Rapidly increasing anthropogenic carbon dioxide (CO_{2}) emissions, coupled with irreversible climate change and depleting fossil fuel reserves, have significantly increased the drive for CO_{2} utilisation. Iron sulfide as a catalyst for the hydrogenation of CO_{2} has been discussed in the literature for decades, especially in an origin-of-life context, but little experimental evidence exists in the literature for its feasibility. Here we report the catalytic properties of pyrrhotite (Fe_{1−x}S) for the hydrogenation of CO_{2} into formate. Advanced material characterisation methods in combination with computational studies have allowed us to identify surface S–Fe–O moieties as active sites for the reaction
