Biohydrogen production from catalytic conversion of food waste via steam and air gasification using eggshell- and homo-type Ni/Al₂O₃ catalysts

Steam and air gasification with 5 wt% Ni/Al₂O₃ eggshell (Ni-EG) and homo (Ni-H) catalysts were performed for the first time to produce biohydrogen from food waste. The steam gasification produced comparably higher gas yield than air gasification. In non-catalytic experiments, steam gasification generated a higher volume percent of H₂, whereas more CO, CO₂, CH₄, and C₂-C₄ were produced in air gasification. Ni-EG demonstrated higher potential to obtain H₂-rich gases with a low C₂-C₄ content compared to that obtained by Ni-H, particularly in steam gasification at 800 °C, which produced gaseous products with 59.48 vol% H₂. The long-term activity of both catalysts in steam gasification was evaluated, and Ni-EG exhibited higher stability than Ni-H. The ideal distribution of Ni species on the outer region of γ-Al₂O₃ pellets in Ni-EG resulted in higher activity, stability, and selectivity than Ni-H in both steam and air gasification.