Sn⁴⁺ doping enhanced inner electric field for photocatalytic performance promotion of BiOCl based nanoflowers

BiOCl powders with different amounts of Sn doping (0, 5%, 10%, 20% versus molar amount of Bi, denoting as BOC, BOC-S5, BOC-S10, BOC-S20 respectively) were prepared by solvothermal method. Sn doping resultant effect on obtained samples and their photocatalytic performance were studied. All Sn doped BiOCl showed stronger photocatalytic degradation ability towards organic dye RhB compared with undoped one, where BOCS10 with highest performance behaved 33% higher RhB degradation than BOC. Through relevant experiments and calculations, it's found that Sn doping stimulated more dispersive electron localization in [Bi2O2]2+ layer, favorable for carrier generation, while introduction of Sn4+ also strengthened the inner polarization along [001] direction, which improved intrinsic inner electric field revulsive carrier separation. Changes on electronic structure promoted carrier generation and transfer, providing higher photocatalytic performance. Photocatalytic reduction of CO2 manifested that Sn doped samples also behaved larger potential on synthesizing CH4 through CO2 reduction and BOC-S10 still exhibited highest performance with CH4 yield 67% higher than BOC. All the results manifested that Sn doping introduced transformation beneficial to promote photocatalytic performance.