A robust strategy to boost the proton transfer of heterogeneous catalysts for efficient and sustainable water oxidation towards practical applications

Abstract

Owing to the much larger mass of proton compared to that of an electron, the oxygen evolution reaction (OER) on heterogeneous electrocatalysts usually undergoes slow proton/fast electron transfer, which greatly limits the OER performance. Boosting the proton transfer may break this limitation but remains a huge challenge. Here, a robust yet facile strategy is proposed to accelerate the proton transfer of self-supported CoNi–hydroxides (CoNi–OH) via the incorporation of La³⁺ cations. Both deuterium kinetic isotope effects and atom-proton-transfer tests reveal that the Lewis basic sites provided by La³⁺ can act like proton relays for promoting the electron–proton transfer process, and thus the overall kinetics of OER. Consequently, under industrial operating conditions (i.e., at 60 °C, in 6 M KOH), at a small overpotential of 242 mV, the CoNi–OH with La³⁺ yields a large current density of 1500 mA cm⁻², 16.3-fold larger than the counterpart without La³⁺. Moreover, we discovered that the corrosion of CoNi–OH resulting from the slow proton transfer can be significantly suppressed by La³⁺, improving stability under such industrial conditions. This work paves new avenues to achieve the efficient and sustainable OER towards practical applications via the acceleration of proton transfer.