Ordered mesoporous WO3−X possessing electronically conductive framework comparable to carbon framework toward long-term stable cathode supports for fuelcells

Abstract

We report on the successful synthesis of ordered mesoporous WO_3−X with a high conductivity comparable to a mesoporous carbon framework. Ordered mesoporous WO_3−X was prepared using KIT-6 as a hard template. Some WO_3−X particles have negative replica structures of KIT-6 template and the other particles are generated by asymmetric incorporation of phosphotungstic acid inside channels of KIT-6 template. The wall of this mesostructured WO_3−X has a single crystalline structure, which might be responsible for its high conductivity (1.76 S cm⁻¹) comparable to ordered mesoporous carbons (3.0 S cm⁻¹). Pt/mesoporous WO_3−X exhibits a significant tolerance to cycling between 0.6 and 1.3 V_NHE in 0.5 M H₂SO₄ solution, preserving 87% of its initial electrochemical surface area (ECSA) after 1000 cycles. On the contrary, the ECSA of the Pt/C decreased significantly with the number of cycles, resulting in loss of 74% of its initial ECSA.