Synthesis And Electrocatalytic Performance Of Nitrogen-doped Porous Carbon Supported Pt Catalyst

With the development of society,the continuous consumption of fossil fuels has resulted in the depletion of energy resources.A lot of new energy resources have been developed by researchers.Among variously new energy systems,direct methanol fuel cells（DMFC）have gained much attention because of their high energy density,low fuel cost and pollution-free.Pt-based materials still the most effectively electrocatalysts for DMFC.However,the poor activity,stability,and the slow kinetics hinder their commercial application.Therefore,improving the Pt utilization rate and reducing the content of Pt has become one of the most important methods to develop DMFC catalyst.Developing nanostructured carbon materials to support Pt catalyst is an effective way to solve above problems.Thus,a variety of nanostructured carbon materials with large specific surface areas and high chemical stability has been developed.Among them,porous carbon has been attracted much attention due to their high specific surface area and good mass transfer channels.In this paper,a simple one-step template method was used to prepare nitrogen-doped porous carbon and supported Pt nanoparticles as catalysts for DMFC.The research contents as follows:（1）Nitrogen-doped ordered mesoporous carbon sphere（N-OMCS）with a rich hierarchical pore structure was prepared from monodisperse SiO₂ nanospheres array.The Pt nanoparticles were loaded onto N-OMCS,ordered mesoporous polypyrrole sphere（OMPPy S）and commercial carbon black XC-72R at room temperature by using formic acid reduction method to obtain Pt/N-OMCS,Pt/OMPPy S and Pt/XC-72R catalysts,respectively.Pt/N-OMCS shows the largest ECSA(44.9 m²g^-1),methanol oxidation mass activity(386.2 m A mg^-1),anti-toxicity coefficient（0.85）and half-wave potential of oxygen reduction reaction（0.74 V）under acidic conditions.Pt/N-OMCS also has the best methanol oxidation and oxygen reduction stability under duality test.（2）Nitrogen-doped ordered macroporous carbon（N-OMC）was prepared by monodisperse SiO₂ microspheres as template.The catalysts Pt/N-OMC（H₂）and Pt/N-OMC（EG）were obtained by impregnation-hydrogen reduction method and ethylene glycol reduction method at high temperature respectively,and the results show that Pt/N-OMC（H₂）has smaller nanoparticles size.Pt/N-OMC（H₂）has the best methanol oxidation activity,stability and oxygen reduction activity with the largest ECSA(58.5 m²g^-1),methanol oxidation mass activity(505.2 m A mg^-1),anti-toxicity coefficient（0.82）and half-wave potential of oxygen reduction reaction（0.76 V）under acidic conditions..However,Pt/N-OMC（EG）shows the best oxygen reduction activity.The above catalysts are comparable to commercial commercial Pt/C（Johnson Matthey）catalyst.