Highly selective and stable Cu-based dual-function materials for integrated CO2 capture and in-situ conversion to CO

• Cu-based DFMs (Cu/Na-CaO/γ-Al 2 O 3 ) were prepared using Na-promoted CaO sorbent and alumina support. • Cu content has a significant impact on DFMs physiochemical properties and overall performance. • Temperature plays a crucial role in balancing the rates of decarbonation and RWGS, determining the CO 2 conversion efficiency. • DFMs selectively favor the RWGS reaction while inhibiting the coexistence of methanation, regardless of temperature. • DFMs exhibited high efficiency under an O 2 -containing atmosphere while showing a slight decrease in CO 2 capture and conversion. • Excellent stability was confirmed over 18 non-isothermal ICCC-RWGS cycles with CO 2 . Integrating carbon capture and conversion by reverse water–gas shift reaction (ICCC-RWGS) represents an innovative and promising CO 2 mitigation and valorization strategy. Nevertheless, developing efficient and stable dual-function materials (DFMs) offering both high CO 2 conversion and CO selectivity remains very challenging. Herein, we developed a new series of highly selective DFMs (Cu/Na-CaO/γ-Al 2 O 3 , denoted as Cu X NaCa Y Al Z ; where NaCa and Al represent Na-CaO and γ-Al 2 O 3 , respectively) tailored for the ICCC-RWGS process and evaluated their performance in different conditions. The findings highlight the substantial impact of Cu content on DFM performance by modulating its physiochemical properties. All DFMs exhibited a 100 % CO selectivity, regardless of temperature. Despite a slight decrease in CO 2 uptake and conversion in the presence of oxygen compared to ideal conditions, Cu 10 NaCa 30 Al 60 demonstrated remarkable stability with no decline in CO 2 conversion over 12 cycles. While CO 2 capture capacity improved with increasing temperatures up to 650 °C, the slower decarbonation rate at lower temperatures created a more favorable equilibrium between decarbonation and RWGS rates, leading to higher conversion. Subsequently, a non-isothermal ICCC-RWGS was proposed, with CO 2 capture at 650 °C and hydrogenation at 610 °C. Cu 10 NaCa 80 Al 10 exhibited remarkable stability over 18 cycles, showing an increasing CO 2 capture and CO formation trend, peaking at the 14th cycle before stabilizing, while maintaining a consistently high CO 2 conversion of approximately 91 %.