The Interaction Between Gold Nanoparticles And Biological Macromolecules And Their Applications In Catalysis

Gold nanoparticles have great interest because of their good conductivity, unique optical, electrical, catalytic properties. In this paper, colloidal gold nanoparticles were prepared by chemical reduction method using chitosan and phycoerythrin as stabilizers. The interaction between gold nanoparticles and the biological macromolecules was studied. On the basis, gold catalysts supported on chitosan-modified inorganic oxides were prepared by anionic impregnation. Their catalytic performances for selective liquid oxidation of glucose to gluconic acid were accessed systematically. The techniques such as UVDRS, IR, XRD, TEM, and XPS were employed to characterize the structure of these catalysts. The main results summarize as follows:1. It is first found that chitosan and phycoerythrin is capable of stabilizing gold nanoparticles without aggregation. The size of gold nanoparticles was about 10nm size and well dispersed. It is known that the amino, hydroxyl and other active groups in these biomolecules can bond to gold nanoparticles and form Au-N or Au-O bond, which are accountable for stabilizing gold nanoparticles.2. The amount of chitosan and phycoerythrin has obvious influence on the catalytic performance of gold nanoparticles. It was found that adding proper amount of the stabilizers to colloidal gold nanoparticles can improve the activity of glucose oxidation. But the extra amount of the stabilizers may encapsulate the gold nanoparticles and has disadvantage for the activity.3. There is stronger interaction between gold nanoparticles with chitosan. Chitosan can capture gold nanoparticles and form Au@CHI composite material.4. The composite supports of SiO2, Al2O3, TiO2 and AC modified by chitosan were prepared. Gold catalysts supported on these composite supports have better activity for glucose selective oxidation than single supported gold catalysts. The activity order is Au@CHI-SiO2 > Au@CHI-TiO2 > Au@CHI-Al2O3 ~ Au@CHI-AC When molar ratio of glucose/gold is 1000:1, flow velocity of air is 600mL/min and reaction temperature is 70℃, glucose conversion can achieve 44.8% for Au@CHI-SiO2 catalyst.