Effect of temperature and reaction time during solvothermal synthesis of BiOCl on microspheres formation: implications in the photocatalytic oxidation of gallic acid under simulated solar radiation

Abstract

Synthesis and characterization of bismuth oxychloride (BiOCl) has received much attention due to its excellent photocatalytic properties, and low toxicity that allow its potential application for environmental decontamination processes. In this work, experimental conditions (temperature and reaction time) were established to synthesize BiOCl microspheres by a solvothermal method with high photocatalytic efficiency on the degradation of 3,4,5-trihydroxybenzoic acid (gallic acid). BiOCl materials were synthesized according to a design of experiment (DoE) where temperature and reaction time were selected as varying parameters. Obtained BiOCl materials with the highest and lowest degradation toward gallic acid, were characterized using several techniques. Results showed that the applied temperature is the most important parameter during solvothermal synthesis, which influences not only morphology and structure of BiOCl, but also its thermal stability and optical properties. Response surface methodology (RSM) analysis indicated that the highest photocatalytic efficiency of synthesized BiOCl material, is obtained when the temperature and reaction time are fixed at 155 °C and 18 h, respectively. Finally, a reaction mechanism of photocatalytic oxidation of gallic acid was proposed based on an experimental tests by adding different radical’ scavengers.