The Synthesis Of Multi-component Composite Nano-catalyst And The Study Of Its Catalytic Performance In Hydrogen Desorption Of Borane Ammonia

As one of the best alternative energy sources,hydrogen has the potential to meet the growing demand for efficient and clean energy supplies.Currently,finding an efficient hydrogen production and storage systems is one of the most difficult challenges to achieving a secure future hydrogen energy society.In recent years,ammonia borane?AB?complex has become one of the important hydrogen storage materials due to its high hydrogen content?19.6 wt%?,good stability and non-toxicity.Platinum?Pt?is the best catalyst for the hydrolysis of borane ammonia,however,Pt is expensive and its natural content is very low.In order to reduce the cost of catalysts and maintain high catalytic performance,this paper tries three solutions,the main contents are as follows:1.The catalytic hydrolysis of borane ammonia to release hydrogen at room temperature was studied by using Co₃O₄@GO as the non-precious metal support to load ultra-small Pt nanocluster.In this chapter,ethanol solution of graphene oxide?GO?and aqueous solution of cobalt acetate were used as the precursors to obtain the support material of Co₃O₄@GO through reflux and hydrothermal reaction,and then Pt@Co₃O₄@GO was obtained by low-temperature treatment the mix welled support material and H₂Pt O₆under the reduction gas of H₂.The catalytic hydrolysis of borane ammonia showed that the catalyst had excellent catalytic performance,with a TOF value of 2766 mol _H2mol _Pt^-1min^-1at room temperature and an activation energy of24.3 k J·mol^-1.This excellent catalytic activity may be attributed to the synergistic effect of ultra-small Pt nanocluster,Co₃O₄accelerating the adsorption of hydroxyl species and the support of GO facilitate the electron/mass transfer between reactants/products and enlarge more catalytically active sites,which promoted the breaking of O-H bonds in the attacking H₂O molecules in the rate-determining step of AB hydrolysis.2.A composite catalyst including copper?Cu?,composite metal oxide?Cu Co O_x?and graphene oxide?GO?was designed and synthesized.In this chapter,we first use reflux and hydrothermal reaction of GO with a mixture of copper acetate and cobalt acetate to obtain the GO-loaded composite metal oxide Cu Co O_x,and then further hydrogen low-temperature reduction treatment to obtain the heterostructure of Cu@Cu Co O_x@GO.By adjusting different reduction temperatures,different metal ratios and different catalyst loads,it was found that the catalyst at the optimized interface was Cu_0.3@Cu_0.7Co O_x@GO when the metal load was 13 wt%.It's TOF value was 44.6 mol _H2mol _M^-1min^-1at room temperature,and it's activation energy was35.4 k J·mol^-1.The kinetic isotope effects using D₂O showed that the synergistic advantage of components and structures in Cu_0.3@Cu_0.7Co O_x@GO accelerated the breaking of the O-H bond in H₂O during the rate-determining step.3.The composite catalyst of Cu-Ni composite oxide?Cu Ni₂O_x?supported GO was designed and synthesized,and its catalytic performance of hydrolysis borane ammonia to release hydrogen at room temperature was studied.This chapter use reflux reaction of GO with a mixture of copper acetate and cobalt acetate.After centrifugation and drying,the Cu Ni₂O_x@GO was obtained by annealed in the air.The catalyst has excellent catalytic performance for AB hydrolysis at room temperature,with a TOF of 55.6 mol _H2mol _M^-1min^-1at room temperature.Its catalytic activity may be attributed to the synergistic effect between smaller composite metal oxide particles and GO.