Construction of core-shell cesium lead bromide-silica by precipitation coating method with applications in aqueous photocatalysis

All-inorganic perovskite cesium lead bromide (CsPbBr3) is hardly applied in direct aqueous photocatalysis due to its instability in water although it has received considerable attention in solar energy conversion. Herein, core-shell cesium lead bromide-silica (CsPbBr3@SiO2) has been prepared by a simple precipitation coating method and applied in visible-light-induced photodegradation of antibiotic residue in water for the first time. The obtained CsPbBr3@SiO2 composite exhibits tunable photocatalytic activity according to the precursor ratios and the maximum achieves at lead bromide/tetramethoxysilane (PbBr2/TMOS) molar ratio of 1:5. Electrochemical and photoluminescence analyses indicate that the introduction of SiO2 results in promoted photo-generated current and reduced impedance, which reduces the photo-induced electron-hole recombination and/or the energy barrier of the interfacial reaction between the formed perovskite particulates. Holes (h+) and superoxide radicals (O2−) are identified as active substances for photodegradation activity. This work demonstrates the application of all-inorganic halide perovskite in efficiently treating refractory contaminants in water, which provides an alternative approach for utilizing inorganic perovskites and new ideas for developing high-efficiency photocatalysts.