Effect of lattice oxygen in nickel-based catalysts with different support on coke resistance of filamentous coke in CO2 reforming of tar

Abstract

ABSTRACT For CO2 reforming of tar, deactivation of catalysts caused by filamentous coke deposition limits its application in solid waste treatment. The filamentous coke removal can be aided by the lattice oxygen of active mental sites, however, there is no information on the influence of lattice oxygen in catalyst support on filamentous coke oxidation. To investigate the activity and resistance to coke deposition of different catalysts, based on a comparison of the performance of Ni/ZrO2, Ni/SiO2, Ni/MgO, and Ni/attapulgite catalysts, the influence of lattice oxygen on filamentary coke deposition is investigated in this study. In CO2 catalytic reforming experiments, the Ni/ZrO2 catalysts showed higher coke conversions (10%–23%) than the Ni/SiO2, Ni/MgO, and Ni/attapulgite catalysts. In the meantime, the lattice oxygen coverage of the Ni/ZrO2 superficies reaches 55.59%, giving Ni/ZrO2 a better resistance to filamentary coking. The high lattice oxygen coverage also improves the oxidation of the coke superficies by lattice oxygen. However, there was still 31.66% filamentary coke aggregation on the Ni/ZrO2 catalyst superficies. In conclusion, inhibiting the formation of filamentous coke and promoting the oxidation of filamentous coke are key to improving the efficiency of CO2 reforming of anaerobic tar. The results of the research can be used as a reference for the improvement of catalysts.