Synthesis Of Hollow Hemisphere Carbon-supported PTSN Catalyst And Its Electrocatalytic Properties

The long-term use of fossil fuels has caused serious environmental pollution.The development of a clean and sustainable energy system has become a hot spot for many scholars.Some small organic molecules containing hydrogen such as ethanol,methanol,ethylene glycol and glycerol,etc directly as fuel could be good substitutes owing to their high energy density,low cost and convenient storage.Amongst various candidates,ethanol as fuel can be a promising substitute for fossil fuels because ethanol as power source has the advantages of high energy density(8.0 kWh·kg-1),pollution free and renewable.Ethanol fuel cell produce energy by using the ethanol oxidation reaction,nevertheless ethanol oxidation reaction(EOR)undergoes slow electrooxidation kinetics because of generating acetic acid,acetaldehyde,and carbon monoxide(COad)during the ethanol oxidation.The catalyzer of EOR requires high catalytic performance to make the strong C-C bond breaking from ethanol.Hollow carbon hemispheres(HCHs)is a prevailing carbon support material for the catalysts due to their unique opening three-dimensional channels,a large number of micropores and mesopores and high electrochemical active surface area etc.Nitrogen-doped carbon materials exhibit excellent electrocatalytic activity because electron-rich nitrogen doping can modify the surface structure of carbon materials and provide more active sites on carbon material surface for metal nanoparticle deposition.In this work,we designed a kind of deeply graphitized hollow carbon hemispheres(HCHs)with 3D structure using asphalt as carbon source and nano silica as hard template.Then PtSn nanoparticles were deposited on HCH.In addition,we doped nitrogen in the hollow hemisphere carbon,and controlled the doping of nitrogen through the amount of nitrogen source,so as to realize the tunable size and distribution of metal nanoparticles.They were all studied for ethanol electro-oxidation reaction in acid solution.The results show that the catalytic activity of the PtSn/HCH catalyst is obviously higher than that of carbon black as the support(PtSn/HCH).The value of the current density in PtSn/HCH is 100mA·mg pt-1 bigger than that of PtSn/C,The value of the stationary current density in PtSn/HCH is about 3 times of PtSn/C.And when the adding nitrogen source is half of the carbon source in HCHs the synthesis process,the amount of nitrogen doping reaches the maximum,and that loading PtSn has the very strong catalytic activity.The value of the current density and the stationary current density in PtSn/HCH-N0.5 are up to 430 mA·mgPt-1 and 77 mA·mgPt-1 in 1 M ethanol solution,which are about 3 times and 20 times of PtSn/C.