Chlorine in NiO promotes electroreduction of CO2 to formate
We report the exceptional finding that NiO, a known electroactive catalyst for the reduction of CO2 to CO, can be tuned to become an active electrocatalyst for CO2 reduction to formate when chlorine is synthetically incorporated into NiO. The CO2 reduction reaction (CO2RR) is carried out on chlorine-containing NiO octahedral particles made by a solid-state synthesis method yielding a Faradaic efficiency (FE) of 70 % for formate production at -0.8 V vs. RHE with a partial current density of 14.7 mA/cm2. XPS confirms the presence of Ni3+ and Ni2+ species, indicating the existence of uncoordinated Ni. The Ni3+/Ni2+ ratio increases with the Cl concentrations on NiO. Cl concentrations are also confirmed with STEM-EDX. DFT modeling provides insights into the thermodynamic stability and CO2RR mechanism over the Cl-containing NiO surface. It is suggested that Cl can occupy the defective sites created by oxygen vacancies on the NiO model with Cl (O-alpha+Cl). The surface Pourbaix diagrams constructed from DFT indicate the preferred surface terminations favorable at the operating conditions for the CO2RR, which closely agrees with the experimental findings. The O-alpha+Cl has been found to promote CO2RR to formate. Our results create new possibilities in the development of earth-abundant electrocatalysts for selective CO2RR.
Chemical Reaction Engineering by Additive Manufacturing of Mesoscale MetaMaterials
European Research CouncilFind out more...
PublicationApplied Materials Today, 2022, 28, 101528
Other Funding informationWe also thank DGAPA-UNAM projects IN105722, IA100920, IN110820 and CONACyT grant A1-S-9070, for partial financial support. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, projects LANCAD-UNAM-DGTIC-051, LANCAD-UNAM-DGTIC-368 and LANCAD-UNAM-DGTIC-150. R.P.P. acknowledges CONACyT for the postdoctoral position. F.R.-Z would like to acknowledge the Slovenian Research Agency program P2-0393. R.L. and M.V. acknowledge the Irish Centre for High-End Computing (ICHEC) for the computational facilities and support.
Also affiliated with
- Bernal Institute
Department or School
- Chemical Sciences