Investigation of palladium catalysts in mesoporous silica support for CO oxidation and CO2 adsorption

The oxidation of Carbon monoxide (CO) to Carbon dioxide (CO2) is one of the most extensively investigated reactions in the field of heterogeneous catalysis, and it occurs via molecular rearrangements induced by catalytic metal atoms with oxygen intermediates. CO oxidation and CO2 capture are instrumental processes in the reduction of green-house gas emissions, both of which are used in low-temperature CO oxidation in the catalytic converters of vehicles. CO oxidation and CO2 adsorption at different temperatures are evaluated for palladium-supported silica aerogel (Pd/SiO2). The synthesized catalyst was active and stable for low-temperature CO oxidation. The catalytic activity was enhanced after the first cycle due to the reconditioning of the catalyst's pores. It was found that the presence of oxide forms of palladium in the SiO2 microstructure, influences the performance of the catalysts due to oxygen vacancies that increases the frequency of active sites. CO2 gas adsorption onto Pd/SiO2 was investigated at a wide-ranging temperature from 16 to 120 degrees C and pressures similar to 1 MPa as determined from the isotherms that were evaluated, where CO2 showed the highest equilibrium adsorption capacity at 16 degrees C. The Langmuir model was employed to study the equilibrium adsorption behavior. Finally, the effect of moisture on CO oxidation and CO2 adsorption was considered to account for usage in real-world applications. Overall, mesoporous Pd/SiO2 aerogel shows potential as a material capable of removing CO from the environment and capturing CO2 at low temperatures.

Automated summary

The oxidation of CO to CO2 via molecular rearrangements induced by catalytic metal atoms with oxygen intermediates is extensively studied in heterogeneous catalysis. This reaction is essential for reducing greenhouse gas emissions, particularly in low-temperature CO oxidation in vehicle catalytic converters. The catalytic activity of the palladium-supported silica aerogel (Pd/SiO2) catalyst was enhanced after the first cycle, attributed to the reconditioning of its pores. The presence of oxide forms of palladium in the SiO2 structure influenced the catalyst's performance by increasing the frequency of active sites. Additionally, the adsorption of CO2 onto Pd/SiO2 was evaluated, and the Langmuir model was employed to study the equilibrium adsorption behavior. Overall, the mesoporous Pd/SiO2 aerogel shows promise as a material for CO removal and CO2 capture at low temperatures.