Regulating the Oxygen Evolution Mechanism through In Situ Reconstruction of Ru-Modified Manganese Oxybromide

Regulating the oxygen evolution reaction (OER) mechanism presents a promising yet challenging approach to address the performance-stability trade-off of acidic water oxidation catalysts. Here we demonstrate the regulation of the OER mechanism through in situ surface reconstruction of manganese oxybromides (MOB) catalysts modified with single-atom ruthenium (Ru-MOB). In situ Raman spectroscopy reveals that Ru incorporation intensifies the inherent, reversible surface reconstruction of MOB, resulting in the formation of a γ-MnO2 layer with an onset potential approximately 100 mV lower. Various operando/in situ characterizations and theoretical calculations show that the reconstructed Ru-MOB significantly suppresses the lattice oxygen mechanism while simultaneously enhancing the adsorbate evolution mechanism. In an electrochemical cell, the reconstructed Ru-MOB drives acidic OER with an overpotential about 90 mV lower at 10 mA cm–2 compared to pure MOB, and it shows negligible performance degradation for over 1400 h. Our work offers a design strategy for the future development of acidic OER catalysts.