Solid sorbents represent a promising strategy for carbon capture due to their low energy requirements, ease of operation, and long-term stability. In this study, we introduce perovskite oxides as a highly tunable class of solid sorbents, offering exceptional structural and compositional flexibility that allows precise control over CO2 adsorption thermodynamics and kinetics. Using the SrxLa1-xFeO3 system (x = 0, 0.2, 0.5, 0.7) as a model, we demonstrate that modifying the A-site composition significantly influences CO₂ adsorption and desorption behavior, enabling controlled release over a broad temperature window (75–500+ °C). A strong correlation was observed between surface area and CO2 sorption capacity. While traditional perovskites typically have low surface areas (3–5 m²/g via salt-assisted reactive grinding), we increased this value to approximately 30 m²/g using an electrospinning technique. Among the synthesized compositions, Sr0.2La0.8FeO3 showed a moderate desorption onset at 120 °C and a peak at 240 °C, along with a sorption capacity of 0.68 wt.%. CO2 adsorption isotherms indicated dominant chemisorption at low partial pressures (0–1 kPa), with physisorption becoming more prominent at higher pressures. TEM analysis revealed nanorod morphologies, and XPS measurements confirmed an increased surface concentration of La, which is strongly associated with enhanced sorption reversibility. We also successfully extended the cation doping strategy on other inorganic oxides such as γ-alumina. Specifically, γ-Al₂O₃ with 10 wt.% Ca doping exhibited superior CO2 sorption capacity and excellent performance for integrated CO2 capture and conversion.
