Boosting sulfur tolerance and catalytic performance in toluene combustion via Enhanced-mechanism of Ce-Fe dopants incorporation of LaCoO3 perovskite

Abstract

In-depth mechanism of catalytic reaction could help to guide the development of efficient catalysts with high tolerance to sulfur. Here, to seek optimized dopants to improve both sulfur tolerance and activity of Co-based perovskite catalysts for the removal of volatile organic compounds (VOCs), a series of La1−xCexCo1−yFeyO3 perovskites were prepared and then tested for toluene combustion before and after SO2 poisoning. Results showed that both sulfur tolerance and catalytic activity could be improved by adding Ce and/or Fe dopants with a suitable ratio, in which Ce dopant has advantages in catalytic activity, while Fe dopant is better for sulfur tolerance. Multiple in-situ and ex-situ characterization analysis indicated that dopants can alter the oxidation state of B-site, reducibility and oxygen vacancy content to varying degrees, thus increasing the catalytic activity. In addition, the ceria generated by Ce dopants could limits the sulfurization of the main active phase, Fe dopants would lead to highly stable and SO2-insensitive perovskite lattices, while co-doping of Ce and Fe elements could interact to form Ce-Fe solid solution and making the formed sulfate more mobile and decomposable after heating. This study presents a catalytic reaction enhanced-mechanism to provide theoretical basis and novel insights for the application of perovskite catalysts.