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Water electrolysis is a promising method for efficiently producing hydrogen and oxygen, crucial for renewable energy conversion and fuel cell technologies. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are two key electrocatalytic reactions occurring during water splitting, necessitating the development of active, stable, and low-cost electrocatalysts. Transition metal (TM)-based electrocatalysts, spanning noble metals and TM oxides, phosphides, nitrides, carbides, borides, chalcogenides, and dichalcogenides, have garnered significant attention due to their outstanding characteristics, including high electronic conductivity, tunable valence electron configuration, high stability, and cost-effectiveness. This timely review discusses developments in TM-based electrocatalysts for the HER and OER in alkaline media in the last 10 years, revealing that the exposure of more accessible surface-active sites, specific electronic effects, and string effects are essential for the development of efficient electrocatalysts towards electrochemical water splitting application. This comprehensive review serves as a guide for designing and constructing state-of-the-art, high-performance bifunctional electrocatalysts based on TMs, particularly for applications in water splitting. [ABSTRACT FROM AUTHOR]

The surface atomic arrangement and defective structures of electrocatalysts play a crucial role in determining their catalytic activity and selectivity. Hematite (α-Fe2O3) nanostructures with oxygen vacancies are promising electrocatalysts for the oxygen reduction reaction (ORR) due to their low-cost and environmental friendliness. However, a systematic study of their ORR performance, especially selectivity at high oxygen vacancy concentrations, is still lacking. In this study, we synthesized α-Fe2O3 nanosheets with surface oxygen vacancies using a simple solvothermal reaction followed by a liquid phase NaBH4 reduction method. The oxygen vacancy amount was adjusted by varying the concentrations of NaBH4 solution, and it was found that increasing the oxygen vacancy concentration from 11.4% to 43.4% improved the ORR activity, but further increasing it to 77.3% deteriorated the crystalline quality and thus affected the ORR performance. The optimized sample (α-Fe2O3-1 M), treated with a 1 M NaBH4 solution, showed a high limiting current density of 5.75 mA cm−2 at 0.4 V vs. the reversible hydrogen electrode (RHE). The observed enhancement in ORR activity can be attributed to the optimal surface oxygen vacancies, which improve catalytic kinetics and increase the exposure of active sites. [ABSTRACT FROM AUTHOR]

Transition metal oxide (TMO)‐based anodes attract much attention for lithium storage due to the merits of high theoretical capacity, facile synthesis, and easy scale‐up. Moreover, the increased working potential avoids the issue of lithium dendrites formation and thus improves battery safety. Herein, we propose a route to significantly improve the electrochemical performance of TMO anodes through configurational entropy optimization. For example, high‐entropy oxide (FeCoNiCrCu)3O4 is synthesized by carefully selecting metal elements. The (FeCoNiCrCu)3O4 electrode ensures not only low potential but also holds high capacity. In the half‐cell configuration, the (FeCoNiCrCu)3O4 electrode provides a specific capacity of 575.7 mAh g−1 after 200 cycles at 0.2 A g−1. More importantly, the electrode showed a relatively low discharge voltage of 0.39 V at 0.5 A g−1, which is caused by the configuration entropy optimization. The assembled (FeCoNiCrCu)3O4//LCO coin‐type full cell exhibits a high capacity of 266.3 mAh g−1 after 100 cycles at 0.2 A g−1 and an operating voltage up to 3.9 V. [ABSTRACT FROM AUTHOR]

