Long-chain hydrocarbons by CO2 electroreduction using polarized nickel catalysts

The electroreduction of CO2, driven by renewable electricity, can be used to sustainably generate synthetic fuels. So far, only copper-based materials have been used to catalyse the formation of multicarbon products, albeit limited to C-2 or C-3 molecules. Herein, we disclose that inorganic nickel oxygenate-derived electrocatalysts can generate linear and branched C-3 to C-6 hydrocarbons with sustained Faradaic efficiencies of up to 6.5%, contrasting with metallic nickel, which is practically inactive. Operando X-ray absorption spectroscopy, electrochemical CO stripping and density functional theory pinpoint the presence of stable, polarized Ni delta+ active sites associated with Ni-O bonds, which bind CO moderately. The reduction of selected C-1 molecules and density functional theory simulations suggest that the Ni delta+ sites promote a mechanism reminiscent of the Fischer-Tropsch synthesis: COOH + CHx coupling followed by successive CHx insertions. Our results disclose atom polarization to be the key that prevents the CO poisoning of nickel and enables CO2 reduction to a wider pool of valuable products.

Automated summary

Scientists have discovered that using inorganic nickel oxygenate-derived electrocatalysts can efficiently convert CO2 into C-3 to C-6 hydrocarbons, with a Faradaic efficiency of up to 6.5%. This is in contrast to metallic nickel, which shows little to no activity. The study reveals that atom polarization is key in preventing nickel poisoning and enabling the reduction of CO2 into valuable products.