The Electrocatalytic Hydrogen Evolution And Oxygen Evolution Reaction Performance Of New Hybrid Zeolitic Imidazolate Frameworks And Its Pt-loaded Derivatives

Due to the depletion of globalized fossil fuels and the environmental pollution and greenhouse effect caused by the large-scale consumption of fossil fuels,the search for clean and sustainable energy has become the focus of global scientists.Therefore,hydrogen energy has become the focus of attention because of its advantages of high combustion calorific value,cleanness and no pollution.In many practical production technologies,the production of hydrogen by electrolyzed water has become more and more popular because of its clean and efficient advantages.In the electrocatalytic decomposition of water,hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)are two important semi-reactions.In the course of the reaction,energy input is needed to overcome the obstacle of hydrogen generation from water in the electrochemical process,which is called over-potential.In actual production,an electrocatalyst is required to reduce the overpotential in order to reduce the energy consumption and cost of the production link.In order to replace noble metal electrocatalysts,we have designed and synthesized a series of MOFs and their derivatives to study their structures and mechanisms in electrocatalytic reactions.The main research contents of this tractate are as follows:(1)A group of hybrid zeolite imidazole frameworks(HZIF-2 series)with a novel columnar layer structure were designed and synthesized by using transition metal and imidazole ligands,using 2-propylimidazole or 2-isopropylimidazole as Imidazole ligands successfully synthesized eight isomeric HZIF-2 compounds under similar conditions.The molecular formula is[M5(im)6(TO4)2]n(M=Zn or Co,T=Mo or W,im=2-pim or 2-ipim)?This kind of compound has never been reported before.It is a new topology of HZIFs,which enriches the types of HZIFs.We conducted a series of tests and characterizations on the HZIF-2 series of samples,and found that the HZIF-2 series of samples have good chemical and thermal stability compared to the reported MOFs.And the original sample of HZIF-2-CoMo-pim did not undergo any post-treatment,and it showed excellent catalytic performance of oxygen evolution reaction when it was directly used for electrocatalytic water decomposition.This is an example of an efficient and stable electrocatalyst.(2)A simple method was developed to synthesize Pt nanoparticle-loaded CoMo-bimetallic N-doped carbon material high-efficiency electrocatalyst,and the hybrid zeolite imidazole framework(HZIF-1-CoMo)was uniformly wrapped in situ Pt nanoparticles form the precursor of Pt@HZIF-CoMo to obtain a uniformly dispersed Pt catalyst.The material was calcined at 800? to obtain PtCoMo@NC loaded with 4.70%Pt.Moreover,the metallic cobalt,molybdenum carbide and Pt nanoparticles are highly dispersed and embedded in the mesoporous N-doped carbon matrix of PtCoMo@NC.In the pH range of 1-14,PtCoMo@NC showed HER catalytic performance comparable to commercial 20%Pt/C.Commercial Pt/C cannot be used for a long time,but PtCoMo@NC can achieve continuous electrocatalysis for 12 hours in acid,medium and alkali,and has long-term durability with almost no attenuation.This shows that this type of catalyst has certain industrial application potential.