The Role of Nitrogen on Industrially Important ZnO/Cu Catalysts for Conversion of CO2 to Methanol

ZnO/Cu/Al2O3 catalysts are used in industrial applications to produce methanol from CO2 gas. Because of the high barriers and also of the poor interaction between CO2 and the catalysts, current methods require extreme conditions, thereby significantly increasing production costs. In the search for more efficient catalysts based on the ZnO/Cu/Al2O3 system, this work investigates CO2 adsorption, activation, and hydrogenation on N-doped ZnO clusters supported on Cu(111). Our results show that N-doping significantly enhances CO2 adsorption compared to pure ZnO/Cu. Even in a hydrogen-rich environment, N-doped ZnO/Cu systems show a dramatically higher CO2 adsorption energy than the undoped ZnO/Cu configuration, sufficient to counterbalance the gas-phase entropic penalty in a wide range of conditions. In addition to enhancing CO2 adsorption, the overall reaction barrier to CO2 reduction is significantly reduced, enabling methanol production through a reverse water-gas shift (RWGS) pathway. These findings demonstrate that N-doping of ZnO/Cu catalysts can enhance CO2 adsorption and activation, thereby facilitating methanol synthesis under less demanding reaction conditions.