NiO products with increasing heat treatment temperature. The formation mechanism of the NiO nanoparticles was proposed. Furthermore, the electrochemical measurements indicate that the NiO nanoparticles have favorable faradaic pseudocapacitive behavior. The method has also been demonstrated for nickel nitrate. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic CoFe2O4-functionalized graphene sheets (CoFe2O4–FGS) nanocomposites have been synthesized by hydrothermal treatment of inorganic salts and thermal exfoliated graphene sheets. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show that cobalt ferrite nanoparticles with sizes of 10–40nm are well dispersed on graphene sheets. OH− was recognized as a tie to integrate the inorganic salts with the graphene sheets, which made reaction started and developed on the surface of graphene sheets and formed cobalt ferrite nanoparticles on graphene sheets. The adsorption kinetics investigation revealed that the adsorption of methyl orange from aqueous solution over the as-prepared CoFe2O4–FGS nanocomposites followed pseudo-second-order kinetic model and the adsorption capacity was examined as high as 71.54mgg−1. The combination of the superior adsorption of FGS and the magnetic properties of CoFe2O4 nanoparticles can be used as a powerful separation tool to deal with water pollution. [Copyright &y& Elsevier]

Abstract: Two kinds of functionalized graphene sheets were produced by thermal exfoliation of graphite oxide. The first kind of functionalized graphene sheets was obtained by thermal exfoliation of graphite oxide at low temperature in air. The second kind was prepared by carbonization of the first kind of functionalized graphene sheets at higher temperature in N2. Scanning electron microscopy images show that both two kinds of samples possess nanoporous structures. The results of N2 adsorption–desorption analysis indicate that both of two kinds of samples have high BET surface areas. Moreover, the second kind of functionalized graphene sheets has a relatively higher BET surface area. The results of electrochemical tests is as follows: the specific capacitance values of the first kind of functionalized graphene sheets in aqueous KOH electrolyte are about 230Fg−1; the specific capacitance values of the second kind of functionalized graphene sheets with higher BET surface areas are only about 100Fg−1; however, compared with the first kind of functionalized graphene sheets, the second kind has a higher capacitance retention at large current density because of its good conductive behaviors; furthermore, in non-aqueous EC/DEC electrolyte, the specific capacitance values of the first kind sample and the second kind sample are about 73Fg−1 and 36Fg−1, respectively. [Copyright &y& Elsevier]

Abstract: The microstructures of mesoporous carbon nanofibers were characterized by scanning electron microscopy, transmission electron microscopy, nano-Raman, nitrogen adsorption–desorption and optical transmission. They possessed a high specific surface area 840m2 g−1 and a 1.07eV band gap. All mesoporous carbon nanofiber network can act as the channel material in p-type field-effect transistor devices with field-effect mobilities over 10cm2/Vs. Furthermore, mesoporous carbon nanofiber network exhibits better sensitivity and faster response to NO2 gas than that of carbon nanotubes, which makes it a promising candidate as poisonous gas sensing nanodevices. [Copyright &y& Elsevier]

Hollow cobalt oxide is phosphated under an inert atmosphere to form a composite with interconnected porous structures. As an electrocatalyst for oxygen evolution reaction, the catalytic activity of this material is significantly better than Co 3 O 4. [Display omitted] • Amorphous porous CoP x -CoO y complex was constructed by low temperature phosphating. • The same structure was obtained when the method is applied to other oxides. • The structure can significantly increase the number of active sites required for OER. • The catalytic activity of the material for oxygen release reaction was better than that of Co 3 O 4. Interconnected porous structures and amorphous materials are widely used in the field of electrocatalysis owing to their rich catalytic active sites. Amorphous CoP x -CoO y composites with interconnected porous structures were constructed through low-temperature phosphating of cobalt oxides. Moreover, low-temperature phosphating of cobalt oxide and other metal oxides with different morphologies also produced the same porous structures, further proving the generality of this method. Interestingly, the prepared CoP x -CoO y catalyst has excellent electrocatalytic activity for oxygen evolution reactions in alkaline media. At a current density of 10 mA cm−2, an overpotential of 322 mV and a Tafel slope of 102 mV dec-1 are generated. In a 1 M KOH electrolyte, its electrochemical activity is significantly better than that of unphosphorylated Co 3 O 4. Under catalytic conditions, the excellent performance arises from the formation of the incorporation of phosphorus, amorphous phase and porous structures. The unique structure can provide a large number of active sites, significantly shortening the electron transfer pathway. This is the foundation of our research on the development of electrocatalysts with rich active sites. The synthesis of amorphous interconnected porous structures by introducing phosphorus will allow the application of high-efficiency catalysts in electrocatalysis and other important chemical reactions. [ABSTRACT FROM AUTHOR]

