Snowflake-like In2S3/Cu2S heterojunction for simultaneous photocatalytic persulfate oxidation of tetracycline hydrochloride and CO2 photoreduction

To achieve tetracycline hydrochloride (TCH) elimination and CO2 photoconversion to CH4 and CO, snowflakelike In2S3/Cu2S heterojunctions were fabricated through the hydrothermal approach. Z-scheme junction generated between In2S3 and Cu2S was likely to separate and migrate the photoactivated e-/h+ pairs, boosting the photocatalytic-persulfate (photo-PS) activity and CO2 photoconversion capacity. The single photo-PS oxidation of TCH and CO2 photoreduction as well as their simultaneous photocatalytic behaviors over snowflake-like In2S3/Cu2S composites were comparatively investigated. For optimal 3-In2S3/Cu2S with a nominal In2S3 content of 5.0 wt%, the removal efficiency of unary photo-PS oxidation system was 99.90 %, CH4 and CO yield rates of single CO2 photoreduction process were respectively 177.67 and 94.42 mu mol g-1h- 1. In dual photo-PS oxidation and CO2 photoreduction system, the addition of CO2 leaded to the lower photo-PS activity, while the higher CH4 and CO yield rates of 3-In2S3/Cu2S. When added CO2 to dual photocatalytic system, the removal efficiency of TCH, CH4 and CO yield rates reached to 78.38 %, 106.80, and 73.84 mu mol g-1h- 1, which were 0.94, 1.34, and 1.39 folds than those without CO2. This work provided the possibility of simultaneous photo-PS oxidation of pollutants and CO2 photoconversion to C1 compounds.