| Summary: | The electrocatalytic reduction of CO<sub>2</sub> into useful fuels, exploiting rationally designed, inexpensive, active, and selective catalysts, produced through easy, quick, and scalable routes, represents a promising approach to face today’s climate challenges and energy crisis. This work presents a facile strategy for the preparation of doped SnO<sub>2</sub> as an efficient electrocatalyst for the CO<sub>2</sub> reduction reaction to formic acid and carbon monoxide. Zn or Ti doping was introduced into a mesoporous SnO<sub>2</sub> matrix via wet impregnation and atomic layer deposition. It was found that doping of SnO<sub>2</sub> generates an increased amount of oxygen vacancies, which are believed to contribute to the CO<sub>2</sub> conversion efficiency, and among others, Zn wet impregnation resulted the most efficient process, as confirmed by X-ray photoelectron spectroscopy analysis. Electrochemical characterization and active surface area evaluation show an increase of availability of surface active sites. In particular, the introduction of Zn elemental doping results in enhanced performance for formic acid formation, in comparison to un-doped SnO<sub>2</sub> and other doped SnO<sub>2</sub> catalysts. At −0.99 V versus reversible hydrogen electrode, the total faradaic efficiency for CO<sub>2</sub> conversion reaches 80%, while the partial current density is 10.3 mA cm<sup>−2</sup>. These represent a 10% and a threefold increases for faradaic efficiency and current density, respectively, with respect to the reference un-doped sample. The enhancement of these characteristics relates to the improved charge transfer and conductivity with respect to bare SnO<sub>2</sub>.
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