Surface Modification by Amino Group Inducing for Highly Efficient Catalytic Oxidation of Toluene over a Pd/KIT-6 Catalyst

Abstract

Toluene is one of the typical volatile organic compounds in industry, particularly in energy and fuels production processes, which is required to be eliminated effectively to protect the environment. Catalytic oxidation of toluene is widely studied for its high efficiency, and rational design and synthesis of metal catalysts are keys for toluene oxidation. In this study, an efficient catalyst was designed and synthesized by introducing −NH 2 groups on the ordered mesoporous silica (KIT-6) surface to anchor and disperse Pd species, leading to Pd nanoparticles being highly dispersed with uniform particle size distribution. Meanwhile, it was found that the introduction of −NH 2 made Pd centers present an electron-rich state, and the active Pd centers could activate O 2 molecules to generate more reactive oxygen species and promote the conversion of toluene, which was verified by in situ XPS and O 2 -TPD characterization. Compared with the catalysts prepared by an impregnation method, the catalytic performance of the Pd/ NH 2 -KIT-6 (0.5 wt %) catalyst was significantly improved. A conversion of 90% for toluene (2400 ppm, 24,000 mL•g −1 •h −1 ) was achieved at 171 °C, and the toluene conversion was maintained above 90% for 900 min, displaying the excellent activity and stability of the Pd/NH 2 -KIT-6 catalyst.

Palladium–Tin Alloy Nanoparticles in Different Crystalline Phases for Direct Hydrogen Peroxide Synthesis

“…This partially accounts for the high H 2 O 2 productivity. The O 2 -TPD results on Pd–Sn/TiO 2 catalysts demonstrate that the desorption peaks at the low temperature (∼115.6 °C) are attributed to the desorption of O 2 molecules and those at the high temperature (∼409.7 °C) are assigned to the desorption of O species (O*) formed by O 2 dissociation . The peak areas of the desorption of O 2 on the three catalysts are similar, but the peak area of the desorption of O* on Pd 3 Sn 2 /TiO 2 is significantly lower than that of the other two, indicating that Pd 3 Sn 2 can effectively inhibit the dissociation of O–O (Figure b).…”

Highly dispersed Pd nanoparticles on a SiO2 support for dehydrogenation of dodecahydro-N-ethylcarbazole

“…These results indicate that Pd 0 in the 0.3% Pd–NH 2 (1) catalyst shows an electron-rich state. 41 The dehydrogenation mechanism of 12H-NECZ is the C–H activation, 42 which requires the activation of C–H by electron-rich Pd 0 electrons. In this respect, the electron-rich state of Pd–NH 2 catalysts could facilitate the dehydrogenation of 12H-NECZ and accelerate the reaction process.…”

Efficient aqueous-phase hydrogenation of m-xylylenediamine to 1,3-cyclohexandimethylamine over a highly active and stable ruthenium catalyst

“…It was reported that grafting alkylamine on a support by silylation could immobilize the transition metal via the coordination of the transition metal ion and –NH 2 group, which would improve metal dispersion, modify its electronic property, and improve its stability due to strong metal–support interaction. Cui 28 synthesized the Pd/NH 2 -KIT-6 catalyst by introducing –NH 2 groups on the ordered mesoporous silica (KIT-6) surface for anchoring Pd species, leading to the formation of highly dispersed Pd nanoparticles with uniform particle size distribution. It was found that compared with the catalysts prepared by impregnation method, the catalytic performance of the Pd/NH 2 -KIT-6 catalyst for the conversion of toluene was significantly improved.…”