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Metal–organic frameworks (MOFs) are highly regarded as valuable adsorbent materials in materials science, particularly in the field of CO2capture. While numerous single-metal-based MOFs have demonstrated exceptional CO2adsorption capabilities, recent advancements have explored the potential of bimetallic MOFs for enhanced performance. In this study, a CuCe-BTC MOF was synthesized through a straightforward hydrothermal method, and its improved properties, such as high surface area, smaller pore size, and larger pore volume, were compared with those of the bare Ce-BTC. The impact of the Cu/Ce ratio (1:4, 1:2, 1:1, and 3:2) was systematically investigated to understand how adding a second metal influences the CO2adsorption performance of the Ce-BTC MOF. Various characterization techniques, including scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N2BET surface area analysis, were employed to assess the physical and chemical properties of the bare Ce-BTC and CuCe-BTC samples. Notably, CuCe-BTC-1:2 exhibited superior surface area (133 m2g–1), small pore size (3.3 nm), and large pore volume (0.14 cm3g–1) compared to the monometallic Ce-BTC. Furthermore, CuCe-BTC-1:2 demonstrated a superior CO2adsorption capacity (0.74 mmol g–1), long-term stability, and good CO2/N2selectivity. This research provides valuable insights into the design of metal-BTC frameworks and elucidates how introducing a second metal enhances the properties of the monometallic Ce-BTC-MOF, leading to improved CO2capture performance.

Developing sustainable energy solutions to safeguard the environment is a critical ongoing demand. Electrochemical water splitting (EWS) is a green approach to create effective and long-lasting electrocatalysts for the water oxidation process. Metal organic frameworks (MOFs) have become commonly utilized materials in recent years because of their distinguishing pore architectures, metal nodes easy accessibility, large specific surface areas, shape, and adaptable function. This review outlines the most significant developments in current work on developing improved MOFs for enhancing EWS. The benefits and drawbacks of MOFs are first discussed in this review. Then, some cutting-edge methods for successfully modifying MOFs are also highlighted. Recent progress on nickel (Ni) and iron (Fe) based MOFs have been critically discussed. Finally, a comprehensive analysis of the existing challenges and prospects for Ni- and Fe-based MOFs are summarized.

Li7La3Zr2O12(LLZO)-based solid-state Li batteries (SSLBs) have emerged as one of the most promising energy storage systems due to the potential advantages of solid-state electrolytes (SSEs), such as ionic conductivity, mechanical strength, chemical stability and electrochemical stability. However, there remain several scientific and technical obstacles that need to be tackled before they can be commercialised. The main issues include the degradation and deterioration of SSEs and electrode materials, ambiguity in the Li+migration routes in SSEs, and interface compatibility between SSEs and electrodes during the charging and discharging processes. Using conventional ex situcharacterization techniques to unravel the reasons that lead to these adverse results often requires disassembly of the battery after operation. The sample may be contaminated during the disassembly process, resulting in changes in the material properties within the battery. In contrast, in situ/operandocharacterization techniques can capture dynamic information during cycling, enabling real-time monitoring of batteries. Therefore, in this review, we briefly illustrate the key challenges currently faced by LLZO-based SSLBs, review recent efforts to study LLZO-based SSLBs using various in situ/operandomicroscopy and spectroscopy techniques, and elaborate on the capabilities and limitations of these in situ/operandotechniques. This review paper not only presents the current challenges but also outlines future developmental prospects for the practical implementation of LLZO-based SSLBs. By identifying and addressing the remaining challenges, this review aims to enhance the comprehensive understanding of LLZO-based SSLBs. Additionally, in situ/operandocharacterization techniques are highlighted as a promising avenue for future research. The findings presented here can serve as a reference for battery research and provide valuable insights for the development of different types of solid-state batteries.

