Potential of zeolite supported rhodium catalysts for the CO2 reforming of CH4 Original Research Article

Zeolite Y supported rhodium catalysts were prepared by ion-exchange starting from an aqueous solution of [Rh[(NH3)5Cl]Cl2·6H20]. Previous work in this laboratory had shown that this procedure results in a Rh dispersion of near 100%. The catalysts were tested for their activity in the CO2 reforming of CH4. They were found to combine extraordinary stability with high activity and selectivity. At 923 K, 90 mol-% of the CH4 was converted giving a H2CO ratio near unity. A weight loading of 0.5 to 0.93% Rh gives the highest turnover frequencies. Thermodynamic equilibrium is reached near 873 K. With a given Rh loading, the zeolite supports are superior to amorphous supports and NaY is superior to the HY. No deactivation was observed in tests of 30 h time on stream at atmospheric pressure or after repeated thermal cycles. No coke deposition was detected by temperature programmed oxidation of used catalysts. Temperature programmed reduction indicates the presence of three discernible Rh species.