复频超声法制备合成甲醇铜基催化剂

研究了复频超声共沉淀技术制备Cu／Zn／A1／Zr甲醇合成催化剂及其对催化活性的影响。实验结果表明,采用频率为40,23.8 kHz复频超声技术制备的Cu／Zn／Al／Zr甲醇合成催化剂与普通共沉淀法制备的催化剂相比,其空时收率可提高34％。XRD和FE-SEM等表征结果表明,复频超声共沉淀法制备的催化剂可改变催化剂前体的物相,Cu,Zn组分彼此分散均匀,表现为氧化态催化剂的XRD谱图中各特征峰较为弥散。与单频超声相比,采用复频超声技术可进一步减小催化剂颗粒粒径,增加Cu与Zn组分间的分散程度,这表明复频超声技术有明显的协同作用。

Copper-Based Catalyst for Methanol Synthesis Prepared with Dual-Frequency Ultrasonic Technology

The Cu/Zn/Al/Zr catalysts for methanol synthesis were prepared with three methods: dual-frequency ultrasonic co - precipitation (DFUCP), single - frequency ultrasonic co - precipitation (SFUCP),and non-ultrasonic co-precipitation (NUCP).The space-time yield (STY) of methanol on catalyst prepared by DFUCP was 34 % higher than on catalyst prepared by NUCP under reaction conditions of 250 ℃ , 5.0 MPa and 7 200 h-1 . Results of XRD and FE - SEM showed that precursor phases of catalysts prepared by DFUCP or SFUCP were different from that by NUCP. The former formed a phase where the two components,Zn and Cu, mutually and uniformly dispersed, so the X - ray diffraction lines of unreduced catalysts became weaker and broader than that prepared by NUCP. Comparing with SFUCP, DFUCP made the particle size of catalyst smaller, and components, Zn and Cu dispersed more uniformly in the catalyst. The dual - frequency ultrasonic technology imposed adopted in co- precipitation produced significant synergetic effect on the two components, Zn and Cu.