Metal tellurides (MTs) have emerged as highly promising candidate anode materials for state-of-the-art lithium-ion batteries (LIBs) and sodium ion batteries (SIBs). This is owing to the unique crystal structure, high intrinsic conductivity, and high trap density of such materials. The present work delivers a detailed discussion on the latest research and progress associated with the use of MTs for LIBs/SIBs with a focus on reaction mechanisms, challenges, electrochemical performance, and synthesis strategies. Further, the prospects and future development of MT anode materials are discussed in terms of strategies to overcome the existing limitations. This review provides both an in-depth understanding of MTs and provides the driving force for expanding research on MTs for energy storage and conversion applications.

The working mechanisms, cathode design, recent progress and challenges of oxide-based cathodes for zinc ion batteries (ZIBs) are systematically reviewed.

Lanthanide-doped upconversion nanoparticles (UCNPs) have unique photoluminescent properties that are useful in many biomedical applications. Modification of UCNPs with a polymer layer can confer additional functionality such as biocompatibility, stability in vivo, or drug delivery capability. It is also important that the modification process can be controlled precisely and without having adverse effects on the UCNPs luminescence properties. Herein, a polymer shell was grafted directly from the surface of UCNPs (grafting from) via visible light (λmax= 635 nm, 0.7 mW/cm2) regulated photoenergy/electron transfer–reversible addition fragmentation chain transfer polymerization (PET-RAFT). The polymerization kinetics, grafting density, and thickness of the surface-tethered polymer chains can be tuned precisely by adjusting the monomer and RAFT agent ratio or the light exposure time. This approach also permits temporal control of the polymerization process. That is, the polymerization process can be initiated, halted, or terminated by switching the light source on and off. By limiting the non-radiative decay caused by surface defects, as well as from vibrational deactivation from solvents, the polymer shell enhanced the upconversion luminescence of the silica-coated UCNPs. This investigation paves the way for the development of UCNPs with controlled properties for various application requirements.

This study is focused on the synthesis of a solar light driven novel poly(vinyl alcohol) (PVA)-assisted TiO2/Ti film via a facile one pot hydrothermal technique and then its photocatalytic applications by adding with peroxymonosulfate (PMS) for efficient degradation of ciprofloxacin (CIP). The key hydrothermal synthesis parameters like PVA-content, hydrothermal time (HT), and pH were optimized. The best photocatalytic performance of the synthesized material was observed when prepared with the conditions of PVA = 8 mg, HT= 3 h, and pH = 2.62. Results showed that 98.3% of CIP was degraded within 60 min by PVA-assisted TiO2/Ti film with 0.5 mM PMS added, compared to 89.38% and 88.86% degradation with 0.5 mM persulfate (PS) and 0.5 mM hydrogen peroxide (H2O2), respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added was dependent on the [PMS]0and increased with increase in [PMS]0. The kappvalues at [PMS]0of 0.2, 0.5, 0.8, and 1.0 mM were 0.029, 0.0582, 0.068, and 0.128 min–1, respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation was highly dependent on the [pH]0as well as on the presence of coexisting anions like HCO3–, CO32–, NO2–, Cl–, and SO42–. Natural organic matter (NOM) retarded the photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation due to its strong scavenging ability toward •OH and SO4•–. The photocatalytic degradation of CIP by as-prepared photocatalyst under solar light irradiation was higher in Milli-Q water (kapp= 0.0582 min–1) than tap water (kapp= 0.0342 min–1) followed by river water (kapp= 0.0259 min–1) and then synthetic wastewater (kapp= 0.0212 min–1). The degradation products of CIP were investigated by UPLC-MS/MS, and accordingly degradation pathways were proposed. Moreover, the mineralization, ecotoxicity, and cyclic photocatalytic stability of the as-prepared photocatalyst were also investigated. These findings suggest that as-prepared PVA-assisted TiO2/Ti film with PMS added is a promising alternative for the treatment of wastewater containing antibiotics.

The application of modified transition metal telluride electrodes through (defect, compositing, and phase) engineering, including main cobalt telluride and (iron, nickel, zinc, copper, molybdenum, titanium) telluride in metal (Li, Na, K, Al)-ion batteries, lithium-sulfur and lithium-tellurium batteries, as well as aqueous zinc-ion batteries have been summarized.

