Construction of Pd-Modified NiCoO<i><sub>x</sub></i> Hollow Nanospheres with Surface Hydroxyls and Oxygen Vacancies for Highly Enhanced Catalytic Toluene Oxidation Activity
Jiafu Qu, Dongyun Chen, Najun Li, Qingfeng Xu, Hua Li, Jinghui He, Jianmei Lu
Abstract
The catalytic activity of well-designed hollow spinel NiCoOx catalysts synthesized using a facile hard template method was investigated. These materials demonstrated higher performance during toluene oxidation compared with NiO, Co3O4, and NiCoOx nanosheets with 100% conversion at 250 °C. Hollow NiCoOx nanospheres (h-NiCoOx) were found to have numerous surface hydroxyl groups and large surface areas together with oxygen vacancies, all of which promoted the oxidation reaction. Varying amounts of Pd were loaded on h-NiCoOx and the catalytic efficiency was further improved. A 2.0 wt % Pd/h-NiCoOx sample exhibited the highest activity, achieving approximately 100% toluene conversion at 190 °C with a lower activation energy of 41.9 kJ mol–1 compared with the pristine h-NiCoOx (95.6 kJ mol–1). These results demonstrate that such materials have potential applications in the mitigation of toluene pollution.