This study aims to investigate the catalytic activity of spinel-type oxides (NixCoyO4) for the oxidation of toluene and carbon monoxide at low temperatures. A series of Ni/Co catalysts with different mole ratios were synthesized via citric acid assisted sol-gel method and the influence of the nickel to cobalt ratios on the properties and catalytic performance of NixCoyO4 were investigated by characterization such as XRD, SEM-EDX, BET, H2–TPR. The results indicate that the catalyst with the Ni/Co atomic ratio of 1.5/1.5 exhibits the highest complete toluene oxidation activity, with 85% toluene conversion rate at 100 – 250 °C and complete toluene oxidation at 300 °C. However, for the complete oxidation of CO, the Ni/Co atomic ratio of 1/2 exhibits higher activity, converting 100% CO at 150 °C. The results show that NiO and CoOx are proved to be more active than the other for the oxidation of toluene and CO, respectively. The characteristic results show that high surface area, small particle size, good temperature reducibility, and oxygen species with high mobility in low-temperature regions are responsible for the catalytic performance of nickel cobalt spinel-type catalyst for toluene and carbon monoxide oxidation. The good stability of the Ni-Co oxide catalysts for the oxidation reactions originates from the strong Ni-Co interaction. [ABSTRACT FROM AUTHOR]

Liquid phase transmission electron microscopy (TEM) provides a useful means to study a wide range of dynamics in solution with near-atomic spatial resolution and sub-microsecond temporal resolution. However, it is still a challenge to control the chemical environment (such as the flow of liquid, flow rate, and the liquid composition) in a liquid cell, and evaluate its effect on the various dynamic phenomena. In this work, we have systematically demonstrated the flow performance of an in situ liquid TEM system, which is based on ‘on-chip flow’ driven by external pressure pumps. We studied the effects of different chemical environments in the liquid cell as well as the electrochemical potential on the deposition and dissolution behavior of Cu crystals. The results show that uniform Cu deposition can be obtained at a higher liquid flow rate (1.38 ÎĽ l minâˆ'1), while at a lower liquid flow rate (0.1 ÎĽ l minâˆ'1), the growth of Cu dendrites was observed. Dendrite formation could be further promoted by in situ addition of foreign ions, such as phosphates. The generality of this technique was confirmed by studying Zn electrodeposition. Our direct observations not only provide new insights into understanding the nucleation and growth but also give guidelines for the design and synthesis of desired nanostructures for specific applications. Finally, the capability of controlling the chemical environment adds another dimension to the existing liquid phase TEM technique, extending the possibilities to study a wide range of dynamic phenomena in liquid media. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbon (PAH) derivatives are mutagenic, carcinogenic, teratogenic and bioaccumulative pollutants. Investigations on hydroxylated PAHs (OH–PAHs) and Nitrated PAHs (NPAHs) in surface water are not enough. In this study, optimization and validation of an analytical method targeting nine kinds of OH–PAHs and one kind of nitrated PAH in environmental water samples are presented. The method was validated for linearity, limits of detection and quantification and recovery using spiked matrix. The linear range of most target compounds was 0.1–200 ng·mL−1 . However, the linear range of 1–hydroxy pyrene and 3–hydroxy benzo[a]pyrene started at 1 ng·mL−1 and the linear range of 1–hydroxy phenanthrene and 9–hydroxy benzo[a]pyrene could not reach 200 ng·mL−1 . All the correlation coefficients (r2 ) were over 0.997. The instrumental limits of detection (LOD) and method detection limits (MDL) ranged from 0.01 to 0.67 ng·mL−1 and 1.11 to 2.26 ng·L −1, respectively. With this method, a lake in Hebei province, China, were screened. Three kinds of target compounds were detected. The average concentration was around 2.5 ng·L −1, while the highest concentration reached 286.54 ng·L −1 . [ABSTRACT FROM AUTHOR]

Perovskite oxides are regarded as promising electrocatalysts for water splitting due to their cost‐effectiveness, high efficiency and durability in the oxygen evolution reaction (OER). Despite these advantages, a fundamental understanding of how critical structural parameters of perovskite electrocatalysts influence their activity and stability is lacking. Here, we investigate the impact of structural defects on OER performance for representative LaNiO3 perovskite electrocatalysts. Hydrogen reduction of 700 °C calcined LaNiO3 induces a high density of surface oxygen vacancies, and confers significantly enhanced OER activity and stability compared to unreduced LaNiO3; the former exhibit a low onset overpotential of 380 mV at 10 mA cm−2 and a small Tafel slope of 70.8 mV dec−1. Oxygen vacancy formation is accompanied by mixed Ni2+/Ni3+ valence states, which quantum‐chemical DFT calculations reveal modify the perovskite electronic structure. Further, it reveals that the formation of oxygen vacancies is thermodynamically more favourable on the surface than in the bulk; it increases the electronic conductivity of reduced LaNiO3 in accordance with the enhanced OER activity that is observed. [ABSTRACT FROM AUTHOR]

