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• A new S-doped flower-like BiOI was synthesized via two-step hydrothermal-sulfuration method. • BiOI via engineering the surface oxygen vacancy and exposed {001} crystal planes. • S-BiOI exhibited enhanced photocatalytic Cr(VI) reduction activity. A facile strategy was proposed to fabricate the S-doped flower-like BiOI microspheres (S-BiOI) for boosting the photocatalytic performance of BiOI via engineering the surface oxygen vacancy and exposed {001} crystal planes. The S-doping generated oxygen vacancies in BiOI lattice structure to create point defects and exposed {001} crystal planes, resulting in a decrease in bandgap and an enhancement in charges separation, which could significantly hasten the photocatalytic reaction. The concentration of CH 4 N 2 S was a key factor to promote the Cr(VI) reduction activities. The optimized S-BiOI 1.25 presented a superior Cr(VI) removal efficiency of 100% for 60 min, which Cr(VI) reduction rate was 11.3 times higher than the pristine BiOI and still remained 97.5% Cr(VI) removal after 5 cycles. DFT calculation confirmed that the bandgap of the S-BiOI was narrowed compared to that of BiOI, but the S-BiOI still remained the intrinsic band structure of the pristine BiOI. [Display omitted]. [ABSTRACT FROM AUTHOR]

A novel three-dimensional (3D) network rodlike Ag2S/Bi2SiO5photocatalyst with a p–n heterostructure composed of ultrafine Ag2S nanoparticles (NPs) and Bi2SiO5nanosheets was prepared using an anionic self-regulation strategy by a two-step hydrothermal process. The architecture facilitated the efficient transfer and separation of photogenerated electron–hole pairs. The optimal Ag2S/Bi2SiO5composite (ABSO0.10) exhibited an excellent reduction activity (93.5% Cr(VI) removal in wastewater containing 50 mg·L–1Cr(VI) within 90 min under visible light), which was about 11.2 and 25.6 times higher than that of the pristine Ag2S and virgin Bi2SiO5, respectively. Assisted by experiments and density functional theory (DFT) calculations, a possible photocatalytic mechanism for Cr(VI) reduction over the Ag2S/Bi2SiO5composite under visible-light irradiation was proposed.