Catalytic feature of Ni/MgO catalyst for CO2 reforming of methane under pressurized condition

The Ni/MgO-AN catalyst, prepared by loading of Ni onto nano-magnesia (MgO-AN) obtained from thermal processing of a Mg(OH)(2) alcogel, Was used for CO) reforming of methane under different pressures (0. 1 similar to 2. 0 MPa). The catalyst exhibited high and stable activity under atmospheric pressure. However, the catalyst activity declined with increasing reaction pressure. Thermogravimetry, X-ray diffraction and temperature- programmed hydrogenation (TPH) characterization results showed that carbon deposition was very little on the catalyst reacted under atmospheric pressure. In contrast, serious carbon deposition was found on the catalyst reacted under 1. 0 similar to 2. 0 MPa. The amount of carbon deposits increased with the reaction time up to 12 h when it became stabilized, indicating a self -stabilization feature of the working catalyst at the high pressures. No significant sintering of metallic nickel was detected on the used catalyst in the reaction under atmospheric pressure whereas marked sintering happened in the high-pressure reaction. The carbon deposits on the catalyst used in the atmospheric pressure reaction appeared as a single peak on the TPH profile, but two peaks were observed for the samples used in the high-pressure reaction. These results demonstrate that the catalytic performance of Ni/MgO-AN was different under atmospheric and high pressures.