A Unique Amorphous Porous BiSbOx Nanotube with Abundant Unsaturated Sb-Stabilized BiO8−x Sites for Efficient CO2 Electroreduction in a Wide Potential Window

The CO 2 electroreduction reaction using sustainable electricity emerges as a viable strategy to produce high-value-added and profitable chemicals. The achievement of superior activity at a lower overpotential and higher selectivity in a wide potential window is vitally important for large-scale industrial applications. Herein, a carbon-composite amorphous porous BiSbO x nanotube with abundant unsaturated sites is reported to boost the conversion of CO 2 to formate, exhibiting a formate selectivity of >90% in an extremely broad range of potentials from −0.5 to −1.4 V versus reversible hydrogen electrode (RHE) and a maximal energy conversion efficiency of 77.1%. Importantly, pure formic acid solution is directly obtained in a solid-electrolyte cell for industrial-scale applications. The porous tubular structure can expose more catalytic active sites, accelerate the mass transfer, and show fast surface charge transfer. Moreover, the unique coordination-unsaturated Sb-stabilized BiO 8−x site can not only enhance the adsorption and activation of CO 2 but also reasonably balance the stabilization and hydrogenation of *OCHO intermediate, thus leading to its obviously higher catalytic performance. As a result, a novel amorphous porous BiSbO x nanotube is successfully designed for efficient CO 2 electroreduction, which may shed new light on developing many more amorphous composite metal oxide catalysts for conversion of inert small molecules.