Stable and active methanol oxidation via anchored PtRu alloy nanoparticles on NiFe layered double hydroxides

Abstract

Enhancing the catalytic efficiency of the methanol electro-oxidation reaction (MOR) holds paramount importance in expediting the commercialization of direct methanol fuel cells (DMFCs). In this study, we unveil a novel strategy involving the utilization of single-atom dispersed Fe sites within nickel iron layered double hydroxides (NiFe-LDHs) to anchor PtRu nanoparticles, resulting in a uniform distribution. This approach not only leads to increased activity but also introduces a remarkable advancement in stability toward the MOR under alkaline conditions. The incorporation of NiFe-LDHs plays a pivotal role in achieving the consistent dispersion of PtRu nanoparticles through Ru–O(H)–Fe bonding. This innovative technique maximizes the utilization of abundant OH groups, thereby facilitating the efficient oxidative removal of residual CO on Pt sites. Studies of electrochemical tests indicate that the as-fabricated electrocatalyst exhibits superior MOR performance (2031 mA mg⁻¹), excellent CO-poisoning tolerance (I_f/I_b = 3.06) and outstanding cycling stability (200 000 s) compared with commercial PtRu/C catalysts. Utilizing the optimized PtRu/NiFe-LDHs-CB anode catalyst in a direct methanol fuel cell yields an impressive maximum power density of 157 mW cm⁻². This value exceeds that of fuel cells utilizing the commercial PtRu/C catalyst by a factor of 2.3, showcasing a substantial enhancement. Furthermore, these results outperform the previously reported data in this field.