Enhancing the intrinsic properties of flower-like BiOI by S-doping toward excellent photocatalytic performances

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 CH4N2S was a key factor to promote the Cr(VI) reduction activities. The optimized S-BiOI1.25 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.