Influence of La2O3 composition in MgO–La2O3 mixed oxide-supported Co catalysts on the hydrogen yield in glycerol steam reforming

Abstract

MgO–La₂O₃ mixed oxide (MLx) supports with varying La₂O₃ content (x = 1, 2, 3, 4, and 5 by wt) were synthesized by a co-precipitation method. A constant composition (20 wt%) of an active metal, cobalt, was loaded on MLx supports by the wet impregnation method. The physico-chemical properties of these solids were determined by BET surface area, ICP-OES, XRD, H₂-TPR, CO₂-TPD, FT-IR, H₂-pulse chemisorption and CHN techniques. All the catalysts were evaluated for hydrogen production by vapor phase glycerol steam reforming at atmospheric pressure. Partial substitution of La in LaCoO₃ with MgO has increased the reducibility of the perovskite, enhanced the dispersion of the active metal and played a vital role in carbon removal from the active site. The best catalytic activity with 100% glycerol conversion to gas products (H₂, CO, CH₄ and CO₂) and a maximum hydrogen yield of 72.8% has been achieved for 20 wt% of the Co/1MgO : 3La₂O₃ catalyst at 700 °C. The catalyst activity also remained stable up to 35 h on stream analysis.