Network structured carbonized bacterial cellulose-supported Ru nanoparticles (CBC/Ru), which provide sufficient space for Li2O2 deposition without a significant volume effect and improve the transport of oxygen and electrons, were used as the binder-free oxygen electrode in a Li–O2 battery. The CBC/Ru exhibited high activities and good stability during discharge–recharge processes. [ABSTRACT FROM AUTHOR]

A new restriction effect of hard templates for the shrinkage of mesoporous polymer results in anomalous increase of the mesopore size during carbonization. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous SiO2, anatase TiO2 and cassiterite SnO2 hollow spheres have been successfully prepared using hydrophilic colloidal carbon spheres as template in conjunction with the sol–gel method. The hollow spherical structures could be confirmed by TEM and SEM. The void sizes of these hollow spheres were about 60% smaller than the diameters of the template. The BET surface areas of hollow spheres were about 183.8, 32.5, and 74.3 m2/g, respectively. [Copyright &y& Elsevier]

Review: 285 refs. [ABSTRACT FROM AUTHOR]

As promising candidates of power resources, electrochemical energy storage (EES) devices have drawn more and more attention due to their ease of use, environmental friendliness, and high transformation efficiency. The performances of EES devices, such as lithium-ion batteries, sodium-ion batteries, and supercapacitors, depend largely on the inherent properties of electrode materials. On account of the outstanding properties of graphene, a lot of studies have been carried out on two-dimensional (2D) materials. Over the past few years, a new exfoliation method has been utilized to successfully prepare a new family of 2D transition metal carbides, nitrides, and carbonitrides, termed MXene, from layered precursors. Moreover, some unique EES properties of MXene have been discovered. With rapid research progress on this field, a timely account about the applications of MXene in the EES fields is highly necessary. In this article, the research progress on the preparation, electrochemical performance, and mechanism analysis of MXene is summarized and discussed. We also propose some personal prospects for the further development of this field. [ABSTRACT FROM AUTHOR]

The paper describes a nonenzymatic amperometric HO sensor that uses a nanocomposite consisting of CoO nanoparticles (NPs) and mesoporous carbon nanofibers (CoO-MCNFs). The CoO NPs were grown in situ on the MCNFs by a solvothermal procedure. The synergetic combination of the electrocatalytic activity of the CoO NPs and the electrical conductivity of MCNFs as an immobilization matrix enhance the sensing ability of the hybrid nanostructure. The oxidation current, best measured at 0.2 V (vs. SCE) is linear in the 1 to 2580 μM HO concentration range, with a 0.5 μM lower detection limit (at an S/N ratio of 3). The sensor is highly selective even in the presence of common electroactive interferents. It was applied to the determination of HO in spiked milk samples. [ABSTRACT FROM AUTHOR]

β-SiC is a suitable photocatalyst for hydrogen evolution reaction because of its proper band structure (2.36 eV) and high chemical stability. Porousβ-SiC has a large surface area that can increase the number of reactive sites and shorten the charge transport pathways between the material interior and surface, thereby significantly improving the hydrogen evolution reaction performance. In the present study, hierarchical macroporousβ-SiC monolith composed of nanocrystals was directly prepared using SiO2opal as both template and precursor via the magnesiothermic reduction method at 750 °C. An interfacial magnesiothermic reaction model was presented as well. Theβ-SiC sample exhibited high photoelectric conversion performance and stability as a catalyst for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Nano and single‐atom catalysis open new possibilities of producing green hydrogen (H2) by water electrolysis. However, for the hydrogen evolution reaction (HER) which occurs at a characteristic reaction rate proportional to the potential, the fast generation of H2 nanobubbles at atomic‐scale interfaces often leads to the blockage of active sites. Herein, a nanoscale grade‐separation strategy is proposed to tackle mass‐transport problem by utilizing ordered three‐dimensional (3d) interconnected sub‐5 nm pores. The results reveal that 3d criss‐crossing mesopores with grade separation allow efficient diffusion of H2 bubbles along the interconnected channels. After the support of ultrafine ruthenium (Ru), the 3d mesopores are on a superior level to two‐dimensional system at maximizing the catalyst performance and the obtained Ru catalyst outperforms most of the other HER catalysts. This work provides a potential route to fine‐tuning few‐nanometer mass transport during water electrolysis. [ABSTRACT FROM AUTHOR]

