Boosting Water Dissociation Kinetics on GaOOH Nanosheets by Transition Metal Doping

The development of cost-efficient and high-performance electrocatalysts for water splitting has long been a key goal in the pursuit of converting power to clean hydrogen energy. Herein, Fe-doped GaOOH (Fe-GaOOH) is synthesized on the nickel foam through a hydrothermal method. The obtained Fe-GaOOH displays high hydrogen evolution reaction (HER) activity with an ultralow overpotential of 73 mV@10 mA cm^-2 in 1 M KOH media. Additionally, it demonstrates remarkable stability, maintaining performance for 200 h at 10 mA cm^-2. When integrated into a water electrolyzer, the Fe-GaOOH self-supporting electrode requires only a cell voltage of just 1.57 V to reach a current density of 10 mA cm^-2. In situ experiments and density functional theory calculations indicate that Fe-GaOOH provides more electrons to the oxygen atoms that adsorb H₂O, while also enhancing the *H coverage, which, in turn, lowers the energy barriers for water dissociation and hydrogen desorption, eventually promoting the HER. It was found that Co, Ni, and Mn dopants in GaOOH exhibit the same effect, indicating that transition metal doping is considered a common factor in regulating catalytic performance.