HYDROGEN PRODUCTION FROM DRY REFORMING OF METHANE OVER SUPPORTED NiO/CeO2 CATALYST

Abstract

Dry reforming of methane (DRM) for the production of hydrogen rich-syngas is a widely studied research area. In this investigation, a sequence of bulk and supported Nickel/Cerium catalysts of different ratios were synthesised by sol gel method and evaluated for its reaction. These synthesised catalysts were characterised by BET, FE-SEM, XRD, FTIR and Raman spectroscopy. The surface area of bulk catalyst was very low and it was increased after the addition of support. The XRD result showed that, peak of SiO2 which appeared at 2θ of 21.6o was disappeared with increasing loading of catalyst (decreasing loading of support). It indicated, at higher loading of support silicate type species dominate. The place where SiO2 suggested to be present were appeared at 802cm-1, 1102cm-1 and 3430cm-1 wave number on FTIR spectra. The intensity of 3430cm-1 band was low at 20wt%. catalyst loading at which highest conversion of both CH4 and CO2 were achieved. The reaction (DRM) was evaluated by using gas mixtures of CH4, CO2 and N2 (carrier gas) at the ratio of 1:1:2 with the total flow rate of 100ml/min. It was carried out at 700oC temperature and 1 atm pressure. The most active catalyst was found to be Ni0.75Ce0.25 that achieved 93.9% and 89.6% of CO2 and CH4 conversion respectively. The addition of SiO2 supporter improved the conversion of both CH4 and CO2 of all catalysts, which was above 90% for over the period of 4h, but this improvement was more remarked for 20Ni0.75Ce0.25/ SiO2 loading catalyst, where CH4 conversion was 95.38% and CO2 was totally converted. At 20wt.% loading, the yield of H2 was 56.7% and CO was 70% whereas the selectivity of H2 and CO was 60.13% and 72% respectively. Result showed that, MgO supported catalyst achieved only 10.16% and 7.94% of CO2 and CH4 conversion respectively, which is much less than that of SiO2 and Al2O3 supported catalyst. Among the three supporters, silica (SiO2) supported catalysts showed the highest conversion of both CH4 and CO2 than magnesium oxide (MgO) and alumina (γ-Al2O3) supported catalysts of same loading ratio.