Nano and single‐atom catalysis open new possibilities of producing green hydrogen (H2) by water electrolysis. However, for the hydrogen evolution reaction (HER) which occurs at a characteristic reaction rate proportional to the potential, the fast generation of H2 nanobubbles at atomic‐scale interfaces often leads to the blockage of active sites. Herein, a nanoscale grade‐separation strategy is proposed to tackle mass‐transport problem by utilizing ordered three‐dimensional (3d) interconnected sub‐5 nm pores. The results reveal that 3d criss‐crossing mesopores with grade separation allow efficient diffusion of H2 bubbles along the interconnected channels. After the support of ultrafine ruthenium (Ru), the 3d mesopores are on a superior level to two‐dimensional system at maximizing the catalyst performance and the obtained Ru catalyst outperforms most of the other HER catalysts. This work provides a potential route to fine‐tuning few‐nanometer mass transport during water electrolysis. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) carbonaceous aerogel derived from biomass bacterial cellulose (BC) is introduced as a flexible framework for iron oxides in Li-ion batteries (LIBs). The 3D carbonized BC (CBC) with highly interconnected nanofibrous structure exhibits good electrical conductivity and mechanical stability. The amorphous Fe 2 O 3 is tightly coated on the nanofibers of CBC through a simple in situ thermal decomposition method. The obtained amorphous Fe 2 O 3 anode (denoted as A-Fe 2 O 3 @CBC) exhibits stable cycling performance and high rate capability when assembled into a half-cell, which is supposed to benefit from the well-dispersed Fe 2 O 3 nanoshells and the hierarchical pores in A-Fe 2 O 3 @CBC composite. The rational design of the nanostructure could improve the transportation of electrons/ions and effectively alleviate volume changes of Fe 2 O 3 during the electrochemical cycling. Meanwhile, the amorphous nature of the Fe 2 O 3 in anode provides an enhanced capacitive-like lithium storage and flexible structure of the active materials, resulting in much higher specific capacity and longer cycle life when compared with its crystalline counterpart. This work provides a promising approach to design and construct the flexible metal oxide anode materials based on 3D carbonaceous aerogel for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Graphene–SnO2 nanocomposite was rapidly synthesized by a microwave-assisted method without using any additive. The as-prepared nanocomposite exhibits excellent electrochemical performance for lithium-ion batteries. Results show that the graphene–SnO2 nanocomposite with 70wt% SnO2 content exhibits a stable capacity of about 890mAhg−1 without noticeable fading for up to 80 cycles at a current density of 500mAg−1. Even when cycled at a high current density of 1000mAg−1, the specific capacity still remains approximately 790mAhg−1. The good electrochemical performance can be attributed to the porous structure of the nanocomposite and the restriction effect of graphene on the volume change of SnO2 nanoparticles. [Copyright &y& Elsevier]

Highly dispersed Pt nanoparticles were formed in the mesoporous channels of SBA-15 via direct low-temperature decomposition of H2PtCl6·6H2O by an improved solid–liquid route. During the preparation, solid H2PtCl6·6H2O turned into liquid and infiltrated the channels of SBA-15 when the temperature was above its melting point. The reaction process was analyzed by different characterizations. The results show that the solid intermediate phase, PtCl2, could not flow and assemble in the mesoporous channels during the heat-treatment; thus, it transformed into dispersed Pt nanoparticles after the reaction. Furthermore, as a nanoreactor, the mesoporous system had a nano-confinement effect on the low-temperature formation of Pt. [ABSTRACT FROM AUTHOR]

Hierarchically micro-/nanostructured coordination polymer[Cu(2,5-PDC)H2O]narchitectureswith tunablemorphologies have been successfully prepared by rationally adjustingthe preparation parameters, such as the reactant concentration, solvent,surfactant, and reaction temperature. Using simple calcinations ofchosen shaped [Cu(2,5-PDC)H2O]narchitectures, we can obtain several porous copper-based inorganicmotifs, which show potential applications for the antibacterial fieldand lithium ion batteries. Therein, CuO-1 can kill the Gram-positivebacteria Bacillus subtilis and Staphylococcus aureusbetter than other materials. The value for initial discharge capacityof CuO-3 (1160 mAh g–1) is higher than the theoreticalcapacity (674 mAh g–1) and most copper oxide materials.Besides, Cu/C composites also show intense application in the antibacterialand Li-ions uptake-release field, which will provide a widely usedmethod to prepare the nanosystem of carbon-coating or carbon-compositingmaterials by simple calcinations of shaped precursor coordinationpolymer particles used under the proper temperature. [ABSTRACT FROM AUTHOR]

