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Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions (OERs). Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts. Herein, Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mA cm^-2. Additionally, it had an overpotential of 260 mV (glassy carbon) or 215 mV (nickel foam), which was 78 mV lower than that of IrO₂ (338 mV). In situ, Raman spectroscopy revealed the transformation process of CoOOH. Calculations using the density functional theory showed that during OER, doped Mo increased themore » spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process, which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials. Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.« less

Developing a fast and highly active oxygen evolution reaction (OER) catalyst to change energy kinetics technology is essential for making clean energy. Herein, we prepare three-dimensional (3D) hollow Mo-doped amorphous FeOOH (Mo-FeOOH) based on the precatalyst MoS₂/FeC₂O₄ via in situ reconstruction strategy. Mo-FeOOH exhibits promising OER performance. Specifically, it has an overpotential of 285 mV and a durability of 15 h at 10 mA cm^–2. Characterizations indicate that Mo was included inside the FeOOH lattice, and it not only modifies the electronic energy levels of FeOOH but also effectively raises the inherent activity of FeOOH for OER. Additionally, in situmore » Raman analysis indicates that FeC₂O₄ gradually transforms into the FeOOH active site throughout the OER process. Finally, this study provides ideas for designing in situ reconstruction strategies to prepare heteroatom doping catalysts for high electrochemical activity.« less