Adsorption–desorption of CO2 on different type of copper oxides surfaces: Physical and chemical attractions studies

• The adsorption of CO2 on CuO surfaces is favourable (ΔG = +4.9 kJ mol−1) under standard conditions.
• By XPS, 52.4% of carbonates (CO32−) was formed and growth on CuO surface.
• Higher amount of CO2 was physically (9 cm3/g sample) and chemically (9.5 mmol) adsorbed.

By thermodynamics considerations, it was shown that the adsorption of CO2 on CuO surfaces is favourable (ΔG = +4.9 kJ mol−1) under standard conditions (1 atm and 298 K). Various analytical methods such as FTIR, BET, TPD-CO, TGA, XRD, XPS and FESEM were carried out to determine the properties of Cu2O and CuO and CO2 adsorption performance. Surface analysis by XPS, it was noted that 52.4% of carbonates (CO32−) was formed and deposited on CuO surface. By BET-CO2 method, typical amount of CO2 was adsorbed (9 cm3 per gram sample) at relative pressure of 0.78. It was relatively high compared to Cu2O with 2.1 cm3 per gram sample. The sphere-flower structure of CuO gives a better adsorption and desorption behaviour. Copper carbonate (CuCO3) formed after CO2 adsorption was heated up until 573 K as a regeneration study of adsorbent materials. No significant loss was measured until three times regeneration. The desorption studies using TPD-CO2 indicated that about 9.5 mmol of CO2 was captured at room temperature.

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