A CsPbBr3/TiO2 Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

Halide perovskites have attracted great attention in the fields of photovoltaics, LEDs, lasers, and most recently photocatalysis, owing to their unique optoelectronic properties. The all-inorganic halide perovskite CsPbBr3 /TiO2 composite material catalyzes selective benzyl alcohol oxidation to benzaldehyde under visible-light illumination. The catalyst, which is prepared by a facile wet-impregnation method, shows very good selectivity towards benzaldehyde (>99 % at 50 % conversion). Action spectra and electron spin resonance (ESR) studies reveal that photoexcited electrons formed within CsPbBr3 upon visible-light illumination take part in the reaction via reduction of oxygen to form superoxide radicals. The detailed post-catalysis characterization by UV/Vis and X-ray photoelectron spectroscopy, X-ray diffraction, and high-angle annular dark-field scanning transmission electron microscopy studies further demonstrated the good stability of CsPbBr3 in terms of morphology and crystal structure under the reaction conditions. This study sheds light on promising new photocatalytic applications of halide perovskites.