About 750 cycles of ICCU-RWGS were carried out using FeCrCu-K supported on hydrotalcite (https://doi.org/10.1016/j.jcou.2016.04.003). The dual functional materials were prepared by simple wet impregnation. The experiments were carried out under 5.8%CO2 while the reaction temperature was 550 °C. In addition, the amount of materials for each test was around 1 g and the particle size was between 200 and 300 um. As shown in the following figure, the dual functional materials showed excellent stability over the 750 cycles, without showing any deactivation in relation to the CO2 capture efficiency. The presence of moisture and oxygen did not affect the carbon capture efficiency during the 750 cycles. However, the conversion of the captured CO2 was largely reduced when the atmosphere was realistic (containing moisture and O2). The ICCU-RWGS cyclic process also showed excellent CO selectivity over the 750 cycles. The in-time concentration of gases (left side of the figure) indicates that CO and CO2 are the main gas components, except H2. However, this work does not report the absolute value of CO production per unit of dual functional materials. The high stability of materials might be related to the low capacity of CO2 capture and low yield of CO production. This could be reflected from this work that a high H2/CO ratio was obtained (around 40). The authors also mentioned that the composition of the product is related to the applications. This should be considered in the future, as near 100%CO2 conversion might not be needed, considering CO2 in syngas could be directly utilised during the application of syngas, such as methanol production.
“Figure – (A) Evolution of CO2 conversion, capture efficiency and CO selectivity during 750CCR cycles (45 h) under the ideal and realistic conditions at 550 °C with 5.8% CO2 in capture phase. (B) Representation of the concentration profiles of the last CCR cycle.”