Spontaneous Alkaline Water Electrolysis Driven by the “OH-Baton”

Nano-metal particles integrating with single-atom catalysts (NMP-SACs) have been constructed recently for accelerated alkaline hydrogen evolution reaction (HER). However, the design of NMP-SACs primarily aims at the separate adsorption of *OH and H*, while neglecting the *OH desorption, causing *OH blockage and slow kinetics. To address this, Mo₂C is introduced to NMP-SACs (e.g., Pt nanoparticles-Pt atom, Pt_n-Pt₁) by a “one-step dual-confinement pyrolysis” strategy for Pt_n-Pt_1@Mo2C, where Pt₁ precisely confined by Mo₂C with Pt_n remaining adjacent to Pt₁@Mo₂C. Experiments and calculations demonstrate that Mo₂C acting as an “OH-baton” helps overcome *OH blockage on Pt₁, accelerating the separation of H* and *OH and thus promoting spontaneous alkaline water dissociation. Thus, the supported Pt_n-Pt₁@Mo₂C achieves a significantly lower overpotential (η₁₀ = 24 mV) and a more than seven times higher mass activity (MA₁₀₀ = 4.33 mA µg Pt⁻¹) than Pt_n-Pt₁ in alkaline. The alkaline anion-exchange membrane water electrolyzer (AEMWE) delivers a low cell voltage of 1.91 V and durable 120 h of electrolysis at 1.0 A cm⁻². This work proposes a new insight for introducing an “OH-baton” in a dual-site catalyst system to achieve spontaneous alkaline water dissociation.