Transition metal single-atoms anchored on Mo

Alkaline anion-exchange membrane fuel cells (AEMFCs) have garnered significant attention as promising energy conversion devices, yet their development remains hindered by the scarcity of efficient platinum-free electrocatalysts for the hydrogen oxidation reaction (HOR). Here, we systematically investigated the HOR catalytic performance of transition metal single-atoms supported by Mo2C (TM-Mo2C, TM = Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Ir, Pt) using first-principles density functional theory (DFT) calculations. Theoretical calculations indicate that the integration of TM atoms with Mo2C substrates modulates the electronic structure, and establishes dual active sites comprising TM and adjacent Mo atoms. This synergistic configuration optimizes the adsorption free energies of key intermediates (H* and OH*), thereby regulating HOR activity. Volcano-shaped relationships are identified between the catalytic activity of TM-Mo2C and the adsorption free energies of H* and OH*. Notably, Ru-Mo2C exhibits ultralow free energy barriers for HOR due to its balanced H* and OH* adsorption strengths, demonstrating superior catalytic performance. Additionally, Ru-Mo2C shows excellent thermodynamic and electrochemical stability, supported by its negative formation energy and high oxidation potential. These findings highlight Ru-Mo2C as a promising high-performance HOR catalyst for AEMFCs, offering theoretical guidance for the rational design of efficient Pt-free electrocatalysts.