Hydrogen production by auto-thermal reforming of ethanol over Ni catalyst supported on ZrO2 prepared by a sol–gel method: Effect of H2O/P123 mass ratio in the preparation of ZrO2

Zirconia (X-ZrO2) supports were prepared by a sol–gel method using P123 as a crystal structure and physical property controlling agent with a variation of H2O/P123 mass ratio (X). 20 wt.% Ni catalysts supported on X-ZrO2 (X = 2, 3, 4, and 5) were then prepared by an incipient wetness impregnation method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of H2O/P123 mass ratio (X) on the catalytic performance of Ni/X-ZrO2 (X = 2, 3, 4, and 5) catalysts was investigated. Crystal structure and physical property of zirconia could be controlled by changing the H2O/P123 mass ratio during the preparation step. All the Ni/X-ZrO2 (X = 2, 3, 4, and 5) catalysts exhibited complete conversion of ethanol at 500 °C, while product distributions over Ni/X-ZrO2 (X = 2, 3, 4, and 5) catalysts were different depending on the H2O/P123 mass ratio. Hydrogen selectivity over Ni/X-ZrO2 (X = 2, 3, 4, and 5) catalysts was monotonically increased with increasing reducibility of the catalyst and with increasing H2O/P123 mass ratio. Among the catalysts tested, Ni/5-ZrO2 with pure tetragonal phase of zirconia showed the best catalytic performance in hydrogen production by auto-thermal reforming of ethanol. High surface area and small nickel crystalline size of Ni/5-ZrO2 were also responsible for high catalytic performance of Ni/5-ZrO2 catalyst.