Lanthanum incorporated in MCM-41 and its application as a support for a stable Ni-based methanation catalyst

Herein, lanthanum was incorporated via hydrothermal synthesis into a MCM-41 framework structure with La/Si molar ratios from 0.01 to 0.1. Samples of NiO supported on LaMCM-41 were prepared using the impregnation method. The catalyst performance was evaluated using a fixed bed CO methanation reactor. A Ni/LaMCM-41 catalyst with La/Si = 0.1 shows the best catalytic performance with a CO conversion of almost 100% and a CH4 selectivity of 89.5% at 250 degrees C under a pressure of 1.5 MPa and at an airspeed of 36,000 mL/(g.h). Compared with NieLa/MCM-41(La/Si = 0.1) and Ni/MCM-41 prepared via the impregnation method, Ni/LaMCM-41(La/Si = 0.1) shows a higher CO conversion and CH4 selectivity. In a 100 h stability test, the Ni/LaMCM-41(La/Si = 0.1) catalyst shows excellent stability; furthermore, the CO conversion is always greater than 98.0%, which is significantly better than the results for Ni/MCM-41. We experimentally demonstrate that elemental La enters the framework of MCM-41. The Ni/LaMCM-41 catalyst performs well because the La reduces the average particle size of the NiO particles and enhances the interaction between NiO and MCM-41; moreover, the introduction of La significantly inhibits the sintering of the catalyst and the formation of carbon deposits. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.