Selective Thermal and Photocatalytic Decomposition of Aqueous Hydrazine to Produce H 2 over Ag-Modified TiO 2 Nanomaterial.

An Ag-modified TiO 2 nanomaterial was prepared by a one-pot synthesis method using tetra butyl titanate, silver nitrate, and sodium hydroxide in water at 473 K for 3 h. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to determine the structure and morphology of the synthesized Ag-modified TiO 2 nanomaterial. The diffuse reflectance UV-visible and photoluminescence spectroscopy results revealed that metallic Ag nanoparticles decreased the optical band gap and photoluminescence intensity of the TiO 2 . In addition, the Raman peak intensity and absorbance were increased after Ag modification onto TiO 2 . The photocatalytic efficiency of the synthesized samples was tested for decomposition of aqueous hydrazine solution under visible light irradiation. The photocatalytic efficiency of Ag-modified TiO 2 nanomaterials was higher than that of bare TiO 2 and Ag metal NPs due to the synergistic effect between the Ag metal and TiO 2 structures. In addition, the surface plasmon resonance (SPR) electron transfer from Ag metal particles to the conduction band of TiO 2 is responsible for superior activity of TiO 2 -Ag catalyst. The Ag-modified TiO 2 nanomaterials offered a 100% H 2 selectivity within 30 min of reaction time and an apparent rate constant of 0.018 min -1 with an activation energy of 34.4 kJ/mol under visible light radiation.