Enhancement of catalytic activity over Cu-supported montmorillonite catalyst for hydrogen production via steam reforming of dimethyl ether.

Cu-Co/X-MMT (X = Na, SiO₂) catalysts were prepared via impregnation method using Na-MMT and SiO₂-MMT (montmorillonite pillared by SiO₂) as the support and copper nitrate and cobalt nitrate as precursors. In addition, the citric acid was introduced during the preparation of Cu-Co/SiO₂-MMT to obtain Cu-Co/SiO₂-MMT-Ac catalyst. The catalysts were characterized by XRD, TEM, H₂-TPR, XPS and N₂ adsorption–desorption at low temperature. The results showed that the acidity and specific surface area of SiO₂-MMT were larger than those of Na-MMT, thus resulting in dimethyl ether (DME) conversion and H₂ yield of Cu-Co/SiO₂-MMT higher than those of Cu-Co/Na-MMT during steam reforming of DME (SRD). However, for Cu-Co/SiO₂-MMT, there was a large amount of methanol in the carbon-containing product due to the large particle size of Cu. The Cu particle size of Cu-Co/SiO₂-MMT-Ac was decreased significantly due to the introduction of citric acid, thus accelerating the steam reforming of methanol reaction and enabling the timely conversion of the intermediate product methanol of SRD, resulting in the increasing DME conversion and H₂ yield. Therefore, Cu-Co/SiO₂-MMT-Ac was expected to be a potential catalyst for SRD. [ABSTRACT FROM AUTHOR]