Study On The Preparation Of Cu/ZrO₂-GO Composites And Its Catalytic Performance

As the support of Cu-based catalyst, ZrO2 has a very significant advantage, but there are still some problems and shortcomings in the stability and service life, such as a small surface area, existence of a variety of crystal type,the active component is easy to live and so on. Graphene oxide is a new and efficient support of catalyst. The research will study on the preparation method of Cu/ZrO2-GO composite catalyst. In the process,we will take graphite oxide as the first precursor and zirconium dioxide as the second precursor, then a new catalyst support would be synthesised by chemical bonding reaction between the functional groups of the precursors, the Cu/ZrO2-GO complex catalyst will be prepared with the active components of copper was highly fragmented and well bonded with the catalyst support. So it can improve the catalyst activity of Cu base catalyst for the preparation of iminodiacetic acid from diethanolamine dehydrogenation, and improve the dispersion of Cu, increased specific surface area of the support, prolong the service life of the catalyst.Graphite oxide were prepared by Hummers method and the results indicated that temperature on 90℃ is beneficial to the depth oxide of the graphite. Graphite oxide dispersion was prepared by ultrasonic stripping of the freeze-dried graphite oxide. With zirconium oxynitrate as zirconium source, and the ZrO2-GO composite support were prepared by coprecipitation method, hydrothermal method and sol-gel method. The optimal conditions for the preparation of ZrO2-GO composite support use hydrothermal method is that ZrO2:GO is 50:50(wt%), reaction temperature is 170℃and reaction time is 12 h. The ZrO2-GO were prepared by coprecipitation method, using ammonia as precipitant, coprecipitation temperature of 70℃, calcination temperature of 450℃ with high performance. All the ZrO2-GO were characterized by BET, XRD and FT-IR. The results indicated that the ZrO2-GO prepared by hydrothermal method had a better crystallinity, however the sample prepared by coprecipitation method showed the maximum surface area(150.6 m2·g-1).A series of Cu/ZrO2-GO composite materials were prepared by solid state impregnation and characterized by BET, XRD, FT-IR, H2-TPR and the catalytic activity was tested. The results indicated that catalytic performance of Cu/ZrO2-GO were higher than Cu/ZrO2 and Cu/GO, and the composite support prepared by coprecipitation method supported Cu had the largest surface area,but the ZrO2-GO prepared by hydrothermal method supported Cu had a strong interaction between Cu and ZrO2-GO and exhibited the highest catalyst performance, the conversion of diethanolamine reached 56.3%, and the selectivity of iminodiacetic acid was 92.7%. The catalytic performance of Cu/ZrO2-GO is mainly determined by the inter action between Cu and ZrO2-GO and the structure properties of support rather than by the surface area.