Boron/Nitrogen-Induced Surface Environment Modulation for Favorable Phase and Valence toward Efficient Oxygen Evolution

For electrocatalytic oxygen evolution reactions (OERs), surface microenvironment associated with the physicochemical states of nanocatalysts acts as a crucial role for determining catalytic performance. Rational modulation of oxygen-linked surface microenvironment (OLSME) for favorable phase and valence is a promising strategy for promoting OER activities, particularly for these intrinsically inert metal oxide catalysts. As a proof-of-concept, molybdenum oxides are selected as a representative catalyst model and the anionic boron/nitrogen species are selected as modulators for reducing lattice oxygen and optimizing adsorbed oxygen, accompanied by the formation of metal–boron/nitrogen interactions. It is concluded that the boron modulator tends to induce the formation of the MoO₂ phase, while the nitrogen modulator is beneficial to stabilizing MoO₃ phase. By virtue of comprehensive comparison of OER activities, the boron modulator is more favorable for enhancing OER performance, with a lower overpotential of 298 mV than that for the nitrogen modulator (310 mV) at a current density of 10 mA cm^–2, without any obvious performance decay for continuous operation up to 50 h in the alkaline solution. It is expected that this work offers some insights on the OLSME engineering and provides possibilities for promoting activities of these inactive metal oxide electrocatalysts.