Oxide perovskites have emerged as an important class of materials with important applications in many technological areas, particularly thermocatalysis, electrocatalysis, photocatalysis, and energy storage. However, their implementation faces numerous challenges that are familiar to the chemist and materials scientist. The present work surveys the state-of-the-art by integrating these two viewpoints, focusing on the critical role that defect engineering plays in the design, fabrication, modification, and application of these materials. An extensive review of experimental and simulation studies of the synthesis and performance of oxide perovskites and devices containing these materials is coupled with exposition of the fundamental and applied aspects of defect equilibria. The aim of this approach is to elucidate how these issues can be integrated in order to shed light on the interpretation of the data and what trajectories are suggested by them. This critical examination has revealed a number of areas in which the review can provide a greater understanding. These include considerations of (1) the nature and formation of solid solutions, (2) site filling and stoichiometry, (3) the rationale for the design of defective oxide perovskites, and (4) the complex mechanisms of charge compensation and charge transfer. The review concludes with some proposed strategies to address the challenges in the future development of oxide perovskites and their applications. [ABSTRACT FROM AUTHOR]

While direct solar‐driven water splitting has been investigated as an important technology for low‐cost hydrogen production, the systems demonstrated so far either required expensive materials or presented low solar‐to‐hydrogen (STH) conversion efficiencies, both of which increase the levelized cost of hydrogen (LCOH). Here, a low‐cost material system is demonstrated, consisting of perovskite/Si tandem semiconductors and Ni‐based earth‐abundant catalysts for direct solar hydrogen generation. NiMo‐based hydrogen evolution reaction catalyst is reported, which has innovative "flower‐stem" morphology with enhanced reaction sites and presents very low reaction overpotential of 6 mV at 10 mA cm−2. A perovskite solar cell with an unprecedented high open circuit voltage (Voc) of 1.271 V is developed, which is enabled by an optimized perovskite composition and an improved surface passivation. When the NiMo hydrogen evolution catalyst is wire‐connected with an optimally designed NiFe‐based oxygen evolution catalyst and a high‐performance perovskite‐Si tandem cell, the resulting integrated water splitting cell achieves a record 20% STH efficiency. Detailed analysis of the integrated system reveals that STH efficiencies of 25% can be achieved with realistic improvements in the perovskite cell and an LCOH below ≈$3 kg−1 is feasible. [ABSTRACT FROM AUTHOR]

