Steam Reforming Of Methanol For Hydrogen Production Over Clay-Based Zeolite-Supported Cu-Zr Catalyst

As the basic of future energy development,hydrogen energy is not only an important energy power carrier,but also an indispensable raw material of the chemical industry.However,hydrogen storage performance and transportation efficiency are the bottleneck of hydrogen energy network construction.In situ hydrogen production by methanol steam reforming（MSR）can avoid the problems of hydrogen storage and transportation.To solve the key scientific problems of insufficient dispersion of catalyst active components,active metal migration,agglomeration,sintering and low hydrogen yield caused by by-products of various gas in MSR reaction,the porous attapulgite-based zeolite（AZ）was synthesized from economic attapulgite,and a MSR catalyst with high activity,high selectivity and high stability for hydrogen production was explored by loading copper-zirconium active metal in this paper.The mechanism of catalytic conversion reaction was revealed by a variety of characterization techniques.The main research and conclusions are as follows:（1）The hydrothermal acid-treated natural attapulgite was mixed with template agent to synthesis the porous attapulgite-based zeolite materials.After hydrothermal acidification treatment of attapulgite,the aluminum-oxygen octahedron skeleton structure was destroyed,which reduced the content of impurity elements in attapulgite,and the Si O₂ content representing the tetrahedral layer of silicon-oxygen increased from 60.21%to 97.27%.The synthesized AZ exhibited MFI zeolite topological structure,presenting a regular block structure of 2μm size.In addition,there were uniform micropore channels and irregular surface mesoporous structures in AZ.（2）Cu-based catalysts with different supports and metal loads were prepared by wet impregnation with 10wt%Cu,meanwhile,Cu/AZ catalysts with different metal loading were prepared to study the influence of Cu-based catalyst support and loading on MSR reaction activity.The effects of Cu-based catalyst support and loads on MSR reaction activity were studied.It shows that the zeolite supported catalysts Cu/AZ and Cu/S-1 have lower reduction temperatures and higher specific surface area,which is conductive to promoting the dispersion of active metals and the conversion of reactants.Cu/AZ showed the best catalytic activity.The CO selectivity increased with the increase of metal loading of Cu/AZ catalyst.（3）The copper-zirconium composite catalysts with different metal ratios were prepared by co-impregnation method using AZ as support.The effects of zirconium introduction on the physicochemical properties and catalytic performance of copper-based catalysts were studied,and the reaction mechanism of the catalysts was also revealed.It showed that the introduction of Zr significantly increased the dispersion and surface area of active metals and promoted the formation of Cu⁰/Cu⁺-Zr O_xH_y interface site.1Cu1Zr/AZ catalyst showed the best catalytic properties,and the hydrogen yield reached 655.1 mmol/g_cat/h.On the 1Cu1Zr/AZ catalyst,the Cu⁰/Cu⁺species promoted the decomposition of methanol and intermediates,while the zirconium hydroxyl species on the Cu⁰/Cu⁺-Zr O_xH_y interface activated water vapor,providing OH groups to promote the conversion of carbon containing intermediates and C*species.（4）In order to further improve the catalytic performance of Cu-Zr composite catalyst,1wt%Ce,Co,Fe,Zn and Ni were introduced into 1Cu1Zr/AZ catalyst,respectively.It suggested that the introduction of modified metal changes the reducibility of the Cu-Zr catalyst.1Zn Cu Zr/AZ catalyst shows the highest hydrogen yield(895.7 mmol/g_cat/h),and CO selectivity was only 2%.More alkaline sites and many lattice oxygen species in the catalyst could promote the adsorption and desorption of CO₂,the conversion and decomposition of reactants and intermediates,thus improved the catalytic properties of the catalyst.Figure 38 table 11 reference 116...