Rh/Ce-SBA-15: Active and stable catalyst for CO2 reforming of ethanol to hydrogen

CO2 reforming of ethanol has been investigated for hydrogen production by reacting CO2, which is a greenhouse gas, with ethanol, which is a renewable energy source, over Rh/Ce-SBA-15 catalysts. A series of Rh/Ce-SBA-15 catalysts have been prepared using Ce-SBA-15 supports with different Ce/Si molar ratio synthesized by direct synthesis method. The catalysts have been characterized by TEM, FESEM, XRD, BET, TPR, TPD and XPS. All samples show high surface area and mesoporous structure at high Ce/Si (= 0–1/5), whereas the mesoporous structure is destroyed at high Ce/Si molar ratio (= 1/1). The catalytic tests show that the Ce/Si molar ratio of the catalysts has significant influence on the hydrogen production rate and product selectivity. The optimal Ce/Si molar ratio for the highest hydrogen production rate is found to be 1/20. The increase of catalytic activity of 1%Rh/Ce-SBA-15 from Ce/Si = 0 to Ce/Si = 1/20 is attributed to the increase of the amount of Ce incorporated into SBA-15 framework, resulting in the enhancement of the mobility of surface oxygen species. The 1%Rh/Ce-SBA-15 (Ce/Si = 1/20) is found to be the most active, selective and stable catalyst for CO2 reforming of ethanol to syngas or hydrogen.