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

Abstract

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.