Structures and photocatalytic activities of bismuth oxyhalides nanoparticles developed by utilizing a simple reaction

•Bi2O3 and NH4X were used as raw materials to explore new preparation method of bismuth oxyhalides.•The effects of ammonium halide concentration, temperature and time on the reaction were investigated.•The bismuth oxyiodide nanobook was constructed in hydrothermal reactor to form the photocatalytic degradation system.•Well-crystalized bismuth oxybromide reach to decompose the organic pollutants over three smooth cycles under white light irradiation with 3.8% efficiency loss.