AN ALKALI-PROMOTED RUTHENIUM CATALYST FOR THE SYNTHESIS OF AMMONIA, SUPPORTED ON THERMALLY MODIFIED ACTIVE-CARBON

Ruthenium catalysts deposited on active carbon and pre-calcined at 190 0 degrees C in He atmosphere were studied. The precursors of the activ e phase were RuCl3 . 0.5H(2)O and Ru-3(CO)(12). Potassium and cesium ( hydroxides or nitrates) were used as promoters. The catalysts were cha racterized by TEM, WAXS and H-2 chemisorption. Activity measurements i n NH3 synthesis were performed in a flow integral reactor under a pres sure of 10 MPa at 470, 430, and 400 degrees C (H-2 : N-2 = 3 : 1). It has been found that the alkali-promoted catalyst deposited on the ther mally modified carbon is much more active than that based on untreated carbon. The form of the Ru precursor used in the manufacture of the K -promoted catalyst had no effect on its dispersion or activity. The pr omoting effect of potassium was comparable to that of cesium. A monoto nous increase in the activity of alkali-promoted catalyst vs. Ru conte nt (5-15%) was observed, accompanied by a decrease in dispersion.