Which is the better catalyst for CO2 methanation – Nanotubular or supported Ni-phyllosilicate?

Abstract

In order to investigate effects of morphology and crystalline phase of different Ni-phyllosilicate catalysts on the catalytic performance for CO2 methanation, nanotubular Ni-phyllosilicate and MCM-41 supported Ni-phyllosilicate were synthesized through hydrothermal reaction of sodium silicate or MCM-41 with nickel nitrate. On one hand, nanosheets attributing to 2:1 type nickel phyllosilicate (Ni3Si4O10(OH)2·5H2O) were uniformly grown on the surface of MCM-41 spheres to form the MCM-41 supported Ni-phyllosilicate (Ni/M). On the other hand, 1:1 type Ni-phyllosilicate with nanotubular morphology (Ni/N) was synthesized through the reaction of Na2SiO3 and nickel nitrate. After a series of tests and characterizations, it was found that Ni/N exhibited low thermal stability and poor anti-sintering property, leading to poor catalytic activity for CO2 methanation. On the contrary, Ni/M was very stable, which obtained unchanged morphology and fine Ni particles after 750oC-reduction, resulting in high catalytic activity and long-term stability for CO2 methanation. In all, morphology and crystalline phase of Ni-phyllosilicate obviously affected catalytic performance, and the supported Ni-phyllosilicate catalyst was much better than the nanotubular Ni-phyllosilicate for CO2 methanation in this work.