Synthesis Of Cellulose/CuO Hybrids And Its Mechanism

With the increasing depletion of fossil resources, environmental problem is getting worse, renewable resources have been received more and more attentions. Cellulose, as the most widely distributed and most abundant renewable natural polysaccharides, has broad development prospects. Cellulose-based hybrids have gained more interest for the advantages of low price, environmentally-friendly, biodegradability, biocompatibility, and so on.In this paper, cellulose/CuO hybrids were prepared by ultrasonic-assisted method, hydrothermal method, and microwave-assisted hydrothermal method, respectively. The phase, micro-structure and biological activity of the hybrids were characterized by kinds of methods. In addition, the mechanism of ultrasound and growth mechanism of CuO on the cellulose substrate have also been investigated according to the results of experiments. The results of this paperwere summarized as follows:(1) Experimental results revealed that Cu(OH)2 and CuO crystals were highly aggregated and abounded tightly on the surface of cellulose. The CuO crystals were obtained by thermal transformation of the hybrids in the air atmosphere; meanwhile, the Cu/C hybrids were obtained by thermal transformation of the hybrids in the Ar atmosphere. Cellulose also served as the reduc ing reagent for the formation of Cu/C hybrids. In addition, Cu/C hybrids are important catalysts in methanol decomposition.(2) Experimental results revealed that various reaction parameters including the volume of H2O2, heating method, and pulse mode of ultrasound irradiation have influence on the phase and morphology of cellulose hybrids. The addition of H2O2 played an important role in the shape of cellulose hybrids, further affected on the transformation from Cu(OH)2 to CuO. These results provided indirect evidence on the H2O2-induced oxidation route during the ultrasound irradiation process.(3) In comparison to the hydrothermal method, CuO crystals transformed into Cu2O crystals and CU2O crystals with different shapes and sizes were obtained via the microwave-assisted hydrothermal method. Cellulose acted as matrix and reductant in the reaction system. It is important to explore the influence of different heating methods for further research of the growth process and reaction mechanism of copper oxide crystal.