Abstract: In recent years, Nb-based oxides, especially Nb2O5, due to their unique structural advantages, have stimulated scholars’ extensive research enthusiasm in the field of energy storage systems including lithium ion batteries (LIBs) and sodium ion batteries (SIBs), excellent chemical stability and outstanding rate capability dominated by pseudocapacitive nature. In addition, Nb-based oxides usually have a higher operating voltage (> 1.0 V vs Li+/Li), which can effectively prevent the decomposition of organic electrolytes and the formation of solid electrolyte interface films in batteries. This review systematically summarizes the different crystal structures of Nb2O5and the lithium storage mechanism based on theoretical calculations, as well as the comparison of various synthesis strategies. In addition, the advanced research progress of niobium-based oxides as anode materials in LIBs and SIBs is summarized from the perspective of nanostructure control engineering that affects electrochemical performance. It also puts forward reasonable cognition and challenges for future research, which is conducive to the design of energy storage equipment that meets the needs of sustainable development. Graphic abstract: The design and optimization of various synthesis methods facilitate the formation of a variety of heterogeneous nanostructures, leading to reversible storage of Li and Na ions.

Porous materials have emerged as promising candidates for electrocatalytic water splitting due to their abundant reaction sites, interconnected diffusion channels, and facile gas bubble dissipation. The presence of surface defects on electrocatalysts promotes conductivity and diffusion coefficient, thus improving electrochemical performance. Here, an efficient way is described for generating defect-rich, highly ordered macroporous phosphorus-doped cobalt oxides catalysts (Co:Pi/CoOx/CP) by an in situ template assembly strategy followed by a fast microwave-induced plasma (MIP). The obtained three-dimensional (3D) Co:Pi/CoOx/CP exhibits an ordered honeycomb-like porous structure with superhydrophilicity, high surface area, and abundant surface defects, and is highly active for catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In situ Raman and ex situ spectroscopic and microscopic characterizations reveal a large number of surface defects and cobalt phosphate formation induced by MIP and elucidate their significant effects on the excellent catalytic performance of 3D Co:Pi/CoOx/CP.

Ammonia is a key industrial raw material for fertilisers, chemicals and energy. The annual artificial ammonia synthesis viathe Haber–Bosch process results in about 2% of global energy consumption and can lead to 1.6% CO2emission. Hence, it is urgent to develop low-cost and environmentally friendly approaches for artificial ammonia synthesis under ambient conditions. Recently, bismuth (Bi)-based catalysts have attracted great interest due to their excellent nitrogen fixation performance in electrochemical and photocatalytic fields. However, there is still a lack of a comprehensive review on Bi-based nitrogen-fixation materials focusing on their crystal structure, surface engineering and modification methods, which is highly desirable for facilitating their further development towards applications. Herein, we provide an up-to-date review on Bi-based nitrogen-fixation materials and classify them as metallic Bi, bismuth oxide, bismuth oxyhalide, and Bi-based polyoxometalates. Starting from the underlying crystal structure, we analyse the internal electric field, surface engineering and modification methods of Bi-based nitrogen fixation materials. Then, we highlight the latest achievements of Bi-based materials and reveal the challenges and obstacles in the development and application of Bi-based nitrogen-fixation materials. More importantly, this review presents the surface and structure engineering strategies, and future directions for the development of new Bi-based nitrogen-fixation materials under ambient conditions.

Perovskite solar cells (PSCs) are now crossing the certified 23.2% power conversion efficiency (PCE), however, the stability of organic-lead halide perovskites, cost of additives doped hole transport layer (HTL) and upscaling from lab-scale to industrial scale without hampering its efficiency are challenging tasks for its commercial application. These problems could be tackled via different aspects which includes the synthesis of promising electron transport layers (ETLs) and HTLs, synthesis of mixed perovskites via combination of 3D and stable 2D perovskite, replacement of poor-stable methylammonium (MA) cation with MA free perovskite and capping inorganic materials will be the best choice toward highly efficient air-thermal-stable perovskite solar cells (PSCs). This perspective focuses on the current strategies in PSCs for making the stable PSCs via low-cost, easily processed components and shared our views toward commercialization.

