Structural, textural and photocatalytic properties of quantum-sized In2S3-sensitized Ti-MCM-41 prepared by ion-exchange and sulfidation methods

In2S3 nanocrystallites were successfully encapsulated into the mesopores of Ti-MCM-41 by a two-step method involving ion-exchange and sulfidation. The X-ray diffraction (XRD) patterns, UV-vis absorption spectra (UV-Vis), high-resolution transmission electron microscopy (HRTEM) and N-2 adsorption-desorption isotherms were used to characterize the structure of the composite materials. It is found that the diameter of most In2S3 nanocrystallites is about 2.5 nm, less than the pore size of Ti-MCM-41. The In2S3 nanocrystallites inside the Ti-MCM-41 host show a significant blue-shift in the UV-vis absorption spectra. Under irradiation of visible light (lambda > 430 nm), the composite material has much higher photocatalytic activity for hydrogen evolution than bulk In2S3. It can be explained by the effective charge-separation in the quantum-sized In2S3-sensitized Ti-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.