Layered double hydroxides (LDHs) exhibit excellent performance of electrocatalytic hydrogen and oxygen evolution due to their variable ions within layers,exchangeability of anions between layers,and large reaction surfaces.In addition,LDHs?based derivatives can equip catalysts with multiple functions and better performance,which show significant advantages and excellent application prospects in many fields.In this paper,the properties of LDHs?based lamellar structure,such as tunable property,ability to be delaminated and assembled,and structural memory effect,as well as common preparation methods involved in LDHs?based high?efficiency electrocatalysts,such as the delamination method,co?precipitation method,and hydrothermal method have been stematically analyzed.In addition,the applications of LDHs and their compound derivatives were systematically reviewed in electrocatalytic fields,including the oxygen evolution reaction and hydrogen evolution reaction by water electrolysis, the electrocatalytic oxidation reaction of ethanol,and the oxygen reduction reaction.Finally,the problems and solutions involved in LDHs materials were analyzed and predicted.

The activation of peroxymonosulfate (PMS) by cobalt?based catalysts has the advantages of high catalytic activity, simple operation, easy recyclability, and low cost. Hence, it has attracted much attention in the field of advanced oxidation processes in recent years. This paper reviewed typical methods for the synthesis of cobalt?based catalysts, including solid phase, gas phase, and liquid phase methods. Several types of cobalt?based catalysts for PMS activation, including cobalt oxides with special morphologies, supported cobalt catalysts, and cobalt?based composite metal oxides, were summarized. The applications of these cobalt?based catalysts in environmental remediation via PMS activation were also elaborated, such as the degradation of organic dyes, endocrine?disrupting chemicals, and pharmaceutical and personal care products. Finally, the current shortcomings of cobalt?based catalysts in PMS activation were summarized, and some future research directions in this area were proposed.

The concentration of CO₂ in the atmosphere reached an all?time high in the 2021(414.7 μg/g), which has caused a series of ecological and environmental problems. In order to solve the problem of global warming, CO₂ resource utilization is imperative. From the view of CO₂ utilization and methanol (MeOH) economy, the preparation of MeOH by CO₂ hydrogenation is a potential energy route, which can be used as one of the key paths to achieve carbon neutrality. The recent progress in preparation of MeOH by reduction of CO₂ with H₂ as reductant in homogeneous system was summarized.According to the three routes of preparing MeOH by direct hydrogenation of CO₂,preparing MeOH by hydrogenation of CO₂ derivatives,and preparing MeOH by dissimilation of HCOOH,the catalyst system design,structure?activity relationship and reaction mechanism involved in each route were introduced,and the shortcomings of each hydrogenation route were summarized,the problems needed to be solved in the industrial production of MeOH by CO₂ hydrogenation were put forward.

A series of Y zeolite?encapsulated Ru metal catalysts were prepared by the in?situ hydrothermal method, ion exchange method,and impregnation method.The effects of the Ru metal introduction sequence during the in?situ hydrothermal synthesis process and the synthesis methods on the physical properties and catalytic performance were discussed.Methods including XRD, XRF,and SEM were used to characterize the composition and structure of samples, and the presence states of Ru metal in zeolite were characterized by H₂?TPR,H₂?TPD,TEM,CO?IR,and XPS.The acidity properties of the samples were characterized by NH₃?TPD and Py?IR.The results indicate that the addition order of Ru metal has little effect on the zeolite synthesized by the in?situ hydrothermal method,and this method is the best choice for Ru metal encapsulation.For the isomerization of isobutane to n?butane, the prepared Ru@HY?Si exhibits the highest isobutane conversion and n?butane selectivity and optimal catalytic activity at 673 K with a mass space velocity of 4 h^-1.

Two?dimensional transition metal carbides and nitrides (MXenes) have become a high?profile material with a wide range of application prospects due to their efficient adsorption and catalytic properties,wide optical absorption range,and excellent conductivity.Ni?doped Nb₂C material has positive photocatalytic properties.To explore the intrinsic mechanism of photocatalytic property improvement by Ni?doped Nb₂C,the electronic structure properties of Nb₂C and its Ni?functionalized form(i.e.,Ni?Nb₂C) and their adsorption properties for CO₂ gas molecule by using the density functional theory (DFT) were investigated.The results show that the replacement of an Nb atom by a Ni atom makes the charge density around the Ni atom increase and further results in a redistribution of the charge density of the substrate,which leads to an improved electronic environment for catalyzing CO₂ and improves the photocatalytic property for CO₂.

