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

Abstract

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 oxygenlinked 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 MoO 2 phase, while the nitrogen modulator is beneficial to stabilizing MoO 3 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.

Structural Reconstruction Chemistry for Alkaline Oxygen Evolution Catalysts

“…[15,16] Since the OER involves a multi-step, four-electron transfer process, the kinetics of water splitting are restrained. [17][18][19][20][21][22] Developing highly efficient oxygen evolution electrocatalysts to accelerate the reaction kinetics of OER is urgently needed.…”