Thermodynamic Controlled Atomic Pairing: A Potential Window Strategy for Precise Synthesis of Dual-Atom Electrocatalysts via Sequential Electrodeposition

Dual-atom catalysts (DACs) unlock exceptional catalytic potential through maximized atom utilization and synergistic effects, while their atomically precise synthesis remains challenging. Herein, we develop a scalable and atomically precise electrochemical strategy for fabricating precious-metal-based DACs through a potential window-controlled underpotential deposition (UPD) and galvanic replacement cascade. The primary metal sites act as thermodynamically favorable anchoring sites to guide the site-specific assembly of secondary metal atoms. Thermodynamic size screening, through control of the deposition potentials, can effectively exclude larger-sized impurities. This versatile approach is applicable to diverse metals (Pt, Pd, etc.) and tunable supports. As an example, the resulting asymmetrically configured Pt2 DAC anchored on sulfur doped graphite foam (Pt2/SGF) delivered outstanding hydrogen evolution reaction (HER) performance, exhibiting an overpotential of 24.2 mV at 10 mA cm–2. Mechanistic studies reveal that the synergistic electron transfer within the Pt dimer optimizes hydrogen intermediate adsorption (ΔGH* = −0.06 eV), thereby boosting the catalytic activity.