Bimetallic PtIr nanoalloy on TiO2-based solid solution oxide with enhanced oxygen reduction and ethanol electro-oxidation performance in direct ethanol fuel cells

Abstract

Elevating the electrocatalytic performance of both cathode and anode catalysts is critical to the advancement and widespread utilization of low-temperature fuel cells. Herein, we report an effective Pt₃Ir/Ti_0.7W_0.3O₂ catalyst for the oxygen reduction reaction (ORR) and ethanol electro-oxidation reaction (EOR) using a facile reduction process. In terms of the ORR, the Pt₃Ir/Ti_0.7W_0.3O₂ catalyst shows a specific activity of 0.99 mA cm⁻² and a mass activity of 0.802 A mg_Pt⁻¹, which are 6.72- and 7.22-fold improvements compared to the commercial Pt/C catalyst. The result of the 10 000-cycle accelerated durability test (ADT) under an O₂ atmosphere indicates that the impressive ORR stability of the Pt₃Ir/Ti_0.7W_0.3O₂ catalyst with a decay of 12.26% in mass activity, against a large decrease of 45.76% for Pt/C (E-TEK). In addition, the Pt₃Ir/Ti_0.7W_0.3O₂ catalyst exhibits better EOR performance compared to the Pt/C catalyst with a high mass activity (810.03 mA mg_Pt⁻¹) along with superior CO-tolerant ability and durability. The improved electrocatalytic performance of the Pt₃Ir/Ti_0.7W_0.3O₂ catalyst is attributed to the beneficial effect of alloying Pt with Ir and the merit of the TiO₂-based support along with the synergistic effect between the Pt₃Ir alloy and Ti_0.7W_0.3O₂ support. These findings can offer a robust catalyst platform for fuel cells, solar cells, and biosensors.