Abstract: A MnO nanoparticle/graphene composite was prepared via in situ carbothermal reduction of Mn3O4 on the surface of graphene nanosheets. The formed MnO nanoparticles with diameters ranging from 20nm to 250nm integrated tightly with the graphene nanosheets. As anode material for lithium-ion batteries, the nanocomposite showed a high specific capacity of approximately 700mAhg−1 at 100mAg−1, excellent cyclic stability, and good rate capability. During the charge-discharge process, graphene nanosheets served as a three-dimensional conductive network for MnO nanoparticles. Furthermore, the detachment and agglomeration of MnO nanoparticles were effectively prevented due to the tight combination of MnO nanoparticles and graphene. [Copyright &y& Elsevier]

Abstract: Ordered mesoporous carbons (OMCs) with controllable pore sizes in the range of 4–10nm are prepared by a template procedure using 2D hexagonal MSU-H and 3D cubic KIT-6 as hard templates and boric acid as the pore expanding agent. The electrochemical performances of the as-synthesized OMCs as electrode materials for electrochemical double layer capacitors (EDLCs) are characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (GC) and electrochemical impedance spectroscopy (EIS) experiments in 30wt% KOH electrolyte. The influence of the pore size distributions of OMCs on the electrochemical capacitive performances is discussed. The prepared OMCs exhibit good capacitive behaviors with the specific capacitance values ranging from 143 to 205.3Fg−1 at a voltage scan rate of 5mVs−1 and 81 to 86% retained at a high scan rate of 100mVs−1. OMC-M-2 shows the highest specific surface capacitance value of 27.5μFcm−2 at 5mVs−1 with a peak pore size of 7.8nm and a Brunauer–Emmet–Teller (BET) surface area of 729.3m2 g−1. The analysis of two kinds of pore symmetries of OMCs with the same pore size of about 6.5nm shows that the 3D cubic OMC exhibited superior capacitive performance than the 2D hexagonal OMC. [Copyright &y& Elsevier]

Graphene-SnS nanocomposites were prepared via a solvothermal method with different loading of SnS. The nanostructure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD patterns revealed that hexagonal SnS was obtained. SEM and TEM results indicated that SnS particles distributed homogeneously on graphene sheets. The electrochemical properties of the samples as active anode materials for lithium-ion batteries were examined by constant current charge-discharge cycling. The composite with weight ratio between graphene and SnS of 1:4 had the highest rate capability among all the samples and its reversible capacity after 50 cycles was 351 mAh/g, which was much higher than that of the pure SnS (23 mAh/g). With graphene as conductive matrix, homogeneous distribution of SnS nanoparticles can be ensured and volume changes of the nanoparticles during the charge and discharge processes can be accomodated effectively, which results in good electrochemical performance of the composites. [ABSTRACT FROM AUTHOR]

Graphene is an excellent substrate to load nanomaterials for energy applications due to its large surface area, excellent conductivity, mechanical strength, and chemical stability. In this study, thermal exfoliated functionalized graphene sheets with good conductivity and high BET surface area are anchored with mesoporous NiO nanoplates by in situ chemical synthesis approach. Electrochemical characterization shows that functionalized graphene sheets-NiO sample exhibits a high capacity of about 700 mAh/g at a discharge current density of 100 mA/g and a good cycling ability. The high capacity and good cycling ability of functionalized graphene sheets -NiO material were attributed to the intimate interaction between the graphene sheets and NiO nanoplates. The graphene sheets not only enhance the conductivity of NiO nanoplates but also improve the structure stability of NiO nanoplates. Furthermore, the mesoporous structure of NiO nanoplates is available to the transfer of electrolyte. Such functionalized graphene sheets-NiO nanocomposite could be a promising candidate material for a high-capacity, low cost, and nontoxic anode for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: A mesoporous carbon nanofiber-modified pyrolytic graphite electrode (MCNF/PGE) has been prepared and applied to the simultaneous electrochemical determination of dopamine (DA), uric acid (UA) and ascorbic acid (AA). The oxidation overpotentials of these biomolecules decrease significantly, the overlapping of these peaks in bare PGE is well resolved, and their anodic peak currents increase dramatically in MCNF/PGE due to the large amount of edge-plane-like defects, large surface area and especially the mesoporous structure of MCNFs. Using this method, anodic currents of DA, UA and AA are linear with their concentration in the range of 0.05–30μM, 0.5–120μM and 0.1–10mM, respectively, with detection limits of 0.02, 0.2 and 50μM. The good sensitivity and reproducibility of the proposed electrode make it be used as a good electrochemical sensor for the simultaneous determination of DA, UA and AA in real sample analysis. [Copyright &y& Elsevier]

