CO2 reforming of CH4 over Ni-containing phyllosilicates as catalyst precursors

CO2 reforming of CH4 to synthesis gas was investigated on new grounds using Ni-containing phyllosilicates (PS) as catalyst precursors. Ni-containing 1:1 PS and 2:1 PS were synthesized hydrothermally from a gel containing sodium silicate and nickel chloride, then they were reduced under H2 flow before being used as catalysts. Several complementary techniques including XRD, TG-DTA, FTIR, and TPR were used to evaluate the structural, thermal, spectroscopic and redox properties of the samples, respectively. Ni 2:1 PS were found to be more thermally stable and catalytically active than Ni 1:1 PS. Well crystallized Ni 1:1 PS thermally treated at 700 °C resulted in a transitional 2:1 PS phase. The reduction of structural nickel in thermally stable PS led to the formation of nanometric Ni0 particles over the surface of the remaining unreduced PS as well as on silica. The unreduced PS structure with surface OH groups appeared as one of the best supports for Ni0 nanoparticles, resulting in less coke formation, and thereby leading to a high catalytic stability.