Dual-metal-doped zinc spinels as efficient electrocatalysts for methanol-assisted hydrogen evolution: Combined DFT and experimental insight

We report the rational design and synthesis of noble–nonprecious metal co-doped zinc cobaltite nanostructured electrocatalysts (NECats), ZnPtxMoxCo2−2xO4@Nifoamx≤0.08[jls-end-space/], via a facile hydrothermal strategy. X-ray diffraction confirms the formation of a cubic spinel oxide phase, while scanning electron microscopy reveals hierarchical microspheres composed of interconnected nanoneedles, providing abundant active sites and accelerating charge transport for electrocatalysis. Among the series, the optimized composition (x = 0.06) delivers outstanding hydrogen evolution reaction (HER) performance, achieving a low overpotential of only 70 mV at 10 mA/cm2 with a Tafel slope of 117.81 mV/dec, comparable to benchmark catalysts such as pure Pt. The catalyst further exhibits excellent durability, maintaining stable operation at −20 mA/cm2 for 72 h. In methanol oxidation reaction (MOR)-assisted alkaline media, the same catalyst requires a low potential of 1.34 V to reach 10 mA/cm2. When integrated into a two-electrode system, the bifunctional (Formula presented) catalyst enables efficient overall methanol-assisted water electrolysis, delivering a low cell voltage of 1.48 V at 10 mA/cm2. Density Functional Theory (DFT) calculations reveal a strong synergistic interaction among Pt, Mo, and Co active centers, which optimizes the hydrogen adsorption free energy (ΔG_H∗) and significantly enhances HER kinetics. This work highlights the effectiveness of multi-active-site engineering in spinel oxides, which provides a rational pathway for developing high-performance, cost-efficient bifunctional electrocatalysts with high stability, advancing sustainable hydrogen production and energy-efficient electrolysis technologies.