Synthesis And Study Of Catalytic Properties Of Pt-Ni Bimetallic Catalyst For Hydrogen Generation From Hydrous Hydrazine Decomposition

Hydrogen is a clean,efficient energy carrier,which is expected to play an important role in the future energy field.Safe and efficient approaches of hydrogen storage and delivery remain a central challenge for the widespread penetration of hydrogen energy technologies,For decades,scholars have carried out lots of research on various types of hydrogen storage materials,but no reversible hydrogen storage materials that can be rapidly charged/discharged with high capacity at mild temperature have been found.In recent years,chemical hydrogen storage technology combining controlled hydrogen desorption and hydride regeneration has provided an opportunity to break through the"bottleneck"of hydrogen storage.Among a variety of alternative chemical hydrogen storage materials,Hydrazine hydrate has the advantages of high hydrogen storage density,relatively stable,which has the potential for mobile hydrogen source applications.The development of a catalyst with high catalytic activity,high selectivity for hydrogen production and good durability is the core subject of the development of hydrazine hydrate controllable hydrogen technology.In recent years,through the efforts of scholars at home and abroad.Positive progress has been made in the research of catalysts for the decomposition of hydrazine hydrate to produce hydrogen.Through the use of modification strategies such as alloying and alkaline supports,a series of catalysts that can catalyze the complete decomposition of hydrazine hydrate to produce hydrogen under mild temperature conditions have been successfully developed.However,in general,the current catalyst research model is still empirical,lacking rational optimization design principles of catalyst component;in addition,the existing catalysts for the decomposition of hydrogen from hydrazine hydrate generally have a serious problem of poor durability.However,according to the published literature,scholars from various countries have not paid enough attention to this key issue.In view of this research status,this paper selects a representative Pt-Ni alloy catalyst as the research object,and uses different preparation methods to synthesize unsupported Pt-Ni nanowires and supported Pt-Ni/CeO₂ catalysts,focusing on the phase-microstructure-catalytic performance correlation and deactivation phenomenon of the catalyst are studied and strive to provide an experimental basis for the design and synthesis of high-performance hydrazine hydrate decomposition hydrogen production catalysts.The main research results obtained in the thesis are as follows:（1）The unsupported Pt-Ni nanowire catalyst was synthesized by solvothermal method.Its performance in catalyzing the decomposition of hydrazine hydrate to produce hydrogen is strongly dependent on the composition.The catalyst with optimized composition shows higher catalytic activity and 100%Hydrogen production selectivity.By comparing and analyzing the phase,microstructure and surface adsorption state information of the catalyst before and after use,it is found that the phase change of the catalyst and the excessive adsorption of reaction intermediate products on the catalyst surface are the two possible reasons for catalyst deactivation.This work has certain guiding significance for the optimization design of high-performance hydrazine hydrate decomposition hydrogen production catalyst;（2）The Pt-Ni alloy nanoparticles are loaded on the CeO₂ nanosheets prepared in advance by the co-reduction method,and then the Pt-Ni/CeO₂ supported catalyst is prepared by low-temperature heat treatment.The influence of preparation conditions such as feed ratio,PVP content and heat treatment temperature on the catalytic performance was systematically studied,and the optimal synthesis conditions were determined accordingly.The Pt-Ni/CeO₂ catalyst prepared under optimized conditions can efficiently catalyze the decomposition of hydrazine hydrate to produce hydrogen at a moderate temperature,and its activity is 1.24 times higher than hat of the unsupported Pt-Ni nanowire catalyst.