Critical catalysis studies often lack elucidation of the mechanistic role of defect equilibria in solid solubility and charge compensation. This approach is applied to interpret the physicochemical properties and catalytic performance of a free‐standing 2D–3D CeO2−x scaffold, which is comprised of holey 2D nanosheets, and its heterojunctions with MoO3−x and RuO2. The band gap alignment and structural defects are engineered using density functional theory (DFT) simulations and atomic characterization. Further, the heterojunctions are used in hydrogen evolution reaction (HER) and catalytic ozonation applications, and the impacts of the metal oxide heteroatoms are analyzed. A key outcome is that the principal regulator of the ozonation performance is not oxygen vacancies but the concentration of Ce3+ and Ce vacancies. Cation vacancy defects are measured to be as high as 8.1 at% for Ru‐CeO2−x. The homogeneous distribution of chemisorbed, Mo‐oxide, heterojunction nanoparticles on the CeO2−x holey nanosheets facilitates intervalence charge transfer, resulting in the dominant effect and resultant ≈50% decrease in overpotential for HER. The heterojunctions are tested for aqueous‐catalytic ozonation of salicylic acid, revealing excellent catalytic performance from Mo doping despite the adverse impact of Ce vacancies. The present study highlights the use of defect engineering to leverage experimental and DFT results for band alignment. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are considered to be promising candidates for electrochemical water splitting. However, most MOFs are characterized by low electronic conductivity limiting their use as bulk materials for anodes and cathodes. Furthermore, the understanding of the critical parameters controlling the activity and stability of MOF electrocatalysts is still insufficient. Herein, a systematic analysis is presented of the key structural parameters controlling the oxygen evolution reaction (OER) performance and stability of a representative family of bimetallic NiFe‐MOFs, where the role of the metal cations on the accessible active sites and intrinsic activity can be investigated independently from the crystal structure. The models and in‐depth structural and morphological characterizations reveal a hierarchy of properties affecting the OER activity with accessible sites and intrinsic activity playing a major role in the charge transfer efficiency. Optimization of these properties and addition of a conductive support substrate leads to efficient MOF‐nanocomposite electrocatalysts achieving a low overpotential of 258 mV at a current density of 10 mA cm−2 with a small Tafel slope of 49 mV dec−1 and excellent stability for more than 32 h of continuous OER in alkaline medium. [ABSTRACT FROM AUTHOR]

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 Nb2O5 and 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. 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. [ABSTRACT FROM AUTHOR]

This study aimed to determine the photocatalytic activity of photo-Fenton reagent in the photodegradation of 4-Nitrophenol. For this purpose, Fe(III) tetraphenyl porphyrin encapsulated NaY zeolite (FeTPP/NaY) was successfully synthesised via the zeolite synthesis method. The effects of catalyst amount, H2O2 and UV illumination, concentration of 4-Nitrophenol and pH value on the photodegradation process were examined. Ultraviolet–Visible spectroscopy studies revealed that catechol, benzoquinone, and nitrate as the key intermediate species for photodegradation of 4-Nitrophenol. The chemical oxygen demand analysis indicated mineralisation of pollutant which exhibits 85% conversion of 4-Nitrophenol after 120 min irradiation. Rational design of FeTPP/NaY Nanocomposite as Fenton reagent for efficient photodegradation of 4-Nitrophenol was reported, and the possible reaction pathways of the photocatalytic reaction were proposed. [ABSTRACT FROM AUTHOR]

Transition metal oxide nanostructures are drawing much attention as promising electrodes for advanced rechargeable batteries. However, due to the intrinsic low electronic conductivity and substantial volume change during cycling, the electrodes usually show low rate capability and poor cycling life. Herein, we report a route combining surface/interface engineering and defect chemistry to tune the lithium storage properties in nanoscale cubic Co3O4 crystallites. The Co3O4 crystallites were annealed in an inert atmosphere by carefully controlling the temperature, which induces the conformal formation of CoO layers with a tunable thickness on the surface of initial cubes. Microstructural characterizations and electrochemical measurements indicate that the optimized sample possesses a CoO thickness of ∼1.1 nm and shows a reversible lithium storage capacity of 1069.4 mAh·g–1 after 100 cycles of a current density of 0.1 A·g–1. A capacity of 807.9 mAh·g–1 can be obtained at a rate of 5 A·g–1. The improved lithium storage performance is attributed to the unique CoO–Co3O4 interface structure and defect chemistry, which induces a strong electric field at the sharp Co3O4–CoO interface according to density functional theory calculations. The optimized sample also shows it improved sodium storage properties. This work thus provides an effective strategy for the design and synthesis of advanced electrode materials for energy applications. [ABSTRACT FROM AUTHOR]

