Modification of silica supported nickel catalysts with lanthanum for stability improvement in methane reforming with CO2

Dry reforming of methane (DRM) with excessive methane composition at CH4/CO2 = 1.2:1 was studied over lanthanum modified silica supported nickel catalysts (Ni-xLa-SiO2, x: 1, 4, and 6% in the target weight percent of La). The catalysts were prepared by ammonia evaporation method. Nickel phyllosilicate and La2O3 were the main phases in calcined catalysts. The modification of La enhanced the formation of 1:1 and Tran-2:1 nickel-phyllosilicate. There existed an optimum content of La loading at 1.50 wt% in Ni-2La-SiO2 which resulted in its highest reduction degree (95.3%). The catalysts with appropriate amounts of La exhibited higher amount of CO2 adsorption and created more medium and strong base centers. The sufficient number of exposed metallic nickel sites to catalyze the reforming reaction, as well as enough medium and strong basic sites in Ni-La-SiO2 interface to accomplish the carbon removal were two important factors to attenuate catalyst deactivation. The catalyst stability evaluated at 750 degrees C for 10 h followed the order: Ni-2La-SiO2 > Ni-4La-SiO2 > Ni-1La-SiO2 z Ni-6La-SiO2 > Ni-SiO2. Ni-2La-SiO2 catalyst possessed the lowest deactivation behavior, whose CH4 conversion dropped from 60.2 to 55.9% after 30 h operation at 750 degrees C, indicating its high resistance against carbon deposition and sintering.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the effects of nickel catalysts modified with lanthanum on the efficiency and stability of dry reforming of methane process. It was found that the appropriate addition of lanthanum could enhance the CO2 adsorption capacity of the catalyst, increase the ability to remove carbon, and thus mitigate catalyst deactivation.