To understand the fundamental aspects of SnO2catalytic materials and develop applicable catalysts for VOCs combustion, SnO2samples possessing stable and varied surface areas are controllably constructed and applied to toluene deep oxidation. By improving SnO2surface area, the Sn4+cation exposure is improved, thus increasing its surface acidity, which benefits toluene molecule adsorption and activation. Furthermore, more surface defects can be generated, hence inducing the generation of more abundant surface active oxygen sites, which is favorable for further oxidizing the adsorbed and activated toluene intermediates. Therefore, the intrinsic activity of SnO2is eventually promoted. The coexistence of both kinds of active sites is crucial for the reaction, and the concerted interaction between them controls the reaction performance. Catalysts with good activity, superior stability, and potent water vapor tolerance can be achieved by controllably constructing SnO2possessing large and stable surface areas, and supporting less amount of Pd onto it.

Thermocatalytic CO2hydrogenation is a scalable route to renewable fuels and chemicals that can also mitigate climate change. Here, we demonstrate how subtle changes in a mixed phase zirconia support induce large changes in catalyst activity and selectivity. Ru/SnxZr1-xO2catalysts were prepared using co-precipitated Sn-doped ZrO2. Ru/ZrO2and Ru/Sn0.01Zr0.99O2both comprised tetragonal (t-) and monoclinic (m-) ZrO2nanoparticles decorated by RuO2·H2O clusters. Ru/Sn0.2Zr0.8O2exhibited similar textural properties and metal speciation, however, X-ray diffraction evidenced new crystalline phases wherein Sn atoms substituted for Zr. Operando XRD evidenced minimal perturbation of ZrO2and Sn-doped ZrO2phases, despite which 20 atom% Sn switched product selectivity from 99% CH4for Ru/ZrO2to 67% CO for Ru/Sn0.2Zr0.8O2, due to increased support CO2adsorption capacity/strength. Operando infrared spectroscopy identify linear surface CO* as a catalytic spectator with (bi)carbonate a precursor to reactive HCOO*/carboxylate intermediates to methane. Sn0.2Zr0.8O2promotes CO2/(bi)carbonate/formate decomposition, favouring a reverse water gas shift pathway.

A comprehensive and categorized review on performances of various phosphate adsorbents, especially those that emerged in last decade, is presented.

Mesoporous metals with high surface area hold promise for a variety of catalytic applications, especially for the reduction of CO2to value-added products. This study has used a novel mesoporous rhodium (Rh) nanoparticles, which were recently developed via a simple wet chemical reduction approach (Nat. Commun.2017, 8, 15581) as catalyst for CO2methanation. Highly efficient performance and selectivity for methane formation are achieved due to their controllable crystallinity, high porosity, high surface energy, and large number of atomic steps distributions. The mesoporous Rh nanoparticles, possessing the largest surface area (69 m2g–1), exhibit a substantially higher reaction rate (5.28 × 10–5molCO2gRh–1s–1) than the nonporous Rh nanoparticles (1.28 × 10–5molCO2gRh–1s–1). Our results indicate the extensive use of mesoporous metals in heterogeneous catalysis processes.

Unique CO2methanation catalysts comprising bimetallic Ni–Rh nanoalloy/3DOM LaAlO3have been successfully prepared via a poly(methyl methacrylate) microsphere colloidal crystal-templating route, followed by the in situ growth of Ni nanoparticles (NPs). Here, we show that unlike traditional Ni particles deposited on a perovskite support, the exsolution of Ni occurs on both the external and internal surface of the porous perovskite substrate, leading to a strong metal–support interaction. Owing to the exsolution of Ni and the formation of Ni–Rh nanoalloys, a 52% enhancement in the methanation turnover frequency was obtained over the Ni–Rh/3DOM LaAlO3[13.9 mol/(mol h)] compared to Rh/3DOM LaNi0.08Al0.92O3[9.16 mol/(mol h)] before reduction treatment. The results show that the low-temperature reducibility, rich surface adsorbed oxygen species, and basic sites of the catalyst greatly improve its activity toward CO2methanation. The hierarchically porous structure of the perovskite support provides a high dispersion of bimetallic Ni–Rh NPs.

