Low Temperature Preparation and Photo-Absorbance Property of Micron Size Cu/Nano-TiO_2 Composite Particles

Micron size Cu/nano-TiO2 composite particles were prepared in ambient conditions by bio-inspired method.The surfaces of Cu particles were modified by a kind of amine,and the analysis of XPS indicated that the functional layer containing NH2 and OH groups was formed on the surface of Cu particles through the coordination of nitrogen in the amine to Cu2+.Comparative experiment confirmed that NH2 and OH groups induced the bio-mineralization of nano-TiO2 on the Cu surfaces.XRD result showed that TiO2 of anatase type was deposited on the surfaces of Cu particles.Results of diffuse reflectance spectra(DRS) showed that a weak Absorption at 716.5nm occurred after Cu particles were modified by the amine,which indicated the coordination of N to Cu2+.The photo-Absorbance of Cu/nano-TiO2 composite particles was between the photo-Absorbance of TiO2 and that of Cu.The optical Absorption edge of the particles was extended from 397.5nm to about 448.9nm after Cu loading,because Cu loading introduces new mid gap level below the conduction band of TiO2,and in this way the electron can be excited by visible light through the level.The Absorption edge at 448.9nm indicated that Cu/nano-TiO2 composite particles had the visible light catalytic activity.