Preparation Of Nickel Compounds/Polypyrrole/Graphene Oxide Nanosheets And Its Application To Electrocatalysts

Direct fuel cells were widely concerned for its high efficiency and low/zero emission,and were expected to address high-energy demands,fossil energy depletions and environment pollution in the world.Noble-metal materials such as nickel compounds were expected to be used as electrocatalysts in fuel cells in place of noble metal because of its low price and abounding storage.In alkaline medium,nickel compounds was easily electrochemically oxidized to Ni???,then Ni???were reacted with methnol or urea.Polypyrrole/graphe oxide nanosheets have attracted worldwild attention on electrocatalysts due to its high electroconductivity,excellent environment and specific surface area.Hence,nickel compounds founctionalized polypyrrole/grapheme oxide nanosheets has high conductivity,good stability and large specific surface area,meanwhile,the nanosheets possess electrocatalysis of methanol and urea,which was considered to be applied to direct methanol fuel cells or direct urea fuel cells.In this paper,NiS/Ni?OH?₂ nanosheets with the thinness less than 10 nm were in-situ grown on polypyrrole/graphene oxide via a simple solvothermal method because of the coordination interaction between Ni²⁺and–NH-segments in PPy chains,hierarchical NiS/Ni?OH?₂@PPy/GO nanosheets exhibited the excellent two-dimension meterial,specific surface area and conductivity and electrochemical catalysis activity towards methanol oxidation reaction,which reaveal a potential application to direct methanol fuel cells.The mechanism of methanol oxidation reaction on the surface of NiS/Ni?OH?₂@PPy/GO nanosheets modified glassy carbon electrode were investigated in detail,where methanol were mainly oxided on Ni???oxide surface through electrooxidation and Ni???was used as the active surface of methanol oxidation reaction.Secondly,Ni?OH?₂ nanoparticles with a diameter of 2-3 nm and Ni?OH?₂nanosheets with a thinness of 15-20 nm were successfully immobilized on the surface of polypyrrole/graphene oxide via a simple strategy.Hierachical Ni?OH?₂/PPy/GO nanosheets can act as electrochemical catalysts for urea oxidation reaction in alkaline medium where the urea were oxidized by the Ni???on the surface of PPy/GO and been applied to urea-rich wastewater disposal,hydrogen production and direct urea fuel cells in future.