Abstract: New ordered mesoporous carbons containing nickel oxide nanoparticles have been successfully synthesized by carbonization of sucrose in the presence of nickel acetate inside SBA-15 mesoporous silica template. The obtained samples were characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, and transmission electron microscopy (TEM). The NiO nanoparticles were embedded inside the mesoporous carbon framework due to the simultaneous pyrolysis of nickel acetate during carbonization. The electrochemical testing of the as-made nanocomposites showed a large specific capacitance of 230Fg−1 using 2M KOH as the electrolyte at room temperature. This is attributed to the nanometer-sized NiO formed inside mesoporous carbons and the high surface area of the mesopores in which the NiO nanoparticles are formed. Furthermore, the synthetic process is proposed as a simple and general method for the preparation of new functionalized mesoporous carbon materials, for various applications in catalysis, sensor or advanced electrode material. [Copyright &y& Elsevier]

Abstract: ZnS nanodots highly dispersed on the surfaces of graphene sheets were successfully synthesized via an easy hydrothermal method by using Na2S as reducing agent as well as sulfide source. The reduction of graphite oxide (GO) to graphene was accompanied by the deposition of ZnS particles on the surface of graphene sheets. The results of X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) demonstrate the efficient reduction of GO to graphene sheets. The morphology characterization of the sample shows a wrinkled paper-like structure of the graphene sheets decorated with ZnS nanoparticles. Moreover, photoluminescence (PL) measurement shows a smooth spectrum, indicating fewer defects in the composite. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of the single-crystal Co3O4 nanorods by molten salt approach was reported for the first time. The products were characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM) and Selected-area electron diffraction (SAED). TEM results indicate that these nanorods have diameters of about 150 nm and lengths of about 2 μm. According to the analysis of the SAED and HRTEM results, we drew the conclusion that these nanorods grew along an unusual [−1,−1,15] direction by Ostwald ripening mechanism. [Copyright &y& Elsevier]

Designing and preparing kinetically stable metal–organic frameworks through ligand functionalization can effectively improve their supercapacitive performances. Herein, we have successfully synthesized a novel polythreaded Co-based MOF by choosing a flexible N-donor ligand and a rigid multicarboxylate linker, [Co(HTATB)(dib)]·2H2O (1), where dib is the flexible N-donor 1,4-di(1H-imidazol-1-yl)butane linker and HTATB is the deprotonation mode from 4,4′,4′′-s-triazine-2,4,6-triyl-tribenzoic acid. The bulk Co-MOFs crystals and the corresponding nanorod powders have been evaluated as electrode materials for supercapacitors. The maximum gravimetric capacitance of the nanorod electrode is 2405 F g−1 at 0.75 A g−1 in 4 M KOH, which is higher than 1 M and 6 M KOH solution and seven times larger than that of the bulk-crystal electrode. Furthermore, the nanorod electrode also exhibits excellent Coulombic efficiency (92.2%), rate capability (53.5% after 20 times increase) and good cycling performance (93.5% after 3000 continuous cycles). The excellent electrochemical property may be ascribed to the 3D networks constructed from 2D entangled layered structures facilitating electron transport, sufficient interlayer spaces available for the storage and diffusion of OH− ions, and the small-size effect of the nanorods. Further, the dye adsorption performance of crystalline 1 for methyl orange and Congo red has also been investigated. [ABSTRACT FROM AUTHOR]

