Enhancement of catalytic performance in Zr0.1Ce0.9O2-δ through transition metal doping and exsolution

Abstract

As a cost-effective alternative to noble material, Zr_0.1Ce_0.9O_2-δ (ZDC) plays a crucial role in industrial catalysis, including applications such as automotive exhaust treatment, solid oxide fuel cells, and the catalytic combustion of hydrocarbons, due to its excellent oxygen storage capacity, high thermal stability, and resistance to carbon deposition. An important new approach for optimizing the performance of Zr_0.1Ce_0.9O_2-δ as a catalyst is the in-situ exsolution of metal nanoparticles. Exsolution is recognized as a promising strategy for generating highly dispersed nanoparticles on the catalyst support, enhancing catalytic activity and stability. Herein, transition metal cations (Fe, Co, Ni and Cu ions) are doped into the ZDC fluorite-structured oxides (ZDCM) and exsolved on its surface under reduction conditions (ZDCM-R, M = Fe, Co, Ni and Cu). X-ray photoelectron spectroscopy and Raman spectroscopy confirm that the exsolution of Co and Cu generated an oxygen-vacancy-rich layer on the support surface, which significantly enhanced their catalytic performance. As a result, both ZDCCu-R and ZDCCo-R catalysts were able to achieve complete CO oxidation at temperatures below 200 °C. Moreover, ZDCCo-based anodes have shown a maximum power density of 348.2 mW at 800 °C and demonstrated exceptional stability during direct methane utilization in solid oxide fuel cells.