Seeded-growth preparation of high-performance Ni/MgAl2O4 catalysts for tar steam reforming†
Abstract
Tar removal is a great challenge preventing the commercialization of the biomass gasification technology for power generation. In this study, a series of Ni/MgAl2O4 compounds with different nickel contents were prepared by a seeded-growth strategy without surfactants, and employed as the catalysts for steam reforming of toluene which is considered as a tar model. These catalysts exhibited good catalytic activity, carbon deposition resistance and anti-sintering properties, especially 20Ni/MgAl2O4, which could achieve 100% gas yield with no more than 0.359% of solid carbon selectivity, and its catalytic performance did not decrease even after 600 min operation. The characterization results demonstrated that the catalyst prepared by this method showed several desirable properties, such as small Ni particle size, high dispersity of Ni on the MgAl2O4 support, high specific surface area, uniform mesoporous structure, and appropriate basic properties. In addition, DFT calculations indicated that there is a competitive adsorption of H2O and C7H8 on Ni5 clusters, and H2O is easier to adsorb on the Ni5 cluster than C7H8.