Sonochemical synthesis, photocatalytic activity and optical properties of silica coated ZnO nanoparticles

• Published in: Ultrasonics sonochemistry Vol. 19; no. 4; pp. 750 - 755
• Main Authors: Siddiquey, Iqbal Ahmed, Furusawa, Takeshi, Sato, Masahide, Bahadur, Newaz Mohammed, Mahbubul Alam, Md, Suzuki, Noboru
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-07-2012
• Subjects: Catalysis; Nanoparticles - chemistry; Optical Phenomena; Particle Size; Photocatalytic activity; Photochemical Processes; Silica coating; Silicon Dioxide - chemistry; Sol–gel method; Sonication; Sonochemical synthesis; Surface Properties; UV shielding; Zinc Oxide - chemistry; ZnO; Photocatalytic activity; ZnO; Silica coating; UV shielding; Sonochemical synthesis; Sol–gel method
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2011.12.011

► Ultrasound irradiation resulted in a uniform coating of the ZnO nanoparticles with silica. ► Silica coated ZnO nanoparticles showed a significant inhibition of photocatalytic activity. ► The coated ZnO nanoparticles showed excellent UV shielding ability.
In this paper, we report the synthesis of silica coated ZnO nanoparticles by ultrasound irradiation of a mixture of dispersion of ZnO, tetraethoxysilane (TEOS), and ammonia in an ethanol–water solution medium. The silica coating layer formed at the initial TEOS/ZnO loading of 0.8 for 60min ultrasonic irradiation was uniform and extended up to 3nm from the ZnO surface as revealed from HR-TEM images. Silica coated ZnO nanoparticles demonstrated a significant inhibition of photocatalytic activity against photodegradation of methylene blue dye in aqueous solution. The effects of silica coating on the UV blocking property of ZnO nanoparticles were also studied.