Controlled vertical growing of Bi2O3 nano sheets on diatomite disks and its high visible-light photocatalytic performance

•Highly visible-light photocatalytic active nano sheets with β-Bi2O3-like phase structure have been composed onto diatomite disks by hydrothermal synthesis.•During hydrothermal process, the in-situ biomasses and their products on natural diatomite benefit the vertical growth of Bi2O3 nano sheets by changing the surface charges of diatomite carriers.•The chemical combination between β-Bi2O3-like phase and diatomite improves the formation process, thermal stability and photocatalytic activity of Bi2O3 nano sheets.•Three different pre-treating processes for in-situ biomasses of natural diatomite have been compared, hydrogen peroxide pretreatment narrows the band gap from 2.93 eV to 2.72 eV greatly, resulting in increased visible-light photocatalytic activity of Bi2O3/diatomite composite.