Synergistic effect of surface coated and bulk doped carbon on enhancing photocatalytic CO2 reduction for MgIn2S4 microflowers.

• MgIn 2 S 4 , carbon-coated MgIn 2 S 4 , carbon coated and doped MgIn 2 S 4 , are synthesized. • MgIn 2 S 4 modified with carbon exhibits remarkably enhanced photocatalytic activity. • The function for doped carbon and coated carbon are investigated systematically. Convert inert CO 2 into chemical fuel via photocatalytic reduction is very intriguing. However, high charge recombination rate and inadequate CO 2 absorption severely impede photocatalytic CO 2 reduction activity. To address these drawbacks, we developed a strategy of MgIn 2 S 4 modification by carbon. Two types of photocatalysts with carbon modifications, carbon-coated MgIn 2 S 4 (MgIn 2 S 4 -SC); carbon coating and doping MgIn 2 S 4 (MgIn 2 S 4 -Cx), were obtained and exhibited significantly enhanced catalytic activity. The CO evolution rate of MgIn 2 S 4 -C2 and MgIn 2 S 4 -SC reached 19.5 and 7.03 times higher than that of unmodified MgIn 2 S 4 , respectively. Our experimental and theoretical results disclosed that doped carbon for MgIn 2 S 4 could prevent charge recombination in the bulk, facilitate CO 2 adsorption, and decrease photocatalytic reaction energy barrier, while coated carbon could accelerate surface carrier migration, but had smaller and greater effect on fascinating CO 2 adsorption and decreasing reaction energy barrier. The synergistic effect of surface coated and bulk doped carbon could maximize the photocatalysis efficiency. [ABSTRACT FROM AUTHOR]