Dual functional materials prepared by two-step impregnation for ICCU-RWGS

Dual functional materials (DFMs) for ICCU-RWGS can be physically mixed adsorbent and catalyst, or one-unit catalytic sorbent, or adsorbent impregnated with catalyst. In this article, loading adsorbents with catalytic sites is introduced. The following information provides the preparation adsorbents and then the impregnation of the adsorbents with catalytic sites.

It is from this reference (

1) Adsorbent development – hydrotalcite

“PURAL® MG 20 hydrotalcite (Mg/Al molar ratio is 0.29) provided by Sasol Germany GmbH, Inorganic Specialty Chemicals was employed as the pristine material of the support. Potassium carbonate from Panreac was used as precursor of potassium component. All the metal precursors salts used in this study were the nitrate form purchased from Sigma-Aldrich. Deionized water was used for catalyst synthesis. The gases were purchased from Linde at the quality of >99.9993% for CO2 and >99.999% for the other gases.”

2) Loading adsorbents with catalysts by impregnation

“The hydrotalcite supported FeCrCu-K catalyst was prepared by sequential impregnation using the incipient wetness method. Firstly, a thermal treatment of hydrotalcite support at 600 °C for 3 h was carried out in order to obtain the homogeneous mixed oxides of MgO and Al2O3. Afterwards, three metals (Fe, Cr and Cu) were impregnated using a solution prepared by adding the necessary volume of deionized water to the metal nitrates precursor salts. The resulting solid was dried overnight at 80 °C followed by calcination at 500 °C for 5 h. Finally, a solution of potassium carbonate was impregnated over the solid obtained and it was dried and calcined under identical conditions. The elemental composition of the catalyst was determined by ICP analysis (Table S1-Supplementary material).”

The following preparation method is from another work (, which prepared the adsorbent (Na-Al2O3) firstly, and then loading Pt by impregnation.

“All catalysts were synthesized using the wetness impregnation method. For Pt–Na/Al2O3, Na and Pt species were immobilized over Al2O3 through the conventional impregnation method in a stepwise manner (Na followed by Pt). Al2O3 was first obtained by calcination of AlOOH at 900 °C for 3 h. Next, an appropriate amount of NaNO3 aqueous solution was impregnated on Al2O3 (Na2O: 3 wt %). After stirring for 3 h at room temperature, the suspension was evaporated over a vacuum pump at 50 °C and then dried at 100 °C overnight. The obtained solid was calcined at 600 °C for 2 h to afford Na-Al2O3. Afterward, (NH3)2Pt(NO3)2 was impregnated over Na-Al2O3 (Pt: 1 wt %) in the same manner, generating the as-calcined Pt–Na/Al2O3. Finally, Pt–Na/Al2O3 was obtained by H2 treatment of the as-calcined Pt–Na/Al2O3 at 350 °C. Other catalysts were synthesized using the same procedures with the Pt–Na/Al2O3 catalyst as described above.”

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