Catalytic gasification of food waste in supercritical water over La promoted Ni/Al2O3 catalysts for enhancing H2 production

Ni/Al 2 O 3 catalyst is the one of promising catalysts for enhancing H 2 production from supercritical water gasification (SCWG) of biomass. However, due to carbon deposition , the deactivation of Ni/Al 2 O 3 catalyst is still a serious issue. In this work, the effects of lanthanum (La) as promoter on the properties and catalytic performance of Ni/Al 2 O 3 in SCWG of food waste were investigated. La promoted Ni/Al 2 O 3 catalysts with different La loading content (3–15 wt%) were prepared via impregnation method. The catalysts were characterized using XRD , SEM, BET techniques. The SCWG experiments were carried out in a Hastelloy batch reactor in the operating temperature range of 420–480 °C, and evaluated based on H 2 production. The stability of the catalysts was assessed by the amount of carbon deposition on catalyst surface and their catalytic activity after reuse cycles. The results showed that 9 wt% La promoter is the optimal loading as Ni/9La–Al 2 O 3 catalyst performed best performance with the highest H 2 yield of 8.03 mol/kg, and H 2 mole fraction of 42.46% at 480 °C. La promoted Ni/Al 2 O 3 catalysts have better anti-carbon deposition properties than bare Ni/Al 2 O 3 catalyst, resulting in better gasification efficiency after reuse cycles. Ni/9La–Al 2 O 3 catalyst showed high catalytic activity in SCWG of food waste and had good stability as it was still active for enhancing H 2 production when used in SCWG for the third time, which indicated that La promoted Ni/Al 2 O 3 catalysts are potential additive to improve the SCWG of food waste.