Steam reforming of ethanol to H-2 over Rh/Y2O3: crucial roles of Y2O3 oxidizing ability, space velocity, and H-2/C

Rh/Y2O3 is found to produce the highest rate of hydrogen in steam reforming of ethanol (SRE) at a high reaction temperature of 650-800 degrees C, with the order of catalyst activity as follows: Rh/Y2O3 > Rh/CeO2 > Rh/La2O3 > Rh/Al2O3. The activity of Rh/Y2O3 was significantly promoted due to the strong oxidizing ability of Y2O3 to oxidize the hydrogen of ethanol to form hydrogen gas. The optimal gas hourly space velocity (GHSV) of 105 000 h(-1) at 700 degrees C produced the maximum H-2/CO molar ratio and the highest hydrogen production rate. The catalyst efficiency in converting ethanol is directly reflected by H-2/C, which is a new indicator established for the first time and can be used to achieve the highest hydrogen production rate at the lowest carbon emission.