Trimetallic catalyst, prepared by ultrasonic -impregnation method for selective hydrogenation of acetylene: investigation of potassium addition to Fe-Pd/α-Al2O3 catalyst

Trimetallic Fe-Pd-K/α-Al2O3 catalyst by using ultrasonic impregnation method and adding potassium to bimetallic Fe-Pd/α-Al2O3 catalyst was synthesized. The samples were characterized by BET, XRD, TEM, FESEM-EDX, TPR, NH3-TPD and TGA/DTG analysis. It was found that the number of acidic sites and coke deposition on the surface of the trimetallic catalyst decreased by 52% and 62%, respectively and the particle size distribution was more uniformed compared to the bimetallic one. The impregnation time was reduced from 12 to 1 h, compared to traditional method by using the ultrasonic technique. The trimetallic catalyst was applied in selective hydrogenation of acetylene in excess ethylene while the performance improved and resulted in 52% ethylene selectivity and 64% acetylene conversion. The optimal reaction conditions were found to be acetylene concentration of 1.0 V% and temperature of 60 °C. Under optimal conditions; the yield of the trimetallic catalyst was 1.17 times, compared to the commercial one.