Nickel electrocatalysts for one-step synthesis of long hydrocarbons from CO2

A collaboration supported by NCCR Catalysis between the groups of Profs. J. Pérez-Ramírez at ETH Zurich, B.S. Yeo at the National University of Singapore (NUS), and N. López at the Institute of Chemical Research of Catalonia (ICIQ) has led to the discovery of a new family of materials able to transform electrocatalytically carbon dioxide into long hydrocarbons at room temperature and pressure. After four decades of intense research efforts, no more than three carbon dioxide molecules could be coupled in a single step at appreciable rates over electrocatalysts based exclusively on copper. The products obtained were ethylene, ethanol and propanol. In contrast, the new family of nickel-based catalysts can couple up to six CO₂, giving direct access now to a richer pool of products, with selectivities to linear and branched hydrocarbons of 16% and up to 7% to C₃-C₆ products. These breakthrough results have been recently published in Nature Catalysis.

The formation of long carbon products was detected during a search for alternative catalysts to copper. Metallic nickel is typically a poor CO₂ reduction catalyst because it adsorbs carbon monoxide, a key intermediate in the reaction, too strongly, stopping the reaction. However, using inorganic nickel oxygenates such as nickel phosphate or carbonate, the team could identify up to 28 different products. Extensive experimental and computational efforts managed to identify the key to the unique performance: the ability to keep a few nickel-oxygen bonds in the electrode during the reaction. This generates polarized nickel atoms (Ni^d+) that only weakly adsorb carbon monoxide, enabling the coupling of carbon species. These results encourage further research towards the implementation of Ni-based technologies in the future. The team is already working to exploit the new research avenue these catalysts open, as they think we may have only scratched their potential. More information available in https://doi.org/10.1038/s41929-022-00803-5.

Image credit:
Javier Pérez-Ramírez

Publication details:
Long-chain hydrocarbons via CO₂ electroreduction enabled by polarized nickel catalysts
Y. Zhou, A.J. Martín, F. Dattila, S. Xi, N. López, J. Pérez-Ramírez, B.S. Yeo
Nat. Catal. 2022, in press (doi:10.1038/s41929-022-00803-5)