Advanced microporous carbon adsorbents for selective CO2 capture: Insights into heteroatom doping and pore structure optimization

Given the rising CO2 emissions and their contribution to the greenhouse effect, mitigating their adverse effects on the climate is crucial. One of the most efficient methods for capturing and reducing CO2 emissions is through adsorption using microporous carbon materials, which offers an effective separation technique to prevent these emissions from entering the atmosphere. In this study, a cost-effective and eco-friendly nitrogen and sulfur-co- doped porous carbon material originated from phenol-formaldehyde resin was synthesized by thiourea modification and KOH activating approch, for advanced CO2 capture. The material was thoroughly characterized, and its physical and chemical properties were evaluated. By varying the activating temperature and amount of KOH, the as-prepared N/S co-doped porous carbons depicted advanced porous structure, with nitrogen/sulfur incorporated throughout the carbon matrix. The optimized N/S co-doped porous carbon showed excellent CO2 adsorption capacities, reaching 4.46 mmol/g at 25 degrees C and 6.38 mmol/g at 0 degrees C under 1 bar pressure. Furthermore, the material demonstrated good CO2/N2 selectivity, moderate isosteric heat of adsorption, fast adsdsorption kinetics, excellent dynamic CO2 capture capacity and strong cyclic stability. The superior CO2 capture features were primarily attributed to the material's well-developed microporous matrix and the even distribution of nitrogen and sulfur functional groups within the carbon framework. In summary, this study highlights the promising capability of heteroatom-doped porous carbon adsorbents as selective CO2 adsorbents, offering an effective approach to addressing CO2 reduction challenges.