Preparation Of Low Platinum Catalyst For Direct Methanol Fuel Cell And Its Electrochemical Performance

Direct methanol fuel cell is an ideal power source for portable mobile devices and new energy electric vehicles due to its advantages of low operating temperature,high energy density,easy access and storage of fuel,and no harmful waste emission.It is expected to make significant progress in practical application in the future.Direct methanol fuel cell is an electrochemical power generation device which converts the chemical energy stored in methanol into electric energy.The methanol oxidation efficiency on the anode determines the performance and cost of the entire battery to some extent.At this stage,the most effective methanol anode catalyst is still platinum.The precious metal platinum is expensive and their reserves are scarce.The commercial platinum carbon catalysts currently used have poor activity and low utilization efficiency of metal platinum.In the actual working process,it is easy to combine with intermediate species to reduce the catalyst activity.At the same time,the carbon carrier material is not resistant to corrosion,which will further reduce its stability.This series of reasons determines that commercial platinum carbon is far from meeting the conditions for large-scale commercialization.Therefore,it is urgent for researchers to develop platinum-based catalysts with high platinum utilization efficiency,corrosion resistance and high stability.In the method of improving the utilization efficiency of platinum,it is proved to be effective to combine platinum with other transition metals to form alloy materials;In addition,building nanomaterials with core-shell structures is an efficient way to maximize the use of platinum.It is of great practical significance to prepare low platinum efficient catalysts by effective means for promoting the commercialization of direct methanol fuel cells.Based on the above considerations,a core-shell structure catalyst was designed by pulsed electrodeposition with titanium nitride as the core and platinum deposited on the titanium nitride as core.At the same time,the performance of the catalyst was improved by doping other transition metals in titanium nitride.Compared with other transition metals,the binary nitride carrier doped with cobalt had higher catalytic activity after depositing platinum.The amount of platinum was reduced by pulsed electrodeposition,and the core-shell structure can also expose more active sites,which can make the full use of the platinum.The mass activity of Ti_0.9Co_0.1N@Pt/NCNTS was 757.31 m A mg¹,which was approximately 3.74 times higher than the commercial platinum carbon.In the stability test,the core-shell catalyst also had higher stability and anti-poisoning performance.In addition,Platinum-copper alloy was obtained by a simple solvent heating method.The material had high methanol oxidation activity,and the mass activity of Pt₁₄Cu₈₆ NWs was 939.17 m A mg,which was approximately 4.6 times higher than commercial Pt/C catalyst.The introduction of non-precious metal copper can not only reduce the amount of platinum,but also accelerate the reaction as methanol adsorption center.The platinum-copper alloy nanowires catalyst had excellent methanol oxidation activity and stability.The Pt-Ni alloy with thorn ball structure was obtained by reducing platinum and nickel by glucose.Nickel-based materials have a certain surface oxidation ability.The introduction of nickel metal can not only improve the activity of the alloy catalyst but also improve the stability of the materials.The mass activity of platinum-nickel alloy Pt₃Ni-2/C was 339.21 m A mg,which was approximately 1.6 times higher than commercial Pt/C catalyst.At the same time,this material had the cycle stability and the anti-poisoning performance which was far more than commercial platinum-carbon in the stability test.