| 초록 |
Microporous and mesoporous silicas are combined with nanoparticulate CdS particles to form hybrid photocatalysts that produce H2 from water/ethanol solutions under visible light irradiation. Catalyst structures are characterized by XRD and SEM. All hybrid materials are active photocatalysts for water splitting, and the order of photoactivity is found to be zeolite-Y(k = 6.6 µmol H2 hr-1) ＞ SBA-15(k = 2.7 µmol H2 hr-1) ＞ zeolite L(k = 1.7 µmol H2 hr-1) under the same experimental conditions. Silica cavity size, which determines CdS particle size, and photocatalytic activity are found to be correlated. Photocatalytic activity is seen to decrease under acidic or basic conditions with an associated negative ionic strength effect. In addition, XPS analysis indicates loss of Cd2+ ion from the silicate supports occurs during the course of the photochemical reaction with apparent retention of bound CdS. We are grateful to the Hydrogen Energy R&D Center of the 21st Century Frontier Research and Development Program of the Ministry of Science and Technology of Korea for financial support. |
