Boosting lattice oxygen activity and accelerating intermediate consumption for enhanced toluene catalytic oxidation via CeCu solid solution engineering

Abstract

Background Ce-based catalysts demonstrated outstanding catalytic activity for volatile organic compounds (VOCs) oxidation. Cu had been extensively utilized as a secondary metal modifier to regulated the physicochemical properties of Ce-based catalysts, thereby enhancing toluene oxidation activity through facilitated lattice oxygen activation and accelerated intermediates consumption. Methods A series of CeCu catalysts were prepared employing the same Ce/Cu molar ratio (Ce/Cu = 4/1) but different preparation methods (co-precipitation, impregnation and sol-gel methods) to modulated CeCu solid solutions. Significant findings CeCu-CP, synthesized via co-precipitation, demonstrated superior catalytic activity (T 90 = 204 °C, GHSV = 21,000 h –1 ), surpassing counterpart catalysts by 10–30 °C. The homogeneous CeCu solid solution formation attenuated CeO 2 crystallinity, expanded specific surface area (101 m 2 /g) and diminished crystallite dimensions (6.75 nm), which collectively generating abundant active sites for toluene oxidation. Concomitantly, strengthened CeCu interaction promoted oxygen vacancy formation, enhanced low-temperature reduction capability, and activated lattice oxygen species. In situ DRIFTS analysis corroborated accelerated toluene to benzoic acid conversion over CeCu-CP, attesting to its outstanding catalytic efficiency. These findings establish a rational design strategy for boosting low-temperature VOCs oxidation activity in non-noble metal bimetallic systems.