Controllable Construction Of MOFs-Derived Catalysts And Their Catalytic Characteristics On Hydrolysis Of Sodium Borohydride For Hydrogen Production

Hydrogen can effectively solve the serious environmental pollution caused by excessive consumption of fossil fuels.It is of great significance to develop high-performance hydrogen storage/generation materials for the wide application of hydrogen fuel cells and the realization of carbon neutrality,peak carbon dioxide emissions.Hydrogen generation by hydrolysis of sodium borohydride（Na BH₄）has the advantages of high hydrogen storage density,easy control of reaction,high hydrogen purity and environmental friendliness,and it is one of the on-site hydrogen supply materials with promising application prospects.In this paper,the catalytic materials of MOFs derivatives with high specific surface area and diverse structures are designed and successfully prepared around the problem of poor hydrolysis kinetics of Na BH₄,and the effects of different synthesis methods,element composition,morphology and structure on the hydrogen liberation performance of Na BH₄are systematically studied.The specific research contents are as follows:（1）A Co B-LDH-CNT nanosheet composite is synthesized.The composite material is composed of multi-walled carbon nanotubes（MWCNTs）connected with each other,and the surface of the composite material is modified by Co B,with the cake-like structure of Co/Ni-MOF as the precursor.MWCNTs can reconnect layered double hydroxide（LDH）nanosheets during hydrolysis reaction,thus effectively improving the stability and dispersibility of the catalyst.The HGR of Na BH₄ hydrolysis is 5167.7 m L·min^-1·g^-1 at 303 K.After 10 cycles,it still maintains 75.4%of the initial performance.（2）Nano-cluster catalysts containing metal phosphides of Co and Ru is designed reasonably by the method assisted by ZIF-67 template.The excellent overall performance is attributed to its unique composition and structure.The special porous hollow dodecahedron structure exposes more active sites,which provides a diffusion channel for the transmission of hydrogen.The synergistic effect of Ru P₂ and CoP particles significantly increases the hydrolysis hydrogen generation activity.At room temperature,the hydrolysis rate of alkaline Na BH₄ by Ru P₂-CoP is 6681.1 m L·min^-1·g^-1,showing a competitive advantage in metal-supported catalysts.（3）Co/Ru-NSC hydrolysis catalyst is prepared by simple solvent method and chemical reduction with Co-ZIFs-TU/DMSO as precursor.The special hexapod-shaped structure can not only prevent the aggregation of active particles,but also ensure that more active sites are exposed;and it endows the catalyst with a larger surface area,thereby optimizing the material transmission channel.After surface modification of Ru particles,the catalytic hydrolysis performance is significantly improved,and the HGR reach 8459.7 m L·min^-1·g^-1.In addition,the reuse performance is also improved,and the initial performance is 76.8%after being reused for 15 times.Thanks to the synergistic effect of Co and Ru particles,the fold hexapod structure is well maintained.