Dr Wu’s group initially reported that pure CaO could act as sorbent and catalyst for ICCU-RWGS without transition metals; and high efficiency and conversion were reported (https://doi.org/10.1016/j.ccst.2021.100001).
In this work (https://doi.org/10.1016/j.jcou.2022.102049), transition metal free Na/Al2O3 DFMs were prepared using simple impregnation methods, as below (copied from the previous reference):
“γ-Al2O3 (Neobead MSC#300, Mizusawa Industrial Chemicals, Ltd.) was used as a support for the DFM. Na2CO3, K2CO3, and Ca(NO3)2･4 H2O (guaranteed reagent, Fujifilm Wako Pure Chemical Corp.) were used as precursors. Table 1 lists the DFMs prepared. All the DFMs were prepared by the impregnation method as follows: Initially, γ-Al2O3 was impregnated with an aqueous solution containing a predetermined amount of one of the precursors, and subsequently dried at 110 °C for 12 h. The dried samples were calcined in air at 550 °C for 4 h to obtain Na/Al2O3, K/Al2O3, and Ca/Al2O3, according to the selection of precursor. The alkali and alkaline earth metal loading was set at 1.5 mmol per 1 g of DFM in carbonate form.” (https://doi.org/10.1016/j.jcou.2022.102049)
