Preparation And Electrocatalytic Performance Of Pt/CeO₂ Anodic Catalyst For Direct Methanol Fuel Cell

Due to the shortage of resources and environmental pollution,there is an urgent need to find new energy sources to replace traditional energy sources in order to maintain the sustainable development of human society.Direct methanol fuel cells?DMFCs?are considered to have good application prospects in the fields of portable electronic devices and electric vehicles due to their numerous advantages.The carbon carrier used in the DMFCs anode-supported Pt catalyst is susceptible to corrosion and oxidation in extreme environments,which is one of the reasons for preventing its commercial process.In the non-carbon material carrier,the metal oxide carrier has a higher stability than the carbon carrier in the oxidizing environment and a strong interaction with the active component,thereby effectively improving the activity and stability of the catalyst.However,metal oxides have disadvantages such as poor conductivity,which limits their application in DMFCs.Based on CeO₂,based on the better stability,C,C-N and WC were added to enhance the conductivity of the support,and then Pt was added to prepare the catalyst.The research contents are as follows:?1?A CeO₂-C carrier was prepared using a phenolic resin as a carbon source,and a Pt/CeO₂-C catalyst was prepared.The test results show that the Pt/CeO₂ catalyst has larger specific surface area and smaller block size,while the Pt/CeO₂-C catalyst has smaller particle size and can provide more active sites.Good catalytic methanol oxidation performance.?2?The carbon black?Vulcan XC-72?raw material is added to the CeO₂precursor to prepare a CeO₂-C carrier,and a Pt/CeO₂-C catalyst is prepared.The carbon black has good conductivity and high specific surface area.However,carbon black is easily corroded and oxidized during the reaction process,and the stability is poor,while the stability of CeO₂ is good,and the synergistic effect of the two is used to prepare a catalyst with higher performance.The test results show that the peak current density of methanol oxidation of Pt/CeO₂-C catalyst is larger than that of Pt/C and Pt/CeO₂ catalyst.It is shown that the participation of C significantly increases the electrocatalytic activity.?3?Melamine has a high nitrogen content and is relatively inexpensive,and is one of the preferred materials for carbon and nitrogen.In this paper,the CeO₂-C-N precursor was prepared by hydrothermal synthesis method,and the CeO₂-C-N carrier was obtained after high temperature cracking of oxygen,and Pt/CeO₂-C-N catalyst was prepared.The results show that the Pt/CeO₂-C-N catalyst has a higher electrochemical activity than the Pt/CeO₂ catalyst,indicating that the Ectrochemical active surface area?ECSA?has higher density and better stability of the methanol oxidation peak current.The reason is that N in the carrier CeO₂-C-N is mainly pyridine N,pyrrole N,and graphite type N.Pyridine N and pyrrole N can enhance the anchoring effect of Pt particles,while graphite type N is beneficial to the conductivity of the carrier,and activates water to generate hydroxyl radicals at lower potentials,promotes the removal of carbonaceous species such as COads,and enhances the carrier Stability.?4?WC has the catalytic activity of Pt-like.Adding WC to Pt-based catalyst can reduce the amount of Pt and reduce the cost,while WC also has high stability and conductivity.The Pt/CeO₂-WC catalyst was prepared by combining CeO₂ with WC.The test results show that the peak oxidation current of methanol oxidation of Pt/CeO₂-WC catalyst is larger than that of Pt/WC catalyst and Pt/CeO₂ catalyst,indicating that methanol molecules are more effectively oxidized on Pt/CeO₂-WC.Because WC has platinum-like catalytic activity,it can promote water to decompose hydroxyl radicals and accelerate the oxidation and desorption of COads.At the same time,the oxygen vacancies of CeO₂ provide active sites for adsorbing CO and release more active sites of Pt.