Reduced Cu/Pt–HCa2Ta3O10 Perovskite Nanosheets for Sunlight‐Driven Conversion of CO2 into Valuable Fuels

Abstract

Reduced perovskite HCa2Ta3O10 nanosheets loaded with Pt and Cu are synthesized for sunlight‐driven conversion of CO2 with water vapor into valuable fuels. Perovskite nanosheets are prepared by exfoliating layered perovskite CsCa2Ta3O10 via tetra butyl ammonium ion exchange, followed by liquid ultrasonic exfoliation. The obtained nanosheets exhibits a high specific surface area (>200 m2 g−1). The photocatalytic performance of the resulting reduced perovskite nanosheets is evaluated for CO2 photoreduction under sunlight in the presence of saturated water vapor. The reduced nanosheets exhibit much higher photoactivity than the nonreduced ones. This can be ascribed to their unique structure. The hydrogen treatment in the presence of platinum induces a considerable amount of Ta+4 and oxygen vacancies, which apparently improves the visible light absorption of perovskite nanosheets. Moreover, the introduction of CuO nanoparticles significantly improves the electron–hole separation through the formation of a p–n junction. It also enhances the adsorption of CO2 and stabilizes C1 intermediates which are favorable for CC coupling to form C2 products (e.g., ethanol). The formation rates of ethanol and methanol are 113 and 7.4 µmol g−1 h−1, respectively, while only methanol is obtained at the rate of 125.9 µmol g−1 h−1 in the absence of CuO nanoparticles.