Hydrogen production via aqueous phase reforming of glycerol over Ni-Co/γ-Al2O3 catalysts: Effect of support modification with lanthanides and alkaline earth metals

Abstract

Aqueous phase reforming (APR) of glycerol on Ni-Co/γ-Al₂O₃ catalysts was evaluated, studying the effects of support modification with promoters (Ca, Mg, La, Ce). Catalysts were characterized by N₂ adsorption–desorption, H₂-TPR, CO₂-TPD, pyridine-TPD, TEM, XRD, XPS and TPO measurements. Catalytic performance tests were carried out in a continuous flow fixed-bed reactor at 225 °C, 25 bar, and two WHSV (2.45–4.90 h⁻¹) with solution of 10 wt% glycerol during 7 h-on-stream; additional tests were done at different temperatures (210–240 °C). Catalysts promoted with Ca, Mg, and La showed an enhanced H₂ production compared to the unmodified sample at 2.45 h⁻¹ WHSV, with ≈ 50 % glycerol conversion and a H₂ selectivity between 70 and 85 %. At 4.90 h⁻¹ WHSV and 225 °C, the Ca-promoted sample reached 660 µmol.h^−1.g_cat^-1 H₂ production, 30 % glycerol conversion, and 80 % H₂ selectivity, displaying the best catalytic performance. Raising the reaction temperature to 240 °C, H₂ production was 840 µmol.h⁻¹.g_cat^-1 with Ni-Co/Ca-Al₂O₃.