Photocatalytic reduction of CO2 into CO over nanostructure Bi2S3 quantum dots/g-C3N4 composites with Z-scheme mechanism

Bi2S3 quantum dots (QDs) /g-C3N4 composites with various Bi2S3 QDs contents were synthesized by hydrothermal reaction method and used in CO2 photocatalytic reduction, which demonstrated much higher photocatalytic activity than pristine g-C3N4. Experimental results indicated that the 20 wt% Bi2S3 QDs/g-C3N4 showed a remarkable photocatalytic activity, which was 4 times the CO yield of that pure g-C3N4. The SEM and TEM results indicated that Bi2S3 QDs had uniformly covered the catalysts surface, which could effectively increase the absorption of visible-light and promote the separation of photogenerated carriers, thereby decrease the recombination rate of photogenerated electron-hole pairs and enhance the performance of photocatalytic reduction.