Catalytic performance of nickel immobilized on organically modified montmorillonite in the steam reforming of ethanol for hydrogen production

Nickel immobilized on organically modified montmorillonite (Ni/OMt) was prepared by impregnation method and used as the catalyst for hydrogen production from ethanol steam-reforming; the Ni/OMt catalyst was characterized by XRD, FT-IR, H₂-TPR, SEM, XPS and N₂ adsorption-desorption. The results indicate that in comparison with the catalyst of nickel supported on unmodified montmorillonite (Ni/MMT), the Ni/OMt catalyst exhibits higher surface area and pore volume as well as higher nickel dispersion with smaller metallic particle size. For the ethanol steam-reforming over Ni/OMt, the conversion of ethanol keeps at 100%, with a selectivity of 70% to hydrogen during the 30h reaction test at 773K;however, over the unmodified Ni/MMT catalyst, severe carbon deposition is observed after reaction for only 10h, accompanying with catalyst deactivation and the formation of byproducts such as acetaldehyde and ethylene. The modification of MMT with cetyltrimethylammonium bromide (CTAB) can significantly improve the stability of the Ni/OMt catalyst in ethanol steam-reforming and reduce the carbon deposition rate by immobilizing highly dispersed nanoparticle Ni on the interlayers of OMt; the selectivity to ethylene and acetaldehyde is also greatly depressed.