S2- doping inducing self-adapting dual anion defects in ZnSn(OH)6 for highly efficient photoactivity

The S2- doping and oxygen vacancies (OVs) co-modified ZnSn(OH)6 (ZHS) were fabricated by the microwave method. Due to the synergistic effects of S2- doping and OVs in ZHS, the removal rates of toluene and nitric oxide reached 92.5 % and 49.8 %, respectively. Experimental and theoretical results (DFT) show that the improved photoactivity can stem from: 1) the alteration of O 2p band center position. S2- doping causes the O 2p band center to shift upward relative to the Fermi level, reducing the formation energy of OVs; 2) the change of the local electron distribution. A rapid charge transfer channel was formed between S2- and adjacent OVs; 3) abundant active sites. The activation of small molecules on the photocatalyst surface were promoted and produced rich active free radicals. Thus, the construction of dual anion defects modified photocatalyst offers a simple strategy for the design of highly efficient photocatalyst for air pollution control.