Ce Promotion of In 2 O 3 for Electrochemical Reduction of CO 2 to Formate

• Published in: ACS catalysis 2024-11, Vol.14 (22), p.16589-16604
• Main Authors: Wissink, Tim, Rollier, Floriane A, Muravev, Valery, Heinrichs, Jason M J J, van de Poll, Rim C J, Zhu, Jiadong, Anastasiadou, Dimitra, Kosinov, Nikolay, Figueiredo, Marta C, Hensen, Emiel J M
• Format: Article
• Language: English
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.4c02619

In O is a promising electrocatalyst for CO electroreduction (CO ER) to formate. In O nanoparticles doped with Pd, Ni, Co, Zr, and Ce promoters using flame-spray pyrolysis were characterized and evaluated in a gas diffusion electrode for the CO ER. Doping results in slight shifts of the In binding energy as probed by XPS, which correlates with a change of the Faradaic efficiency to formate (FE ) in the order Ce-doped In O > Zr-doped In O > In O > Pd-doped In O > Ni-doped In O > Co-doped In O . However, the differences in CO ER performance are caused mainly by the different extent of In O reduction. Co-doped In O is prone to complete reduction to a stable Co-In alloy with a low FE due to a high hydrogen evolution activity. The stabilizing effect of Ce on In O is further demonstrated by an X-ray absorption spectroscopy study of a set of Ce-doped In O samples (10, 50, 90 at%), highlighting that reduction of In O is suppressed with increasing Ce content. Optimum performance in terms of FE is obtained at a Ce content of 10 at%, which is attributed to the stabilization of In O under negative bias up to -2 V. At higher Ce content, less active CeO is formed. The highest FE of 86% observed for In O doped with 10 at% Ce, at a current density of 150 mA/cm , compares favorably with a FE of 78% for In O .