Abstract: Ba-doped nano-magnesia (Ba-MgO) was prepared by the chemical co-precipitation method using ultrasonic technique, and a Ru catalyst was prepared using this Ba-doped nano-magnesia as the support andRu3(CO)12as the Ru precursor by impregnation. The catalyst was characterized by field-emission scanning electron microscopy,X-raydiffraction, and N2 physical adsorption.The Ba-doped nano-magnesia treated with ultrasonic wave has large surface area and regular porosity, and Ba was uniformly dispersed in the support. The activity of the Ru catalyst for ammonia synthesis was evaluated under the conditions of10000h-1, 10.0 MPa, and400-450℃. With the promotion of Ba, the Ru catalyst supported on Ba-MgO showed high activity. When the nano-magnesia was treated with ultrasonic wave for 30 min, the reaction rate of ammonia synthesis over4%Ru/Ba-MgOreached 61.02 mmol/(g•h) under the conditions of 10.0 MPa, 425 ℃, and10000h-1.

Key words: ultrasonic preparation, barium, nano-magnesia, ruthenium, supported catalyst, ammonia synthesis