WO3 modification effects on Pt–Pd/WO3-OMC electrocatalysts for formic acid oxidation

• WO3 modified PtPd/WO3-OMC anode catalysts have enhanced the formic acid fuel cell oxidation as compared to Pd/OMC.
• WO3-OMC support improves the electrochemical active surface area and metal dispersion.
• Pd/Pt ratios control the optimum particle size, performance and stability.
• Pd2Pt1/WO3-OMC exhibited superior catalytic performance and stability.

This manuscript presents an experimental investigation of the promotional effects of WO3 on Pt/Pd/WO3-OMC electrocatalysts for oxidation of formic acid. Cyclic voltametry of Pd/WO 3-OMC exhibits 15% higher anodic current activity than that of Pd/OMC. The peak potential is also shifted more than 151 mV in the negative direction. In the bimetallic catalyst samples, the addition of a small amount of Pt improves the performance of PdPt/WO3-OMC significantly. The atomic Pd/Pt ratio of 2, displays the best current density (56.8 mA/cm2), which is 1.2, 1.65 and 5.2 times higher than that of Pd/WO3-OMC, Pd1Pt1/WO3-OMC and Pd1Pt2/WO3-OMC, respectively. It also shows activity over an extended duration without any indication of CO poisoning effects. N2 adsorption/desorption analysis shows that WO3 modification enhances the surface characteristics of OMC with the pore size being slightly decreased from 3.84 nm to3.28 nm. Scanning electron microscopy, x-ray diffraction, transmission electron microscopy analyses reveal that the presence of WO3 enhances the uniform dispersion of active metal(s) on the support surface which is primarily believed to be responsible for superior activity/stability of the Pd2Pt1/WO3-OMC.

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