Metal Nanocatalysts For Highly Efficient Hydrogen Evolution From Hydrolysis Of Hydrazine And Ammonia Borane

With the rigorous situation of the energy crisis and environmental deterioration,many people pay more attention to the need for hydrogen.Hydrogen,as a promising energy carrier available to satisfy the increasing demand for a renewable and clean energy supply,has become a hot research topic.Now,there are many ways to produce hydrogen,such as water splitting by electrocatalysis and photocatalysis,hydrogen adsorption materials,fossil fuels reforming,chemical hydrogen storage material and so on.This paper used chemical storage materials as starting point study metal nanocatalysts for highly efficient hydrogen evolution from hydrolysis of hydrazine and ammonia borane.Among them,hydrous hydrazine(H2NNH2 H2O)has the advantages of high hydrogen content(8.0 wt%),easy recharging,and the production of 2 mol hydrogen through the reaction(H2NNH2?N2(g)+2H2(g)),which makes it one of the most compelling candidates for practical application.NH3 could be released through the reaction(3H2NNH2?N2(g)+4NH3(g)),which should be avoided.Ammonia borane(NH3BH3)with high hydrogen content(19.6 wt.%),good stability in aqueous solution,making it an attractive and promising candidate for the chemical hydrogen storage.NH3BH3 can release 3 mol hydrogen gas through catalytic hydrolysis under an ambient atmosphere(NH3BH3+2H2O?NH4BO2(1)+3H2(g)).So,design and synthesis efficient metal nanocatalyst for dehydrogenation from hydrous hydrazine and ammonia borane at mild condition is the key to hydrogen development.This paper is aimed to study metal nanoparticles as highly efficient catalysts for hydrogen evolution from hydrolysis of hydrazine and ammonia borane.This paper includes three parts.(1)The first part is NiPt nanocatalysts supported on boron and nitrogen codoped graphene(BNG)for superior hydrazine dehydrogenation.BNG synthesized by a two-step method,with the highest C-B and C-N contents,and the lowest covalent B-N ratios,supported NiPt nanoparticles exhibit superior catalytic activity toward hydrazine dehydrogenation(TOF= 199.4 h-1)at room temperture.(2)The second part report a simple oneport strategy to prepare reduced graphene oxide(rGO)supported rhodium phosphide nanoparticles(RhP/rGO)with different P content.The contents of phosphorus were controlled by turning the initial quality of NaH2PO2.Thanks to the electronic effect of P doping,the resultant RhP/rGO catalysts exhibit extremely high catalytic activity and durability toward dehydrogenation of hydrazine,which emphasized the role of P doping.(3)The third part is report an in-situ reduction synthesis of reduced graphene oxide(rGO)supported amor:phous NiP nanoparticles(NiP/rGO),and their superior catalytic activity toward hydrolytic dehydrogenation of ammonia borane.Unexpectedly,the resulted NiP/rGO catalyst exhibits a high catalytic activity with initial TOF value of 13.3 min-1 and high stability toward hydrogen generation from NH3BH3.Moreover,the activation energy(Ea)is measured to be 34.7 kJ·mol-1,further indicating that it's highly catalytic activity and better kinetic performance.