Dry reforming of methane (DRM);
H-2;
productionRh;
WATER-GAS SHIFT;
METAL CRYSTALLITE SIZE;
CARBON-DIOXIDE;
MECHANISTIC ASPECTS;
RU/TIO2;
CATALYSTS;
RHODIUM CATALYSTS;
SYNGAS PRODUCTION;
CO ADSORPTION;
SELECTIVE METHANATION;
NI;
D O I:
10.1016/j.ijhydene.2023.03.114
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The effect of Al2O3, TiO2, ZrO2 and Yttria-Stabilized Zirconia (YSZ) supports on the activity of the dry reforming of CH4 towards syngas production was investigated for Rh and Ru catalysts. Ruthenium-based catalysts were found to generally be more active than Rh leading H-2/CO ratios close to unity above 700 degrees C. Methane conversion turnover frequency (TOF) over Rh catalysts becomes optimum for Rh/YSZ followed by Rh/TiO2 and Rh/ZrO2, and finally Rh/Al2O3, which exhibited the lowest activity. The performance order is different for Ru catalysts, with TOF being increased in the order Ru/Al2O3<Ru/TiO2<Ru/YSZ < Ru/ZrO2. Time-on-stream (TOS) stability tests showed that Rh/ZrO2 is stable for 30 h, whereas Ru/ZrO2 exhibits a slight decrease of both reactants' conversions. DRIFTS studies indicated that the reaction proceeds via a bifunctional mechanism involving both the metal and the support in the reaction pathway. The population and adsorption sites of produced carbonyls are strongly influenced by the metal-support combination determining the catalytic activity.