Catalytic gasification of indole in supercritical water with non-noble bimetallic catalysts. (November 2022) - Hao, Botian
Abstract: Indole is commonly reported as a N-containing heterocyclic compounds in biomass supercritical water gasification (SCWG), and is difficult to be degraded to small molecule substances. In this work, Ni/AC, Ni–Cu/AC, Ni–Co/AC, Ni–Ce/AC were prepared and tested for catalytic SCWG of indole. The results showed that Ni–Cu/AC had the highest activity for converting indole and producing gases, leading to the highest hydrogen gasification efficiency (135.1%) and carbon gasification efficiency (33.1%). During the catalytic SCWG of indole, the addition of auxiliary metal Cu in multi-component catalyst showed synergistic effects by changing reaction pathways and reaction rates. It significantly promoted water-gas shift and steam reforming reactions, so forming the highest H2 yield of 2.62 mol mol −1 . Furthermore, large specific surface, Ni reduction and high catalyst stability point to potential advantages of the Ni–Cu/AC catalyst for catalytic SCWG of recalcitrant N-containing compounds. Graphical abstract: Image 1 Highlights: SCWG of indole was conducted over various Ni based non-noble bimetallic catalyst. Maximum HGE of 135.13% and CGE of 33.05% were achieved with Ni–Cu/AC catalyst. Water gas conversion reaction and steam reforming reaction of indole SCWG were significantly promoted by Cu. The addition of auxiliary metal effectively reduced NiO in nickel based catalysts and inhibited the oxidation of Ni.