Novel S-doped Fe2O3/C nanocomposite was synthesized via a one-pot hydrothermal method and was used for the first time as an efficient adsorbent for Congo red dye (CR) removal from water solution. The obtained catalyst was characterized by various methods including Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometry, vibration sample magnetometry, X-ray diffraction and field emission scanning electron microscopy. To improve the adsorption performance, some important parameters affecting dye removal were optimized such as adsorbent dosage, contact time, solution pH, initial dye concentration and ionic strength. At the optimum conditions, the maximum capacity of adsorption for this nanocomposite was 270.2 mg g−1, which is better than other magnetic adsorbents for CR removal. The results of adsorption isotherm were matched with Langmuir model. Kinetic tests show that adsorption experimental data were best fitted by pseudo-first-order model.

The effects of Zn-doping on CeO2nanocrystals were investigated for the catalytic oxidation of carbon monoxide (CO). Incorporating Zn2+into CeO2nanocubes with an isotropic 3D structure can effectively regulate oxygen vacancy concentration, compared with CeO2nanorods showing an anisotropic one dimensional 1D structure. The catalytic activity was shown to be governed by a morphology-dependent doping effect.

The Pd-based catalysts have been widely studied for the combustion of volatile organic compounds, in which the roles of the Pd and the support are still not known clearly. In this study, mesoporous Co3O4and CoO (i.e., meso-Co3O4and meso-CoO) were prepared and used as support for the loading of Pd nanoparticles (NPs). The supported Pd samples performed much better than the supports for o-xylene combustion, in which the Pd/meso-CoO sample showed the best catalytic activity (T90%= 173 °C), giving rise to reaction rates at 170 °C 3.5 and 84 times higher than those over the Pd/meso-Co3O4and meso-CoO samples, respectively. It has been established that the meso-CoO sample possessed strong ability to activate oxygen molecules to the active oxygen species, the loaded Pd NPs in a metallic Pd phase was beneficial for o-xylene adsorption, and the adsorbed o-xylene species could immediately react with the active oxygen species at the interface between Pd NPs and meso-CoO. Therefore, we conclude that the excellent catalytic performance of the Pd/meso-CoO sample was associated with its highly active Pd–CoO interface.

Ordered mesoporous silicas are important technological materials in catalysis, sorption and separation science, however new architectures are desired to improve in-pore accessibility. Here we report the first synthesis of an ordered macroporous KIT-6, obtained by optimizing the ratios of Pluronic P123: sodium dodecyl sulfate cosurfactants, and a 400 nm polystyrene nanosphere macropore template. The macroporous KIT-6 possesses 370 nm macropores in a face-centered cubic arrangement, surrounded by a silica framework comprised of cubic Ia3¯dthree-dimensional, intertwined 5 nm mesopore channels. Propylsulfonic acid (PrSO3H) functionalization affords a macroporous KIT-6 solid acid catalyst whose hierarchical pore network permits rapid diffusion and esterification of fatty acids, conferring a five-fold enhancement for palmitic acid esterification compared with a conventional mesoporous PrSO3H/KIT-6, and 33% rate enhancement vs. an ordered macroporous PrSO3H/SBA-15.

As an alternative to H2O2enzymatic biosensing devices, non-enzymatic CeO2-based biosensors have shown improved sensibility, robustness, and shelf lives. The redox capability in CeO2and rapid switching between its oxidation states facilitate the formation of structural vacancy defects that serve as active sites. This work reports a novel approach for synthesis of defect-rich CeO2-x-based nanoflakes using a controllable electrochemical-based deposition at low temperatures (45°−65 °C) followed by low-energy ion implantation. Among the nanoflakes, Mo-implanted CeO2-xexhibited outstanding sensitivity of 4.96 × 10−5 A·mM−1cm−2within the linear range of 0.05–10 mM. Moreover, the ion-implanted samples yielded high sensing stability and electronic conductivity. The former was achieved through the multi-valence charge transfer between Ce and the implanted ions that caused the reduction of Gibbs free energies required for the formation/retention of the defects. The latter was due to the narrowing of the electronic bandgap of CeO2-xby creation of defect-induced midgap states.