Catalytic pyrolysis is an effective way to use lignin resource.A ternary metal?organic framework (MOF) precursor was synthesized by using the solvothermal method, and then the perovskite Ca_1-x Nd _x CoO₃ (CNC?x) was prepared by controllable calcination.The performance of the perovskite for catalyzing bagasse lignin (BL) pyrolysis and regeneration was investigated,and the distribution law of the compositions of gaseous and liquid phase products was analyzed. The results show that CNC?0.3 calcined at 800 ℃ shows excellent performance in catalyzing BL pyrolysis.Under a temperature of 200~500 ℃,the pyrolysis activation energy is reduced from 64.24 kJ/mol to 58.92 kJ/mol.Compared with BL pyrolysis,the yield of gaseous phase products decreases,while that of solid phase products increases.The yield of liquid phase products is increased from 15.11% to 17.94%,and the liquid phase products are mainly aromatic oxygenated chemicals including phenols,guaiacols,syringols,and phenyl ethers.The total selectivity of aromatic oxygenated chemicals is 11.0% higher than that under pyrolysis.After five times of regeneration,CNC?0.3 still shows satisfactory structural and catalytic stability.

The NiCo₂O₄ nanorods were prepared by a hydrothermal method with nickel nitrate hexahydrate （Ni(NO₃)₂·6H₂O） as the nickel source,cobalt nitrate hexahydrate （Co(NO₃)₂·6H₂O） as the cobalt source,and urea as the precipitant.Then the above NiCo₂O₄ nanorods were immersed into the RuCl₃ solution to obtain the NiCo₂O₄/Ru composite catalyst by reduction.Testing technologies such as X?ray diffraction (XRD) and scanning electron microscopy (SEM) were adopted to characterize the phase structure and morphology of this composite catalyst, and its catalytic performance toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) was investigated by electrochemical methods such as linear scan voltammogram (LSV) and electrochemical impedance spectroscopy (EIS). Moreover, the NiCo₂O₄/Ru composite catalyst was used as the anode to assemble the Zn?air battery, whose open circuit voltage,charge and discharge performance,and cycle stability were evaluated by a LANHE test system. The results show that the NiCo₂O₄/Ru composite catalyst has high ORR/OER bifunctional catalytic activity with an OER overpotential of 420 mV at 10.0 mA/cm² and an ORR half?wave potential of 0.77 V.The assembled Zn?air battery also exhibits an open circuit voltage of 1.37 V, a maximum power density of 143 mW/cm²,as well as robust cycle stability for 50 hours.

NiMo/γ?Al₂O₃ catalyst was prepared by using γ?Al₂O₃ as the carrier and Ni as the active component,and Mo was introduced to improve the metal dispersion of Ni?based catalysts.The physical properties of the catalysts were characterized by means of BET,XRD,H₂?TPD,H₂?TPR,and transmission electron microscopy.The performance of the catalysts was evaluated by hydrogenation units,and the effect of metal dispersion of the catalysts on the catalytic activity was investigated.The results show that the introduction of Mo can effectively weaken the interaction between Ni and the carrier.The low?temperature reduction peak of the H₂?TPR profile significantly moves forward,and the peak intensity is enhanced.The specific surface area of the catalyst activity increases from 0.7 m²/g to 15.3~16.1 m²/g,and the metal dispersion increases from 0.80% to 18.59%,which indicates that the number of metal active centers on catalyst surfaces increases,and the metal dispersion on the catalyst surfaces improves. Under the same process condition,heavy petrol with catalytic cracking is processed,and the desulfurization rate of NiMo?based catalysts is increased by 15.7% compared with that of Ni?based catalysts.The saturation rate of olefin is increased by 4.9%,and the desulfurization selectivity is decreased by 3.4%.Therefore,the NiMo?based catalysts have positive desulfurization selectivity while ensuring a high desulfurization rate.

As palladium(Pd) catalysts have poor selectivity to the target product in the selective hydrogenation process,a series of PdM/C bimetallic alloy catalysts were synthesized by the simple co?reduction of second metals (M=Mn,Fe,Co,Ni) and Pd. With 3?nitrostyrene as the model molecule and H₂ as the hydrogen source, this study investigated the effect of second metals on the selective hydrogenation performance of Pd?based catalysts. The Pd?based catalysts were characterized and tested by methods including X?ray diffraction (XRD), transmission electron microscope (TEM),and gas chromatography.The results reveal that when pure Pd/C is used as the catalyst, the conversion reaches 100% for 1.5 h, but the selectivity of 3?nitrophenylethane is only 29%, and the selectivity of 3?aminophenylethane is 71%. After the introduction of second metals, the selectivity of 3?nitrophenylethane is increased to 75%~100% under the same conditions. Among them,PdFe/C has the best performance(100%) in the hydrogenation of 3?nitrostyrene to 3?nitrophenylethane, and high conversion(100%) and selectivity (99%) of 3?nitrophenylethane can still maintain after ten reaction cycles. It can effectively avoid over?hydrogenation and realize the selective hydrogenation of 3?nitrostyrene to 3?nitrophenylethane.