Phosphorus-oxygen groups drive surface-confined growth of high-valence amorphous transition-metal oxides on carbon...

Beyond the morphological study, the key to optimizing the performance of carbon-supported oxides in oxygen evolution reaction (OER) lies in phase engineering and electronic structure regulation. In this study, the surface-confined growth of high-valence amorphous transition-metal oxides on carbon surface is achieved by introducing phosphorus-oxygen groups, which strongly adsorb transition-metal ions and inhibit atomic rearrangement during heat treatment. Experimental characterization revealed that the oxides remained amorphous over a wide temperature range (up to 550 °C). Density functional theory (DFT) calculations and electronic structure analysis revealed the high electron-withdrawing capacity of the phosphorus-oxygen groups, which led to an increase in the valence state of transition metals. The obtained catalysts show excellent OER performance due to the matched OH^- adsorption and deprotonation, requiring an overpotential of 251 mV to reach 10 mA cm^-2. This study highlights the importance of phase engineering and electronic structure regulation in designing carbon-supported oxides, providing a universal method to achieve amorphization and electronic modulation of transition-metal oxides.