Mesoporous Y zeolites were prepared by the sequential chemical dealumination (using chelating agents such as ethylenediaminetetraacetic acid, H4EDTA, and citric acid aqueous solutions) and alkaline desilication (using sodium hydroxide, NaOH, aqueous solutions) treatments. Specifically, the ultrasound-assisted alkaline treatment (i.e., ultrasonic treatment) was proposed as the alternative to conventional alkaline treatments which are performed under hydrothermal conditions. In comparison with the hydrothermal alkaline treatment, the ultrasonic treatment showed the comparatively enhanced efficiency (with the reduced treatment time, i.e., 5 min vs. 30 min, all with 0.2 mol·L−1 NaOH at 65°C) in treating the deal-uminated Y zeolites for creating mesoporosity. For example, after the treatment of a dealuminated zeolite Y (using 0.1 mol·L−1 H4EDTA at 100°C for 6 h), the ultrasonic treatment produced the mesoporous zeolite Y with the specific external surface area (Sexternal) of 160 m2·g·−1and mesopore volume (Vmeso) of 0.22 cm3·g−1, being slightly higher than that by the conventional method (i.e., Sextemal= 128 m2·g−1 and Vmeso = 0.19 cm3·g−1). The acidic property and catalytic activity (in catalytic cracking of n-octane) of mesoporous Y zeolites obtained by the two methods were comparable. The ultrasonic desilication treatment was found to be generic, also being effective to treat the dealuminated Y zeolites by citric acid. Additionally, the first step of chemical dealumination treatment was crucial to enable the effective creation of mesopores in the parent Y zeolite (with a silicon-to-aluminium ratio, Si/Al = 2.6) regardless of the subsequent alkaline desilication treatment (i.e., ultrasonic or hydrothermal). Therefore, appropriate selection of the condition of the chemical dealumination treatment based on the property of parent zeolites, such as Si/Al ratio and crystallinity, is important for making mesoporous zeolites effectively. [ABSTRACT FROM AUTHOR]

Precise control over the morphology of nanomaterials is critical yet challenging. The present work reports an efficient approach to tailor the architecture of nanostructures. The process involves rapid disassembly/reassembly of an unstable metal-based coordination polymer (MCP) by controlling the kinetics of the reassembly process. The synthesis procedure delivers unprecedented polycrystalline nanostructures, e.g., holey 2D CeO2−x nanosheets, with precisely tailored thicknesses in the range of 10–100 nm, and hollow 3D pseudo-octahedra and spheres. The consequent high surface areas and pore volumes, short diffusion distances, and high defect densities of the holey 2D CeO2−x indicate significant densities of active sites. This holey architecture exhibits rapid CO conversion and outstanding solar light photocatalytic performance. This approach of directed assembly offers a template-free, controllable, and cost-effective approach to achieve engineered CeO2−x architectures, which are nearly impossible through existing approaches. [ABSTRACT FROM AUTHOR]

A series of unsupported and supported vanadium phosphorus oxide catalysts were prepared by employing a new strategy, which significantly reduced the complexity of catalyst preparation. The greatly simplified catalyst fabrication benefits a greener and lower-cost process for practical applications. The currently fabricated systems showed ca. 90% target product(s) selectivity with a promising yield as well as catalyst durability. [ABSTRACT FROM AUTHOR]

As a metal-free semiconductor, graphitic carbon nitride (g-C3N4) has received extensive attention due to its high stability, nontoxicity, facile and low-cost synthesis, appropriate band gap in the visible spectral range and wide availability of resources. The dimensions of g-C3N4 can influence the regime of the confinement of electrons, and consequently, g-C3N4 with various dimensionalities shows different properties, making them available for many stimulating applications. Although there are some reviews focusing on the synthesis strategy and applications of g-C3N4, there is still a lack of comprehensive review that systemically summarises the synthesis and application of different dimensions of g-C3N4, which can provide an important theoretical and practical basis for the development of g-C3N4 with different dimensionalities and maximises their potential in diverse applications. By reviewing the latest progress of g-C3N4 studies, we aim to summarise the preparation of g-C3N4 with different dimensionalities using various structural engineering strategies, discuss the fundamental bottlenecks of currently existing methods and their solution strategies, and explore their applications in energy and environmental applications. Furthermore, it also puts forward the views on the future research direction of these unique materials. [ABSTRACT FROM AUTHOR]

