Study of coking and catalyst stability over CaO promoted Ni-based MCF synthesized by different methods for CH4/CO2 reforming reaction

摘要

CaO doped Ni/MCF catalysts were prepared by conventional incipient wetness impregnation and sol-gel methods for the study of methane dry reforming reaction. The fresh and used catalysts were characterized using H-2 temperature programmed reduction (H-2-TPR), X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC) and O-2 temperature-programmed oxidation (O-2-TPO). XRD exhibited that CaO and Ni particles are dispersed on the surface of catalyst. The Ni:CaO ratio was adjusted for the improvement of pore textural properties on behalf of enhancement of metal particle dispersion for increased catalytic performance and anti coking. The catalytic performance and stability of the catalysts for methane dry reforming reaction were studied at 700-750 degrees C at atmospheric pressure with GHSV of 24000 mL g(-1) h(-1) having same feed ratio of CH4:CO2 = 1. Experimental results exhibited that catalyst prepared by a sol-gel method showed superior catalytic activity, stability and resisted carbon deposition than catalyst prepared incipient wetness impregnation method. Among all tested catalysts 9CaO 9Ni/MCF catalyst remained the best for catalytic performance and anti-coking activity due to higher metal dispersion with small metal particles, as well as the synergetic effect between CaO and Ni. During 75 h stability test over the catalyst 9CaO 9Ni/MCF the CH4 and CO2 conversion remained 91% and 99% respectively. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.