Theoretical study on CO production mechanism from CO2 reduction on Cu–catalyst surface with different oxidation states.

[Display omitted] • CO 2 reduction to CO on Cu(1 1 1), CuO(1 1 1) and Cu 2 O(1 1 1) surfaces is studied by DFT. • The favored pathway for CO 2 reduction to CO in three Cu-based catalysts is determined. • Cu 2 O(1 1 1) exhibits the best catalytic activity among the three catalysts. The rational design of copper (Cu)-based catalysts with different oxidation states is essential to achieve highly selective and efficient CO 2 electroreduction. However, the effect of different oxide states of Cu-based catalysts has rarely been studied. Herein, the reaction mechanism of CO 2 hydrogenation into CO on Cu-based catalysts with different oxidation states, such as Cu(1 1 1), Cu 2 O(1 1 1) and CuO(1 1 1), was studied using the density functional theory. The most favored pathway for CO production and the rate-controlling step on the three catalyst models were determined. The results show that, Cu 2 O (1 1 1) shows the best catalytic activity among the three catalysts due to the lowest activation barrier. The electronic structure analysis shows that Cu 2 O has the proper electronic structure to activate CO 2 which is further reduced to CO. This work provides an important insight on the effect of oxidation state of Cu-based catalysts on the reduction of CO 2 to CO. [ABSTRACT FROM AUTHOR]