| Catalysts prepared from some copper intermetallic compounds, RCu(,2) (R = Th, La, Ce, Pr, Ho), were evaluated for the synthesis of methanol from CO + H(,2). These catalysts were formed by decomposing the intermetallic compounds yielding R oxide and Cu. Activities were measured at 50 atm. using a recirculating reactor and found to be greater than or equal to the CO conversion activity per unit surface area of a traditional coprecipitated CuO-ZnO catalyst. The ThCu(,2)-derived catalyst showed a methanol selectivity similar to the CuO-ZnO catalyst while the other catalysts showed a significant ethanol and higher alcohol production. A positive correlation between methanol activity and carbon monoxide chemisorption uptakes was observed.; Specific activities for the Fischer-Tropsch and methanation reactions of catalysts prepared from the oxidation of ThNi(,5-x)Fe(,x) and CeNi(,5-x)Co(,x) (x = 0,1,2,3,4,5) intermetallic compounds were determined in a differential microreactor at one atm. X-ray diffraction and thermomagnetic analysis indicated that these catalysts are composed of binary alloy particles of the transition metals and ThO(,2) or CeO(,2). Thus this is a novel method of preparing alloy catalysts. Trends in activity, product distribution, CO chemisorption uptake, total surface area, and surface composition were examined for each series. For the ThNi(,5-x)Fe(,x) series the ThNi(,5)-derived catalyst showed the highest activity for both CO conversion and methanation and also yielded the largest percentage of higher hydrocarbons. Conversely, the ThFe(,5)-derived catalyst was the least active and produced only methane as the hydrocarbon product. The alloy catalysts showed activities and selectivities which were intermediate. Preferential surface enrichment of the alloy particles with iron was observed. Surface areas and CO chemisorption uptakes decreased as the other transition metal was introduced into the ThNi(,5) or ThFe(,5). The CeNi(,5-x)Co(,x) series of catalysts showed alloy catalysis behavior. This was illustrated by comparing the actual product distributions to calculated ones using an information theory approach. A maximum in C(,3) production occurred for the CeNi(,5-x)Co(,x) series at x = 2. The CeNi(,5)-derived catalyst showed the highest CO conversion activity for this set.; Finally, catalysts prepared from Ce(,7)Pd(,3) and Ce(,7)Ni(,3) were evaluated for synthesis gas conversion at one atmosphere. Both intermetallic-derived catalysts showed activities higher than their respective metal conventionally supported on SiO(,2) or on Al(,2)O(,3). |
