Highly dispersed Ni/montmorillonite catalyst for glycerol steam reforming: Effect of Ni loading and calcination temperature

Abstract

Montmorillonite (MMT) supported nickel nanoparticles (Ni/MMT) were prepared by an ultrasound assisted cation exchange impregnation method with rising pH technique. The Ni/MMT catalysts were characterized by different techniques including thermogravimetric analysis (TGA), N2 adsorption-desorption, X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), temperature programmed reduction (TPR), and temperature programmed oxidation (TPO). The characterization results showed the particle size, metal-support interaction, nickel dispersion interrelated with cation exchange capability and confinement effect of montmorillonite lamellar structure. The activity and stability tests were conducted in a fixed bed reaction and the reaction parameters of 600°C and S/C=3 were optimized. The effect of Ni loadings and calcination temperature were investigated. The results show that the Ni dispersion, particle sizes of Ni and metal-support interaction (MSI) are closely dependent on the Ni loading and calcination temperature. The MMT support favors dehydrogenation reaction pathway which is effective to suppress the coke deposition and the lamellar structure could provide strong confinement effect which is effective to inhibit Ni sintering. The phyllosilicate content in MMT could promote WGS reaction which is conducive to produce hydrogen rich gas with low CO concentration.