Pd/SiO₂ Catalysts Prepared via a Dielectric Barrier Discharge Hydrogen Plasma with Improved Performance for Low-Temperature Catalytic Combustion of Toluene

Abstract

Catalytic combustion is a hot topic both in academic research and in environmental protection. In this work, novel SiO 2 -supported Pd catalysts (Pd/SiO 2 -P) were prepared by hydrogen plasma and used in the catalytic combustion of toluene. Characterization results indicated that H 2 -plasma treatment could significantly enhance the dispersion of Pd nanoparticles and increase the proportion of Pd 0 . Meanwhile, H 2plasma treatment also enlarged the pore size of the SiO 2 carrier compared with that of the traditional high-temperature calcination and reduction technology. As a result, Pd/ SiO 2 -P showed higher catalytic activity and stability than the traditional Pd/SiO 2 -R catalyst. Under harsh working conditions [with 1000 ppm toluene in feed and 60,000 mL/(g h)], the T 98 of toluene over 0.5% Pd/SiO 2 -P decreased obviously from 200 °C (over 0.5% Pd/SiO 2 -R) to 170 °C. This work could provide a novel method for the preparation of supported noble-metal catalysts.

Close-Contact Oxygen Vacancies Synthesized by FSP Promote the Supplement of Active Oxygen Species To Improve the Catalytic Combustion Performance of Toluene

“…Recently, numerous works have reported the excellent performance of palladium (Pd) in the low-temperature catalytic combustion of toluene. The performance of Pd is mainly affected by the valence state, − and metal Pd is more advantageous in VOC oxidation . At the same time, the particle size and dispersion of Pd also have a great influence on the performance of the catalyst.…”

Synthesis of Highly Dispersed Palladium Nanoparticles Supported on Silica for Catalytic Combustion of Methane

“…Palladium supported on silica (Pd/SiO 2 ) has been widely used as the catalyst in chemical and pharmaceutical production, and environmental protection, such as in Suzuki coupling reactions, , selective hydrogenation of hydrocarbons, , selective oxidation of alcohols and hydrocarbons, − and catalytic combustion of VOCs. , The catalytic performance of Pd/SiO 2 catalysts often showed an obvious dependence on the Pd size in these reactions. Thus, a subtle control of the size of Pd nanoparticles and their distribution is of great importance for Pd/SiO 2 catalysts.…”

“…Thus, a subtle control of the size of Pd nanoparticles and their distribution is of great importance for Pd/SiO 2 catalysts. While many methods were developed to prepare highly dispersed and well size-distributed Pd/SiO 2 catalysts, − the SEA and CEDI methods were identified as the simplest and lowest-cost methods. ,,, Regalbuto et al prepared highly dispersed Pd/SiO 2 catalysts (Pd loading: 1.1–2.2 wt %, reduction at 200 °C) by the SEA method using [Pd­(NH 3 ) 4 ] 2+ as the Pd precursor in high-pH conditions (ca. 12) .…”

“…Herein, a series of Pd/SiO 2 samples were prepared by WI, DI, SEA, and CEDI methods, which were reduced at 600 °C in order to investigate the thermal stability of the Pd nanoparticles at higher temperatures, as many Pd-catalyzed reactions were usually conducted at temperatures much higher than 200 °C. − Pd/SiO 2 samples with highly dispersed and narrow size-distributed palladium nanoparticles (1–2 nm) could be obtained via the SEA method. We further refined the SEA method by regulating the surface loadings (surface area of SiO 2 support per liter of impregnating solution, SL) or alkali/SiO 2 to efficiently deprotonate the hydroxyls on SiO 2 and reduce the losses of the Pd metal and SiO 2 support.…”

Toward the Mechanism Study of Pd/γ-Al2O3-Assisted Bioalcohol Combustion in a Flow Reactor

“…A recent review illustrates the progress on the design of Pd-based catalysts applied in reactions of selective hydrogenation, CO oxidation, methane combustion, electrocatalytic energy conversion (HER, ORR, and MOR), CO 2 reduction, and H 2 production. Specifically, Pd-based catalysts have been extensively studied in the catalytic removal of VOCs, including alkanes, alkenes, aromatics, and oxygen-containing and chlorinated compounds, in recent years. − For the catalytic combustion of ethanol over Pd-based catalysts, it was found that most of the current research focuses on the enhancement of catalytic performance by modification under lean conditions. − Furthermore, studies related to the mechanism are generally involved in several models that have been proposed for complete catalytic combustion . The detailed reaction pathways and intermediate descriptions of the reaction mechanism are still unclear and play an important role in the study of catalytic combustion.…”