Frustrated Lewis pair chemistry in 2D CeO2 for efficient alkaline hydrogen evolution†

Abstract

The alkaline hydrogen evolution reaction (HER) is pivotal for sustainable energy production but is hindered by sluggish kinetics due to the necessity of water dissociation to supply protons, which presents a high energy barrier. To overcome this challenge, a novel approach is proposed involving the introduction and tuning of oxygen vacancies on the surface of CeO₂ to construct and control frustrated Lewis pairs (FLPs) with dual active sites for enhanced water dissociation. First-principles calculations reveal that increasing the number of oxygen vacancies significantly improves the quantity and activity of FLP sites for efficient water dissociation. Guided by these calculations, 2D CeO₂ nanosheets with varying concentrations of oxygen vacancies were synthesized, showing that those with the highest vacancy content exhibit exceptional HER performance, with an overpotential of 132 mV and a Tafel slope of 73 mV dec⁻¹. These findings validate the theoretical model and underscore the potential of 2D CeO₂ with FLP active sites as effective and stable HER catalysts. This study is anticipated to inform the development of advanced catalysts with FLP active sites for hydrogen evolution reactions in alkaline media.