We report a scalable method to obtain a new material where large graphene sheets form webs linking carbon fibers. Film-fiber hybrid nonwoven mats are formed during fiber processing and converted to carbon structures after a simple thermal treatment. This contrasts with multistep methods that attempt to mix previously prepared graphene and fibers, or require complicated and costly processes for deposition of graphene over carbon fibers. The developed graphene–fiber hybrid structures have seamless connections between graphene and fibers, and in fact the graphene “veils” extend directly from one fiber into another forming a continuous surface. The graphene–fiber hybrid structures are produced in situ from aqueous poly(vinyl alcohol) solutions. The solutions were subjected to centrifugal spinning to produce fine nanofiber mats. The addition of salt to the polymer solution stimulated a capillarity effect that promoted the formation of thin veils, which become graphene sheets upon dehydration by sulfuric acid vapor followed by carbonization (at relatively low temperatures, below 800 °C). These veils extend over several micrometers within the pores of the fiber network, and consist of crystalline graphene layers that cross-link the fibers to form a highly interconnected hybrid network. The surface area and pore diameter of the hybrid structures were measured to be 521 m2g–1and 10 nm, respectively. The resulting structure shows high electrical conductivity, 550 S/m, and promising shielding of electromagnetic interference, making it an attractive system for a broad range of electronic applications.

Gamma alumina is one of the widely used supports in catalyst preparation, possessing a high specific surface area and good thermal stability. Spray drying is an efficient way to produce narrow particle size distribution and spherical shape powders. In this study, spray drying method has been implemented to prepare microspherical nanoporous gamma alumina with a high specific surface area. The nanoporous gamma alumina support was utilized in the preparation of various heterogeneous base catalysts. The highest biodiesel yield of 99% was obtained at 6 wt% loading of K/γ-Al2O3catalyst, using waste cooking oil as feedstock. The obtained results revealed the great potential of the synthesized nanoporous gamma alumina as an effective support for heterogeneous base catalysts preparation in the transesterification reaction.

Total rock porosity is a key parameter in a wide range of disciplines from petroleum to civil and mining engineering. Porosity is particularly important in petroleum engineering applications, e.g., from estimation of hydrocarbon in place to prediction of geomechanical properties. Conventional techniques used to measure the total porosity, i.e., mercury intrusion, nitrogen physisorption, focused ion beam–scanning electron microscopy (FIB–SEM), nuclear magnetic resonance (NMR) spectroscopy, gas porosimetry, and X-ray micro-/nano-computed tomography (micro-CT), have yielded inconsistent results for unconventional shale gas samples. A new robust yet practical method is thus required for measuring total porosity in tight formations to be added to the toolbox of the porosity measurement. We propose and develop here a new technique using the concept of heat transfer in porous media. This new heat technique route (HTR) was tested on a highly homogeneous Gosford sandstone benchmark to evaluate its reliability and repeatability in estimation of the total porosity. An excellent agreement was found with the conventional mercury intrusion, gas porosimetry, and micro-CT imaging techniques. Subsequently, the total porosity of an organic-rich shale sample was measured using the HRT method and compared to the conventional techniques of nitrogen physisorption–mercury intrusion and FIB–SEM techniques. Finally, a Monte Carlo analysis was performed on heat transfer measurements, proving its robustness for total porosity measurements.

Through effectively harvesting and converting solar energy, photocatalysis has become one of the most important technologies in wastewater decontamination and hydrogen production. Currently, extensive studies are being conducted to develop photocatalysts with advanced features, such as visible-light response, heterogeneous nanoarchitecture, plasmonic effect, and excellent optical behavior. Finding efficient utilization technique to improve photocatalytic performance motivates researchers all over the world. Herein, we demonstrate the design of a visible-light-driven Pd/Fe2O3/BiVO4hybrid with 3D ordered macro-/mesoporous (3DOM) nanoarchitecture for efficiently photocatalytic organic degradation and photoelectrochemical (PEC) water splitting. The hybrid photocatalyst exhibited two-tier bandgap energies and possessed enhanced ability to harvest visible light and separate photo-induced carriers. It is shown that, over the Pd/Fe2O3/3DOM-BiVO4photocatalyst, not only the refractory phenol could be rapidly degraded into CO2and H2O, but also the photoconversion efficiency was greatly improved in water splitting to generate H2. The excellent photocatalytic performance of Pd/Fe2O3/BiVO4was associated with the construction of low-crystalline plasmonic heterointerfaces through the 3DOM framework. The produced synergistic action enabled the hybrid material to absorb the sunlight adequately and transfer the photoexcited carriers expediently to drive phenol degradation or hydrogen evolution from water.

