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 Niδ+ 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 Niδ+ 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.