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 C₂ or C₃ molecules. Herein, we disclose that inorganic nickel oxygenate-derived electrocatalysts can generate linear and branched C₃ to C₆ 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^δ+ active sites associated with Ni–O bonds, which bind CO moderately. The reduction of selected C₁ molecules and density functional theory simulations suggest that the Ni^δ+ sites promote a mechanism reminiscent of the Fischer–Tropsch synthesis: COOH + CH_x coupling followed by successive CH_x 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.