Due to their high efficiency and stability, triple-cation based perovskite solar cells (PSCs) have now crossed 23% power conversion efficiency (PCE). However, the perovskite composition and type of the electron transport layer (ETL) play a key role in improving their performance. Therefore, in the present investigation, high quality TiO2/SnO2 bilayer ETLs and thermally stable reduced methylammonium (MA) cation based triple-cation perovskite layers are used to fabricate thermally stable PSCs. By retaining their normal (n–i–p) device architecture, the influence of antisolvents on the perovskite layer has been investigated in detail. Systematic studies in this work reveal that the amorphous SnO2/TiO2 bilayer and the trifluorotoluene (TFT) processed perovskite layer significantly influence the current density and open circuit voltage (VOC) and reduce the charge recombination of perovskite devices. The optimised devices having micrometer size grains exhibited ＞20.5 ± 0.5% PCE for a thermally stable Rb0.05(FAPbI3)0.95(MAPbBr3)0.05 perovskite composition with a SnO2/TiO2 bilayer ETL. Furthermore, the SnO2:TiO2 bilayer ETL-containing PSCs are thermally stable for more than 200 hours at 80 °C. [ABSTRACT FROM AUTHOR]

Despite the fact that its crystal state is thermodynamically stable, Cu64Zr36 alloy is prone to form metastable glass at a high cooling rate. However, the confinement can induce nano-crystallization with a novel sandwich-like hierarchical structure consisting of pure Cu layers, pure Zr layers and mixed layers by conducting molecular dynamics simulations. The liquid-to-crystal transition temperature and interatomic repulsion softness display abnormal oscillations, instead of monotonous variation, as the wall–wall separation increases. When the confinement size is 10 Å and 12 Å, the transition temperature reaches a maximum, resulting from the pending new sandwich layer. The atomic movement and dynamical heterogeneity are demonstrated to play a vital role in the abnormal oscillation behavior of physical properties of the nano confined metallic glass. The sandwich-like structure can alter the Cu–Zr bond fraction, which eventually influences the liquid-to-crystal transition temperature and interatomic repulsion softness. Our findings provide a deep insight into the hierarchical nanostructures and its liquid-to-crystal transition characteristics under confinement at the atomic level. [ABSTRACT FROM AUTHOR]

Three structurally distinct interfaces, i. e. Au/α-Fe2O3-THB-Air, Au/α-Fe2O3-HS-Air, and Au/α-Fe2O3-QC-Air, with the major substrate facet being {113}, {001}, and {012} respectively, were controllably prepared. The low temperature water gas shift (WGS) reaction (100-260 °C) was applied to these unique systems to reveal how these structurally distinct interfaces can impact on the reaction behavior. With the detailed performance evaluation plus the characterizations of CO-TPSR, XPS, and in situ-FTIR in particular, the correlations between the evolution of different intermediates and the distinct catalytic behaviors have been established. The substrate facet structure and the Au entity largely determine the form and reactivity of surface OH/ H2O species which in turn determine the formation of different intermediates and eventually the product formation. The Au/α-Fe2O3-THB-Air is enriched with oxygen vacant sites, favorable for dissociative adsorption of H2O, carboxyl intermediate formation and H2 production. The Au/α-Fe2O3-HS-Air is enriched with surface lattice oxygen, favorable for molecular adsorption of H2O, formate intermediate formation, and CO2 production. The Au/α-Fe2O3-QC-Air interface is enriched with surface Fe sites, favorable for dissociative adsorption of H2O and evolution of stable carboxyl intermediate as well as isolated OH species at low reaction temperatures. The findings are informative to control the interfacial structure for the WGS and other reactions. [ABSTRACT FROM AUTHOR]

