Coupling Methanol Oxidation with Hydrogen Evolution on Bifunctional Co‐Doped Rh Electrocatalyst for Efficient Hydrogen Generation

Abstract Efficient hydrogen production from electrochemical overall water splitting requires high‐performance electrocatalysts for hydrogen evolution reaction (HER) and a fast oxidation reaction to replace sluggish oxygen evolution reaction. Herein, Co‐doped Rh nanoparticles are thus grown on carbon black using Co nanosheets as the bridge. These nanoparticles with a size of ≈1.94 nm exhibit the overpotential of as low as 2 mV at 10 mA cm −2 for the HER, and a mass activity of as high as 889 mA mg −1 for the methanol oxidation reaction (MOR) in alkaline media. As confirmed by density functional theory simulations, such excellent activity originates from Co‐doping, which reduces reaction energy barriers for both the rate‐determining step of a Volmer process during the HER and the conversion of *CO to COOH* during the MOR (namely the enhanced adsorption of H 2 O and COOH*). Coupling boosted HER on the cathode with accelerated MOR on the anode, efficient H 2 generation is achieved. This two‐electrode cell only requires a cell voltage of 1.545 V at 10 mA cm −2 with impressive long‐life cycling stability. Such performance even outperforms that of commercial Pt/C || IrO 2 cell. This study offers a new strategy to achieve efficient HER from overall water splitting.