Newly designed 3D highly ordered macro/mesoporous multifunctional La1–xCexCoO3nanohybrid frameworks with a 2D hexagonal mesostructure were fabricated via facile meso-molding in a three-dimensionally macroporous perovskite (MTMP) route. The nanohybrid framework exhibited excellent catalytic activity for methane combustion, which derived from the MTMP providing a larger surface area and pore volume, uniform pore sizes, higher accessible surface oxygen concentration, better low-temperature reducibility, and a unique nanovoid 3D structure.

This study presents an optimization of dehydrogenation catalyst components including platinum, indium, and lithium using response surface methodology (RSM). The catalysts were supported on a synthesized nanocrystalline gamma alumina and evaluated in the dehydrogenation reaction of higher normal paraffins (C10–C15). The best catalytic performance was obtained with the following material ratios: 0.22 of Pt, 0.5 of In, and 0.31 of Li. Comparison of the performance of the optimized catalyst to an industrial catalyst showed the improved catalytic activity of the optimized sample. The obtained results revealed the excellent potential of the optimized catalyst in the dehydrogenation reaction of higher normal paraffins.

Piezocatalysis is capable of converting mechanical vibrations into chemical energy, portraying a promising alternative technology for hydrogen peroxide (H2O2) production. Environmentally benign lead-free barium titanate piezocatalyst has received particular attention due to its ferroelectric property. However, the reported H2O2yield is not ideal and one of the reasons is the undesirable piezoelectricity. Herein, a series of lead-free perovskite oxides consisting of (1-x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3solid solutions are developed for H2O2production by introducing more favorable crystal phases to increase the piezoelectricity. The prepared perovskite oxides were characterized by significantly enhanced piezoeletricities owing to the coexistence of the ternary (orthorhombic, tetragonal and rhombohedral) phases with reduced energy barrier for polarization rotation. Benefiting from the notably improved piezoelectric property and appropriate oxygen vacancy concentration, the optimal composition of 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3exhibits an outstanding H2O2selective generation and long-lasting stability. Under ultrasonic irradiation, a superior H2O2yield of 692 µmol g-1h-1with a selectivity of 80% was attained, showing the enhancement by the factors of 3.3, 4.1 and 8.7 compared to Ba0.7Ca0.3TiO3, BaZr0.2Ti0.8O3and BaTiO3, respectively. Furthermore, the catalyst is highly stable by delivering a H2O2productivity of 3313 µmol g-1in 14 h of piezocatalysis. Mechanism study suggests that H2O2generation stems from an efficient O2reduction via a two-electron transfer pathway, during which the piezopotential is of primary importance to provide driving force for the carrier separation and transportation. Moreover, the green and non-toxic piezocatalysis system based on the BaCaZrTi solid solutions can be applied for efficient water disinfection. This study offers guidance towards the rational design of lead-free piezocatalyst and reaction system for H2O2generation and its application.

