Synergistic effect between amino functional group and graphene oxide in selective photocatalytic CO2 reduction to formic acid

Carbon dioxide (CO2) reduction to useful possible chemicals is of great significance to energy supply, while formic acid is one of the most desirable product among the many other chemicals. In this study, a novel reduced graphene oxide (rGO) coupled doped TiO2 with NH2-MIL-125(Ti)(TiM) composite photocatalysts TiO2@rGO@TiM was designed by using a solvent-thermal method to facilitate the photocatalytic CO2 reduction to formic acid under the visible light. Benefiting from the special structure of TiO2@rGO@TiM, up to a rate of 113 mu mol center dot g- 1 center dot h- 1 of formic acid was produced in a photochemical process, which is four times greater than that of pure TiO2 and TiM without any sacrificial agent. The results of structure and photoelectrochemical characterization demonstrated that the enhanced production of formic acid was attributable to the synergistic effect generated by the incorporation of the amino functional group and reduced graphene oxide, resulting in the effective photo-induced carrier spatial segregation and transfer and improving the catalytic activity.