Highly enhanced catalytic stability of copper by the synergistic effect of porous hierarchy and alloying for selective hydrogenation reaction

Supported copper has a great potential for replacing the commercial palladium-based catalysts in the field of selective alkynes/alkadienes hydrogenation due to its excellent alkene selectivity and relatively high activity. However, fatally, it has a low catalytic stability owing to the rapid oligomerization of alkenes on the copper surface. In this study, 2.5 wt% Cu catalysts with various Cu:Zn ratios and supported on hierarchically porous alumina (HA) were designed and synthesized by deposition–precipitation with urea. Macropores (with diameters of 1 μm) and mesopores (with diameters of 3.5 nm) were introduced by the hydrolysis of metal alkoxides. After in situ activation at 350 °C, the catalytic stability of Cu was highly enhanced, with a limited effect on the catalytic activity and alkene selectivity. The time needed for losing 10% butadiene conversion for Cu1Zn3/HA was ~40 h, which is 20 times higher than that found for Cu/HA (~2 h), and 160 times higher than that found for Cu/bulky alumina (0.25 h). It was found that this type of enhancement in catalytic stability was mainly due to the rapid mass transportation in hierarchically porous structure (i.e., four times higher than that in bulky commercial alumina) and the well-dispersed copper active site modified by Zn, with identification by STEM–HAADF coupled with EDX. This study offers a universal way to optimize the catalytic stability of selective hydrogenation reactions

Methyl Halide to Olefins and Gasoline over Zeolites and SAPO Catalysts:A New Route of MTO and MTG

Rational and efficient conversion of methane to more useful higher hydrocarbons is one of the most important topics of natural gas utilization.Although methane activation and its conversion to valuable compounds attract an increasing attention,methane conversion is often made in indirect way through the very energy-consuming step for syngas production from steam reforming of methane.Some promising results appeared to be of significance for the development of an alternative and potential route for the production of high value-added products from methane.Efficient conversion of methane to higher hydrocarbons could be realized via methyl halide as the intermediate.After the production of halomethane,they could be transformed to gasoline and light olefins over modified zeolites and SAPO molecular sieves.High conversion efficiency and selectivity indicated the feasibility of industrial application.The research gained recently growing interest from the point of view in both fundamental research and industrial application.The study on the reaction mechanism shed light on the possible route of C-C bond construction from methyl halide,which is the very important issue of the C1-reactant conversion to higher hydrocarbons.Hydrogen halide generation during methyl halide conversion did not exert apparent impact on the reaction mechanism and the structure stability of the catalysts.This review deals with the evolution of the field and comments the advantages to be explored and the drawbacks to be prevented for the development of new and sustainable methane-to-olefins（MTO） and methane-to-gasoline（MTG） routes via methyl halides

A PtPdCu thin-film catalyst based on titanium nitride nanorod arrays with high catalytic performance for methanol electro-oxidation

Novel thin-film PtPdCu ternary electrocatalysts supported on titanium nitride nanorod arrays (TiN NRs) are fabricated. Unique 3D structures provide an effective way to analyse the influence of catalytic structure on methanol electrooxidation. The PtPdCu-TiN NRs show 1.81-and 2.09-fold greater mass activity than that of PtPd-TiN NRs, and a commercial PtC catalyst, respectively