▎ 摘　　要

Herein electrolytic reduction of CO2 on transition metal decorated graphene quantum dot (M@GQD) has been investigated by using first-principles calculations. Comparative study of geometrical properties and charge distribution of CO2 adsorbed M@GQD revealed that while GQD is unable to activate CO2, the transition metal decorated sites of M@GQD are available for CO2 adsorption, activation and dissociation. Charge distribution and molecular orbital analysis indicate that metal centre on GQD act as a Lewis base and the overall activation process is guided by the transfer of electron density from the corresponding metal centre to the pi* orbital of CO2. The extent of CO2 activation is also analysed by the projected density of states (PDOS) which demonstrates that among the transition metal series Ti sites are available for CO2 activation and dissociation while activation does not occur involving Cu and Zn, due to their poor adsorption energy and lowest coupling of valence band state with the GQD. Overall transition metal decorated GQD opens up unlimited possibilities for designing new and highly selective and efficient catalysts for electrolytic CO2 reduction.