Study On Se/Ru As Cathode Catalyst For Direct Methanol Fuel Cell

Direct methanol fuel cell has advantages of simple structure and easy handling of fuel.It is the potential power source for electric vehicles and portable electronic devices.One of the reasons hindering the commercialization process of direct methanol fuel cell is that the widely used Pt cathode catalyst is sensitive to methanol.So methanol migrated from anode to cathode takes place oxidation reaction at Pt cathode and produces a mixed potential,leading to the cathode polarization.Therefore study on the cathode electrocatalyst having both high oxygen reduction catalytic activity and strong methanol tolerance ability is one of the important topics of direct methanol fuel cell.In this article,preparation method,structure,oxygen electroreduction catalytic activity and methanol tolerance performance of nano-sized Se/Ru were investigated.A new method for the preparation of nano-Se/Ru electrocatalyst was developed.In this method,metallic nano-Ru particles react with SeO₂ solution in an atmosphere of H₂ to induce the formation of nano-Se/Ru catalyst.This method has the advantages of mild reaction conditions(at room temperature,atmospheric pressure),non-toxic and non-polluting,high yield,good repeatability,low cost, and easy to scale up.The obtained Se/Ru catalyst was characterized by XRD, TEM,XPS CV and CO probe adsorption.Its electro-catalytic activity for oxygen reduction and methanol tolerance performance were investigated.It was found that the average particle size of the prepared Se/Ru catalyst is about 4.5nm,Ru in Se/Ru is in the metallic state,and there exist chemical bonds between Se and Ru. Se covers most of the surface atoms of Ru and prevents them from being oxidized. The bare metallic Ru atoms surrounded by Se atoms may be the catalytic active site for oxygen reduction reaction.Se/Ru shows high catalytic activity for oxygen electroreduction and strong tolerance to methanol.The initial potential of oxygen reduction on Se/Ru is about 0.9V.Se/Ru is not sensitive to 1mol/L methanol.Proton exchange membrane fuel cell and direct methanol fuel cell were prepared using Se/Ru as cathode catalyst.The test results of the cell performance show that the current density of the proton exchange membrane fuel cell is 657mA/cm² at the cell voltage of 0.40V and the operation temperature of 80℃. The performance of the direct methanol fuel cell dose not vary with the anode methanol concentration below 12mol/L.The performance of Se/Ru as PEMFC and DMFC cathode prepared by this study is obviously higher than the Se/Ru cathode prepared using the literature reported method in organic solvent system.