Electrochemical reduction of CO2 on single-atom catalysts anchored on N-terminated TiN (111): Low overpotential and high selectivity

The ever-increasing concentration of carbon dioxide (CO2) in atmosphere has been resulting in disastrous effect on the nature and environment. Among the various methods for the CO2 reduction, the electrochemical reduction of CO2 (e-CO2RR) into fuels is considered to be much more effective. In this work, we find that the single atom catalysts (SACs) (SACs = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) can be firmly anchored on the N-terminated TiN (1 1 1) surface because of high binding energies on the basis of density-functional theory calculations. We show that the SACs on the N-terminate of TiN(1 1 1) can greatly reduce the energy barrier for e-CO2RR and improve the selectivity of products. SACs, including Sc, Ti, and V, show a high catalytic performance to produce CH4 with a low limiting potential of 0.68, 0.22, and 0.48 eV, respectively. Both CH(4 )and CH2O can be obtained on SAC-Ni with the potential-determining step (PDS) of 0.77 eV. SAC-Cu can produce CH4 and CH3OH. Our findings demonstrate that N-terminated surface is suitable for anchoring SACs and the catalytic performance for e-CO2RR, such as overpotential and selectivity, can be optimized by using different transition metals, which provides a great way for the convertion CO(2 )into fuels.