POTENTIAL OF ZEOLITE-SUPPORTED RHODIUM CATALYSTS FOR THE CO2 REFORMING OF CH4

Zeolite Y supported rhodium catalysts were prepared by ion-exchange st arting from an aqueous solution of [Rh[(NH3)(5)Cl]Cl-2 . 6H(2)0]. Prev ious work in this laboratory had shown that this procedure results in a Ph dispersion of near 100%. The catalysts were tested for their acti vity in the CO2 reforming of CH4. They were found to combine extraordi nary stability with high activity and selectivity. At 923 K, 90 mol-% of the CH4 was converted giving a H-2/CO ratio near unity. A weight lo ading of 0.5 to 0.93% Ph gives the highest turnover frequencies. Therm odynamic equilibrium is reached near 873 K. With a given Ph loading, t he zeolite supports are superior to amorphous supports and NaY is supe rior to the HY. No deactivation was observed in tests of 30 h time on stream at atmospheric pressure or after repeated thermal cycles. No co ke deposition was detected by temperature programmed oxidation of used catalysts. Temperature programmed reduction indicates the presence of three discernible Ph species.