The interactions between the reactants and catalysts surfaces play a significant role in heterogeneous catalysis, thus to tune the interfacial properties between them has emerged as an important topic. This review has summarised some recent advances about the effects of wettability on the catalytic reactions, including hydrophilicity, hydrophobicity, and dewetting properties. In addition, the effect of coalescence dynamics among the catalyst particles is also discussed based on a series of investigations. Although the researchers have realised the importance of wettability, the ability to tune the wettability in their work needs to be further enhanced. Therefore, we finally highlighted considerable useful approaches to achieve controllable wettability and coalescence. It is expected that in the future design of catalysts, researchers should pay more attention to tuning the interfacial structure to achieve the enhanced catalysts behaviours. Wet wet wet: Surface wettability and coalescence dynamics have a great impact on the catalyst activity and the preparation of catalyst, and the catalytic performances could be significantly improved by the fine control of surface wettability and coalescence dynamics. Here, the authors provide many effective approaches to achieve the controllable surface wettability and coalescence, which is expected to be applied in the catalytic field. [ABSTRACT FROM AUTHOR]

A simple, practical and precise method for the simultaneous analysis of 32 different polycyclic aromatic hydrocarbon (PAHs) including 16 parent PAHs, 8 oxygenated-PAHs (oxy-PAHs), 4 chloro-PAHs, and 4 nitrogen-containing heterocyclic PACs (N-PACs), in groundwater was established via gas chromatography-mass spectrometry (GC-MS) combined with liquid-liquid extraction (LLE). The obtained detection method possesses instrument detection limits (at a signal to noise of 3:1) in the range of 0.05-10 ng/mL and method detection limits in the range of 1.7-13.2 ng/L. The average recoveries of the 32 analytes were in the range of 54.3%-127.0% with relative standard deviations (RSDs) < 20%, and the recoveries of 16 PAH derivatives ranged from 54.3 to 115.1% with RSDs < 17.9%. The method has been successfully applied to the screening of 64 groundwater samples from eastern China. The results revealed that 30 types of targets including 16 PAHs and 14 PAH derivatives were detected and that the groundwater in most areas is slightly polluted, while the pollution of Jiangsu Province and Shandong Province was more serious. [ABSTRACT FROM AUTHOR]

A Ni loaded catalyst on mesoporous ceria, with a large surface area, prepared through the surfactant-assisted precipitation and impregnation method was investigated as an efficient catalyst for propane partial oxidation to produce synthesis gas. The results show that 2.5 wt% Ni/CeO2 had the optimum Ni loading, exhibiting the highest catalytic propane conversion. It also showed excellent stability, with no obvious activity drop after a 10 h time-on-stream reaction and slightly decreased in H2 and CO yields. The investigation of the reactant composition effect on carbon formation showed that by decreasing the C/O2 ratio the content of accumulated carbon decreased and propane conversion increased. The good activity of the Ni/CeO2 can be ascribed to the high surface area and rich surface defects of the ceria support and a high dispersion of active sites (Ni nanoparticles). [ABSTRACT FROM AUTHOR]

Abstract: The rational design of low‐cost transition metal catalysts that exhibit high activity and selectivity may be the most significantly investigated in heterogeneous catalysis. In this study, Co3‐xMnxO4 (x=0.75, 1.0, and 1.5) mixed metal oxides were successfully synthesized by a controlled template‐free autoclave strategy and studied for toluene oxidation. It is found that the Co‐rich sample showed markedly enhanced activity and the 3D dandelion‐like Co2.25Mn0.75O4 catalyst exhibited in the highest toluene oxidation rate (8.9 μmol/(gcats)) and a 100 % toluene conversion at 239 °C. In situ DRIFTS study indicates that toluene was sequentially oxidized to benzyl radical, benzaldehyde, benzene, oxalic acid, and finally to CO2 and H2O. The interaction between Co and Mn, in conjunction with the high concentration of surface oxygen species and rich surface oxygen vacancies, reasonably explains the elevated catalytic activity and thermal stability for toluene oxidation over 3D flower‐like Co3‐xMnxO4 spinel catalysts. [ABSTRACT FROM AUTHOR]

