Vanadium carbide to boost Palladium as anodic catalyst for direct ethanol fuel cell

The direct ethanol fuel cell is a hopeful clean energy technology to replace fossil fuels. One of the most important and effective factors in fuel cell technology is finding convenient and affordable catalysts. Two major problems are the poisoning of the electrocatalysts used on the anode side, by intermediate the ethanol oxidation reaction; and cleavage of carbon-carbon bond in ethanol. It is a good scenario to use promoters along with noble metals as the main component of the catalyst. Vanadium carbide (VC) is an choice as promoter of palladium. It has properties such as electrochemical stability in acidic and basic environments, resistance to intoxication and low cost. In this research, vanadium carbide was fabricated with high surface area from vanadium oxide as the precursor by the solution combustion synthesis. Then, palladium was loaded onto the surface of as-synthesised vanadium carbide by wet integration method and chemical reduction followed with NaBH۴. It was investigated the catalytic activity of the obtained composite towards ethanol oxidation by electrochemical studies such as cyclic voltammetry and chronoamperometry. The studies showed that Pd/VC has more acceptable electro-catalytic properties, such as increased current than Pd ( about ۲۰ times more) due to anti-poisoning behavior of VC. It is seems that the porous structure of VC caused the high dispersion of Pd; and improved electrochemical surface area. Also, the VC helps Pd to eliminate the compounds blocking the electrocatalyst active site (like CO) with switching between vanadium valances in a redox cycle.

Keywords:

Vanadium Carbide , Ethanol oxidation , anti-poisoning , electrochemistry ,