CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

Double graphitic-N doping for enhanced catalytic oxidation activity of carbocatalysts

Graphitic N (GrN) doping is an effective way to promote the catalytic oxidation activities of pristine graphene, but a low doping density still limits its practical use. Based on DFT calculations, a double graphitic N (GrN) doping method is proposed. When the two GrN atoms are located at two different but nearby hexatomic rings, the dissociation of O2 molecules is significantly facilitated and the subsequently formed oxygen groups remain active for SO2 oxidation. In contrast, if the two GrN atoms are located at the same hexatomic rings of graphene, sluggish carbonyl groups will be formed in spite of the dissociation of O2 molecules being extraordinarily preferred.

TiO2-nanosheet-assembled microspheres as Pd-catalyst support for highly-stable low-temperature CO oxidation

The Pd-embedded-in-TiO₂ structure could improve the activity and stability of the Pd/TiO₂ catalyst.

Theoretical study on geometric, electronic and catalytic performances of Fe dopant pairs in graphene

The formation geometries, electronic structures and catalytic properties of monovacancy and divacancy graphene sheets with two embedded Fe dopants (2Fe-MG and 2Fe-DG) have been systematically investigated using the first-principles calculations.

Surface restructuring of Cu-based single-atom alloy catalysts under reaction conditions: the essential role of adsorbates

The stabilities and catalytic performances of single-atom alloy (SAA) structures under the reaction conditions of acetylene hydrogenation are thoroughly examined utilizing density functional theory (DFT) calculations.