A series of Ag nanoparticles (NPs) supported on three-dimensionally ordered macroporous (3DOM) La0.6Sr0.4MnO3(yAg/3DOM La0.6Sr0.4MnO3; y= 0, 1.57, 3.63, and 5.71 wt %) were successfully prepared with high surface areas (38.2–42.7 m2/g) by a facile novel reduction method using poly methacrylate colloidal crystal as template in a dimethoxytetraethylene glycol (DMOTEG) solution. Physicochemical properties of these materials were characterized by means of numerous techniques, and their catalytic activities were evaluated for the combustion of methane. It is shown that the yAg/3DOM La0.6Sr0.4MnO3materials possessed unique nanovoid-like 3DOM architectures, and the Ag NPs were well dispersed on the inner walls of macropores. Among the La1–xSrxMnO3(x= 0.2, 0.4, 0.6, 0.8) and yAg/3DOM La0.6Sr0.4MnO3(y= 0, 1.57, 3.63, and 5.71 wt %) samples, 3.63 wt % Ag/3DOM La0.6Sr0.4MnO3performed the best, giving T10%, T50%, and T90%(temperatures corresponding to methane conversion =10, 50, and 90%) of 361, 454, and 524 °C, respectively, and the highest turnover frequency (TOFAg) value of 1.86 × 10–5(mol/molAgs) at 300 °C. The apparent activation energies (39.1–37.5 kJ/mol) of the yAg/3DOM La0.6Sr0.4MnO3samples were much lower than that (91.4 kJ/mol) of the bulk La0.6Sr0.4MnO3sample. The effects of water vapor and sulfur dioxide on the catalytic activity of the 3.63 wt % Ag/3DOM La0.6Sr0.4MnO3sample were also examined. It is concluded that its super catalytic activity was associated with its high oxygen adspecies concentration, good low-temperature reducibility, large surface area, and strong interaction between Ag and La0.6Sr0.4MnO3as well as the unique nanovoid-walled 3DOM structure.

Abstract: The perovskite metal-oxides LaNi x Fe1−x O3 (0≤ x ≤1) were synthesized by a sol–gel method and investigated for the DR, POM, and CRM into synthesis gas. The catalysts were characterized by using XRD, BET, CA, SEM, EDS, HR-TEM, EDX and TPR in order to investigate the influence of the preparation parameters and evaluation condition. LaNi0.4Fe0.6O3 showed great stability, and fewer carbon deposits were detected on the spent catalyst after 1800min evaluation on TOS. The effect of GHSV on the catalytic performance was investigated. The results obtained showed the H2/CO molar-ratio was around 0.9, 1.7, and 1.1 over different catalysts for DR, POM and CRM, respectively. [Copyright &y& Elsevier]

A series of perovskite-type oxides catalyst LaAl1-xNixO3 (0=x=1) and modified by substitute noble metal La0.4Al0.2Ni0.8M0.6O3 (M=Pt, Pd, Ru, Rh, Ir) prepared by the sol-gel method shows high activity, stability, good resistance to carbon deposition and sintering of the catalyst for the reforming of methane reaction. The reaction was studied under continuous flow using a mixture of CH4:CO2=1:1. Catalysts were characterized by using BET, XRD, SEM, EDS, and HR-TEM. The specific surface area of catalysts varied greatly from 3.07 to 10.18 m2/g with the different substitution (x) following calcination at 850°C. XRD analysis of the solids shows LaNiO3 and/or LaAlO3 as the main phases present on the solids depending on the degree of substitution and more intense peaks and cell parameters showed formation of Ni-Al solid solutions. SEM coupled to an energy dispersive X-ray spectrometer (EDS) shows the possibility to obtain a solid solution of LaAl1-xNixO3 (0=x=1) with propionic acid as solvent. The obtained results revealed that the Rh and Ru catalysts showed the highest activity and also showed a high catalytic stability without any decrease in methane conversion up to 3000min of reaction.

A series of vanadium-doped CoCr2–xVxO4(x= 0–0.20) catalysts were prepared via the citric acid method and investigated for methane combustion. A significant improvement of the catalytic activity was observed over a CoCr1.95V0.05O4catalyst, and the catalytic activity reached 90% of methane conversion at 438 °C, which was 76 °C lower than that of the undoped catalyst. Vanadium doping caused disorder in the spinel structure and various changes in physicochemical properties. The higher concentration of suprafacial, weakly chemisorbed oxygen and the active cobalt species, especially Co3+, could play a major role in the oxidation reaction. Results of XRD, Raman, and XPS suggested that excess vanadium probably formed separate catalytically inactive VOxspecies, which would explain the decline of catalytic activity for samples with a higher substitution degree.