Herein, hybrid Cu/Ni-based hexagonal rods were obtained through a competing reaction of dimethylglyoxime with copper acetate and nickel acetate. Using Cu2+ to intervene the coordination equilibrium between Ni2+ and dimethylglyoxime, the length of the rods was altered; moreover, the coordination environments were investigated by adjusting the concentration of Cu2+ and replacing the solvent. The decomposition products porous NiO and CuO/NiO were directly employed as SC electrodes. The CuO/NiO electrode delivered higher specific capacitance and energy with more excellent energy deliverable ability and better cycling stability than the pristine NiO electrode. After 2000 continuous cycles, the capacitance retention of the as-synthesized CuO/NiO electrode was 87.9%. The maximum specific capacitance and energy delivery efficiency of the CuO/NiO electrode were 344 F g−1 and 93.5%, respectively, at a current density of 0.625 A g−1. The better performance of the hybrid sample was mainly due to higher surface area, lower charge-transfer resistance, and possible synergistic effect. Furthermore, MgO/NiO nanoparticles were synthesized and compared to confirm the existence of a synergistic effect. [ABSTRACT FROM AUTHOR]

In this work, we report an ultrasensitive electrochemical biosensor for microRNA-21 (miRNA-21) detection by using a competitive RNA–RNA hybridization configuration. A biotinylated miRNA of the self-same sequence with the target miRNA is mixed with the samples, and allowed competition with the target miRNA for a thiolated RNA probe immobilized onto a tungsten diselenide (WSe2) nanosheet modified electrode. Thereafter the current response is obtained by forming the hybridized biotinylated miRNA with streptavidin–horseradish peroxidase (HRP) conjugates to catalyze the H2O2 + hydroquinone (HQ) system. Benefiting from the high specific surface area of WSe2 nanosheets, the competitive hybridization configuration and the signal amplification of the H2O2 + HQ detection system, the proposed assay exhibits a wide linear range of 0.0001–100 pM towards target miRNA with a detection limit of 0.06 fM (S/N = 3), and shows excellent discrimination ability for base-mismatched miRNA sequences. Therefore, the designed platform has promising prospects for the detection of miRNA in biomedical research and early clinical diagnosis. [ABSTRACT FROM AUTHOR]

Hydrogen sorption by reduced graphene oxides (r-GO) is not found to increase after decoration with Pd and Pt nanoparticles. Treatments of metal decorated samples using annealing under hydrogen or air were tested as a method to create additional pores by effects of r-GO etching around nanoparticles. Increase of Specific Surface Area (SSA) was observed for some air annealed r-GO samples. However, the same treatments applied to activated r-GO samples with microporous nature and higher surface area result in breakup of structure and dramatic decrease of SSA. Our experiments have not revealed effects which could be attributed to spillover in hydrogen sorption on Pd or Pt decorated graphene. However, we report irreversible chemisorption of hydrogen for some samples which can be mistakenly assigned to spillover if the experiments are incomplete. [ABSTRACT FROM AUTHOR]

Polypyrrole nanowires are facile synthesized under a mild condition with FeCl 3 as an oxidant. Polypyrrole nanowires with the width of 120 nm form many nanogaps or pores due to the intertwined nanostructures. More importantly, PPy nanowires were further applied for supercapacitor electrode materials. After electrochemical testing, it was observed that the PPy nanowire based electrode showed a large specific capacitance (420 F g −1 , 1.5 A g −1 ) and good rate capability (272 F g −1 , 18.0 A g −1 ), which is larger than that of most of published results. The as-prepared electrode can work well even after 8000 cycles at 1.5 A g −1 . [ABSTRACT FROM AUTHOR]

A template-free hydrothermal method is developed to prepare hierarchical hollow precursors. An inside-out Ostwald ripening mechanism is proposed to explain the formation of the hollow structure. After the calcination in the air, hierarchically meso/macroporous NaCoPO4-Co3O4 hollow microspheres can easily be obtained. When being evaluated as electrode materials for a supercapacitor, the hierarchically porous NaCoPO4-Co3O4 hollow microspheres electrode shows a specific capacitance of 268 F g−1 at 0.8 A g−1 and offers a good cycle life. More importantly, the obtained materials are successfully applied to fabricate flexible solid-state asymmetric supercapacitors. The device exhibits a specific capacitance of 28.6 mF cm−2 at 0.1 mA cm−2, a good cycling stability with only 5.5% loss of capacitance after 5000 cycles, and good mechanical flexibility under different bending angles, which confirms that the hierarchically porous NaCoPO4-Co3O4 hollow microspheres are promising active materials for the flexible supercapacitor. [ABSTRACT FROM AUTHOR]