Aboundent oxygen defects in CoFe-LDH derivatives for enhanced photo-thermal synergistic catalytic hydrogen production from NaBH₄

Two-dimensional catalysts, which are sensitive to visible light and have a photothermal effect, can be used to catalyse the release of H₂ from sodium borohydride (NaBH₄) are being actively explored in energy saving systems. In this work, oxygen vacancy enriched two-dimensional CoFe-layered double hydroxide (CoFe-LDH) derivatives (named as CoFe-x °C, x = 200–500) have been explored for NaBH₄ hydrolysis catalyzed by photo-thermal synergy without external heat source. The CoFe-300 °C presents its initial hexagonal lamellar structure and has the highest concentration of oxygen vacancy. These unique properties guarantee its excellent photo-thermal synergistic catalytic performance, achieving hydrogen production rate of 1877.5 mmol g⁻¹ h⁻¹, and maintains high efficiency after 5 cycles. This enhanced photo-thermal synergistic catalytic mechanism is the •OH (generated from h⁺ and H₂O) attacks BH₄⁻ (absorbed on O_v sites) to produce H₂, the heat from photothermal conversion accelerates the adsorption ability and attacking rate. This study opens a new strategy for the synergistic photo-thermal catalytic hydrolysis of NaBH₄.