Renewable hydrogen production by aqueous-phase reforming of Glycerol using Ni/Al2O3-MgO nano-catalyst: effect of the Ni loading

Abstract

Aqueous-phase reforming (APR) of oxygenated hydrocarbons for hydrogen production presents several advantages as feed molecules might be easily found in a wide range of biomass; there is no need for its vaporization and the process allows thorough exploitation of the environmental benefits of using hydrogen as an energy carrier. In this contribution, catalysts with active phase Ni supported on Al2O3-MgO were synthesized at different loadings (1, 3, 5, 7, and 10 wt%) through the co-precipitation technique and tested for the Glycerol APR reaction. Effects of the Ni loading on physicochemical characteristics of Ni/Al2O3-MgO catalysts were examined. Moreover, catalytic performance was investigated in order to determine the optimum catalyst for H2 production in APR of Glycerol. The catalysts were characterized by the XRD, BET-BJH, TPR, and TEM analyses. The reaction was carried out in a fixed-bed reactor with solution of 10 wt% Glycerol at 250 °C and 50 bar. Results revealed that the APR activity of synthesized catalysts strongly depended on the Ni loading. In addition, it was considered a foregone conclusion that, among the synthesized catalysts, catalytic activity increased through enhancement of the Ni loading up to 5 wt%. Furthermore, the 5 wt% Ni/Al2O3-MgO nano-catalyst possessed highest catalytic activity of 92% total conversion and selectivity towards hydrogen production of 76%. It was concluded that the APR activity lowered in the following order: 5 > 3 > 1 > 7 > 10 wt% Ni/Al2O3-MgO.