Preparation of MOF-derived molybdenum-carbide-modified PtCu nano-alloy catalysts and their methanol oxidation performance

Abstract

Direct methanol fuel cells (DMFC) are a promising new energy source. However, the lack of high-performance and low-cost methanol oxidation electrocatalysts hinders their commercial application. Firstly, we successfully prepared NENU-5-derived molybdenum carbide material (Cu-MoC) via a co-precipitation and high-temperature carbonization method using a material composed of a copper-based metal–organic skeleton and a molybdenum-based carbide as the main body. Secondly, PtCu nano-alloy catalysts (Pt/Cu-MoC) were prepared using a unique, spontaneous single replacement reaction after metal–organic skeleton (MOF) carbonization. Through the synergistic effect between Pt and Cu and the strong interaction between Mo₂C and PtCu, the electronic structure of the Pt is modified, the energy of the d-band center is reduced, electron exchange is accelerated, and catalytic activity is enhanced. Compared with a commercial Pt/C catalyst in alkaline environments, the Pt_0.10/Cu-MoC catalyst has a better MOR catalytic activity (563.25 mA mg_Pt⁻¹), which is 1.5 times higher than that of commercial Pt/C (376.67 mA mg_Pt⁻¹). The Pt_0.10/Cu-MoC catalyst has an onset potential for CO oxidation that is 16 mV lower than that of commercial Pt/C, indicating better resistance to CO poisoning. Exploring carbon materials derived from MOFs with excellent junction support and using them as carriers to prepare Pt-based catalysts is a practical and feasible approach. It provides a way to develop new Pt-based catalysts that perform efficient MOR.