Exploring dopant effects in stannic oxide nanoparticles for CO2 electro-reduction to formate
Young‐Jin Ko, Jun-Yong Kim, Woong Hee Lee, Min Gyu Kim, Tae‐Yeon Seong, Jongkil Park, YeonJoo Jeong, Byoung Koun Min, Wook‐Seong Lee, Dong Ki Lee, Hyung‐Suk Oh
Abstract
Abstract The electrosynthesis of formate from CO 2 can mitigate environmental issues while providing an economically valuable product. Although stannic oxide is a good catalytic material for formate production, a metallic phase is formed under high reduction overpotentials, reducing its activity. Here, using a fluorine-doped tin oxide catalyst, a high Faradaic efficiency for formate (95% at 100 mA cm −2 ) and a maximum partial current density of 330 mA cm −2 (at 400 mA cm −2 ) is achieved for the electroreduction of CO 2 . Furthermore, the formate selectivity (≈90%) is nearly constant over 7 days of operation at a current density of 100 mA cm −2 . In-situ/operando spectroscopies reveal that the fluorine dopant plays a critical role in maintaining the high oxidation state of Sn, leading to enhanced durability at high current densities. First-principle calculation also suggests that the fluorine-doped tin oxide surface could provide a thermodynamically stable environment to form HCOO* intermediate than tin oxide surface. These findings suggest a simple and efficient approach for designing active and durable electrocatalysts for the electrosynthesis of formate from CO 2 .