Nanosized Mo-doped CeO2 enhances the electrocatalytic properties of the Pt anode catalyst in direct methanol fuel cells

Abstract

The direct methanol fuel cell is an emerging energy conversion device for which Pt is considered as the state-of-the-art anode catalyst. Herein, we show that the activity and stability of Pt for methanol oxidation can be significantly enhanced using Mo-doped CeO₂ (Ce_1−xMo_xO_2−δ) solid solutions as co-catalysts. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ce_1−xMo_xO_2−δ and Pt in Pt/Ce_1−xMo_xO_2−δ–C catalysts. Among all Pt/Ce_1−xMo_xO_2−δ–C catalysts, the catalyst with a Ce/Mo atomic ratio of 7/3 (Pt/Ce_0.7Mo_0.3O_2−δ–C) exhibits the highest activity, up to 1888.4 mA mg_Pt⁻¹, which is one of the best results reported so far. A direct methanol fuel cell incorporating the Pt/Ce_0.7Mo_0.3O_2−δ–C as the anode catalyst exhibits a maximum power density of 69.4 mW cm⁻², which is 1.8 times that of an analogous fuel cell using the commercial Pt/C-JM as the anode catalyst.