Using [Ni{(POEt)3}4] as catalyst precursor for the catalytic isomerization of allylbenzene to beta‐methylstyrene, time‐course studies suggest a mechanism that is consistent with an autocatalytic reaction. The sigmoidal curve observed when plotting conversion vs. time fits exceptionally well to a kinetic model of an autocatalytic process (R2 = 0.998). We show that the uncoordinated phosphite, generated during the catalyst activation, reduces the acid concentration and, consequently, has a detrimental effect on the formation of the protonated active nickel catalyst. The nickel complex protonation is seen as a key step in forming the active catalytic species. The novel use of a mercury salt as a phosphite scavenger leads to inhibition of the free phosphite's capability to lower acid concentration, improving the catalytic performance of the system, consistent with the mechanism proposed. [ABSTRACT FROM AUTHOR]

This feature article summarizes the recent progress in porous perovskite oxides as advanced catalysts for both energy conversion applications and various heterogeneous reactions. Recently, research has been focused on specifically designing porous perovskite materials so that large surface areas can be harnessed and surface properties can be improved. Numerous potential applications of porous perovskites have been investigated, including heterogeneous catalysis and air battery applications that rely on interactions and/or reactions of other components with porous perovskites. The main objective of this article is to examine the progress of recent research studies on porous perovskite nanomaterials, including the preparation methods and their applications in catalysis and batteries. The wide variety of the related knowledge on porous mixed oxides can provide guidance for researchers with interests ranging from the design of functionalized materials to the field of heterogeneous catalysis and electrochemical applications. [ABSTRACT FROM AUTHOR]

Abstract: 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.Graphical abstract: [ABSTRACT FROM AUTHOR]

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-Al2O3 catalyst, 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. [ABSTRACT FROM AUTHOR]

Ordered meso/macroporous metal oxides have gained increasing attention in heterogeneous catalysis arising from their large surface areas and pore volumes, elevated catalytic activity and good thermal stability. Compared to nonporous metal oxides, their most prominent feature is the ability to interact with molecules not only at their exterior surface but also within the large interior surface of the material. The past decade has witnessed substantial advances in the synthesis of new porous metal oxides with ordered structures for use in a wide range of applications. By recalling some of the classical fundamentals of porous materials, this review examines the recent developments in ordered meso- and macro-porous metal oxide catalysts for heterogeneous catalysis. Additionally, we outline the current challenges in the field of nanoparticle-based catalysis, including the role played by the morphology (size, shape, and porosity) of ordered meso/macroporous metal oxides, and provide a perspective on the need for further advances in porous materials so that their contribution to heterogeneous catalysis can continue to expand. [ABSTRACT FROM AUTHOR]

Highly dispersed Ni nanoparticles supported on high-surface-area mesoporous nanocrystalline MgAl2O4 powder was generated by a facile and simple propylene oxide assisted gelation agent route. The mesoporous spinel materials exhibited enhanced catalytic performance for hydrogen production in biogas dry reforming. The obtained spinel catalysts with different Ni loadings after calcination at 700 °C possessed high BET surface areas (236-224 m2 g−1). A narrow pore size distribution in the mesopore range was observed in the samples, and all the samples except 2.5 wt % Ni showed a mesoporous-macroporous structure. The 5 wt % Ni/MgAl2O4 sample showed the highest activity for the biogas dry reforming reaction because of the high dispersion of Ni on the mesoporous surface of the spinel support. X-ray photoelectron spectroscopy revealed that the catalysts with a low Ni loading undergo the exchange of Mg2+ by Ni2+, whereas catalysts with a higher Ni loading undergo the substitution of Al3+ by Ni3+. Thus, appropriate partial Ni substitution in the MgAl2O4 support may play a role in the elevated catalytic performance. [ABSTRACT FROM AUTHOR]