Enhanced catalytic hydrogenation reduction of bromate on Pd catalyst supported on CeO2 modified SBA-15 prepared by strong electrostatic adsorption

摘要

Supported Pd catalysts on CeO2 modified SBA-15 (Ge-SBA-15) were prepared using the strong electrostatic adsorption (SEA) method. For comparison, supported Pd catalysts on SBA-15 and Ce-SBA-15 were prepared using the impregnation method. Liquid-phase catalytic hydrogenation of bromate was investigated on those catalysts. The catalysts were characterized by X-ray diffraction, N-2 adsorption-desorption, measurement of the point of zero charge (PZC), transmission electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy - energy dispersive spectroscopy, and H-2 chemisorption. Characterization results showed that CeO2 modification resulted in increased PZC of SBA-15 from 2.7 to 4.8. For Pd/Ce-SBA-15 catalysts prepared using the SEA method, Pd particles were site-specifically deposited on CeO2 moieties. As a result, much higher Pd dispersion and stronger metal-support interaction were observed as compared with the catalysts prepared using the impregnation method. Furthermore, increasing CeO2 modification amount and decreasing Pd loading amount effectively enhanced Pd dispersion and metal-support interaction. For the catalytic reduction of bromate, Pd/SBA-15 prepared using the impregnation method exhibited negligible catalytic activity. In contrast, markedly enhanced catalytic activities were observed on Pd catalysts supported on Ce-SBA-15. Additionally, Pd/Ce-SBA-15 prepared using the SEA method displayed much higher activity than that prepared using the impregnation method. For Pd/Ce-SBA-15 prepared using the SEA method, increasing CeO2 modification amount led to enhanced catalytic activity. The present findings clearly indicate that Pd/Ce-SBA-15 prepared by the SEA method can be used as a promising catalyst in liquid phase catalytic hydrogenation of disinfection byproducts.