| Summary: | Photoreduction of Cu<sup>2+</sup> ions to Cu metal by titanium(IV) oxide (TiO<sub>2</sub>) was conducted in the presence of a silica–surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2<i>p</i><sub>1/2</sub> and 2<i>p</i><sub>3/2</sub> in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer–Emmett–Teller specific surface area from 36 and 45 m<sup>2</sup>/g for the silica–surfactant and TiO<sub>2</sub>, respectively, to 591 m<sup>2</sup>/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier–transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO<sub>2</sub> was used solely. Therefore, this study indicated that the photoreduction of Cu<sup>2+</sup> ions to Cu metal by TiO<sub>2</sub> was facilitated under the sulfuric acid medium, where the surfactants extracted from silica–surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO<sub>2</sub>. Thus, this study presents a new application of the conversion of a silica–surfactant hybrid into mesoporous silicas.
|
|---|