Opinion

A Preliminary Investigation of CO₂ Adsorption on Palladium Catalysts in Mesoporous Silica Support

Naif Alarifi*

*Institute of Refining and Petrochemicals Technologies, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia

Submission: August 18, 2024;Published:March 19, 2025

*Corresponding author:Naif Alarifi, Institute of Refining and Petrochemicals Technologies, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia

How to cite this article:Naif A. A Preliminary Investigation of CO2 Adsorption on Palladium Catalysts in Mesoporous Silica Support. Eng Technol Open Acc 2025; 6(3): 555687.DOI: 10.19080/ETOAJ.2025.06.555687

Introduction

Increasing interest in carbon capture, sequestration, and CO₂ capture are instrumental processes in the reduction of greenhouse gas emissions. Palladium-supported silica with 0.5 and 1% Pd/SiO₂ were examined for CO₂ sorption at various temperatures and pressures.

CO₂ gas was studied for sorption onto Pd/SiO₂ with temperatures between 22, 25, and 50°C and pressures between 0.3 and 2.25 bar, where the equilibrium adsorption capacity in CO₂ reached its highest value at 0.5 Pd/SiO₂ and 22°C.

On the flip side, a significant amount of CO₂ is a greenhouse gas and a significant factor in global warming and climate change. In recent years, there has been a rise in interest in the development of a material that can act as a sorbent for CO₂ storage at lower temperatures due to the possibility of mitigating CO₂ emissions in order to protect the environment.

The aim of this work is to investigate how to improve the pathways used to capture CO₂ and remove toxic gases from the environment. For this purpose, the adsorption-desorption experiments were conducted at different temperatures and pressures. This primary study presents a behavior of the used material for studying their CO₂ adsorption capabilities

Adsorption Study

The CO₂ storage studies were performed using a High Pressure Volumetric Analyzer (HPVA), that measured the adsorption/desorption isotherms of CO₂ gas at different temperatures and pressures. Before the adsorption measurements, the samples were degassed at 350°C for 5 hours and exposed to flotation in a helium at atmosphere to inspect the mass and skeleton volume of the loaded sample.

(Figure 1) shows the measured adsorption/desorption isotherms of CO₂ at different temperatures; 22, 25, and 50°C. Overall, it revealed that the adsorption capacity of CO₂ decreases by increasing the temperature and loaded percentage of Palladium. Furthermore, the adsorption/desorption capacity of CO₂ gas onto Pd/SiO₂ increases by increasing the pressure at all temperatures. The highest and lowest adsorption capacity for CO₂ on Pd/SiO₂ at a pressure of ~2.15 bar were 20 cm³/g and 12 cm³/g at 22 and 50°C, respectively. It is to be noted that the adsorption and desorption data were almost identical, without any noticeable lag. According to the data, Pd/SiO₂ performs well in the adsorption of CO₂ and has a type-I adsorption isotherm, which allows for its regeneration by decreasing pressure or increasing temperature. At high temperatures in a small pressure range, there are small deviations from experimental data observed, The Langmuir model fitting was generally in good agreement with experimental data at all temperatures and throughout the entire pressure range, as observed in (Figure 1).

Conclusion

Stable palladium nanoparticles supported on mesoporous silica (Pd/SiO₂) were assessed for their ability to capture CO₂ at different temperatures and pressures. The absorption of CO₂ gas by Pd/SiO₂ was effective, particularly at low temperatures (such as 22°C). It would be feasible to suggest using the Pd/SiO₂ material for CO₂ adsorption. The absolute experimental CO₂ concentrations were accurately correlated using the Langmuir adsorption isotherm model with temperature and pressure. The findings indicate that Pd/SiO₂ catalysts are capable of providing low-cost and environmentally friendly methods for capturing CO₂ at low temperatures.