CO oxidation considered one of the most extensively studied reactions in the history of heterogeneous catalysis in the recent years. CO oxidation finds applications in many fields such as environmental protection especially air purification, long-life closed-cycle CO<sub>2</sub> lasers, CO detectors and has been used as a probe reaction in high-performance catalytic Reaction. The supported palladium-based catalyst is known for their high activity, recyclability, and their cheap cost when compared to platinum catalysts. Support plays a crucial role in the synthesis of the catalysts by reducing the metal loading, ensure a good dispersion, and increase their thermal stability. Mesoporous Silica is well known for structural and thermal properties and allows anchoring of catalytically palladium active species onto their surfaces and enhancing the catalytic activity due to its high surface area, highly porous, high thermal insulation, and local heating and heat retention properties. However, the experimental observations of the reaction kinetics of heterogeneous CO oxidation under reaction conditions showed a complicated dynamic behavior such as kinetic instabilities, and self-sustained oscillations and the formation of hysteresis phenomena in heterogeneous exothermal catalytic CO oxidation.<br/>To understand the reaction mechanism of supported palladium clusters or particles under reaction conditions. Our group carried out a series experiments to study the effect of reaction parameters such as (metal loading, flow rate, heating rate, and catalyst weight) on the width of the hysteresis loop and CO conversion as a function of temperature during ignition and extinction exothermic reaction experiments with constant CO and O2 concentrations.<br/>Heren, we report for the first time exceptional catalytic CO oxidation on Pd supported on mesoporous SiO2 Aerogel with excellent stability and recycling behavior during ignition and extinction exothermic reaction conditions. The results revealed a substantial activity-temperature hysteresis loop where activity was stable with reaction time where the CO oxidation self-sustained oscillation remains upon decreasing the temperature until reaching the extinction temperature near ambient temperature with wide CO thermal hysteresis (close to 200 C). Also, we report the effect of the reaction parameters on the width of the hysteresis loop. Our results indicate that flow rate has a significant impact on the width of the loop.

Self-sustaining and hysteresis behavior of low-temperature CO oxidation on mesoporous Pd/SiO2 aerogel s catalyst under dynamics conditions

256th National Meeting (2018)

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