TiO₂ Inverse Opals Modified by Ag Nanoparticles: A Synergic Effect of Enhanced Visible-Light Absorption and Efficient Charge Separation for Visible-Light Photocatalysis

• Main Authors: Thanh-Hiep Thi Le, Thanh-Trang Bui, Hao Van Bui, Van-Duong Dao, Loan Le Thi Ngoc
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Catalysts
• Subjects: titanium dioxide; inverse opals; visible-light photocatalysis; rifampicin degradation; charge separation
• Online Access: https://www.mdpi.com/2073-4344/11/7/761

This work reports on the synthesis, characterization, and photocatalytic performance of the TiO₂ inverse opal nanostructure (IP-TiO₂) and the IP-TiO₂ modified by Ag nanoparticles (Ag@IP-TiO₂). The IP-TiO₂ is fabricated using polystyrene spheres as the template and TiCl₄ as the precursor, and the Ag@IP-TiO₂ is realized by photoreduction method. The morphological, structural, and optical properties of the materials are investigated by scanning electron microscopy, X-ray diffraction, ultraviolet–visible (UV-VIS) absorption spectroscopy, and photoluminescence spectroscopy. Their photocatalytic performances are studied by the degradation of rifampicin antibiotic under the visible-light irradiation generated by an LED lamp. The results demonstrate that the IP-TiO₂ is composed of mesopores arranged in the honeycomb structure and strongly absorbs visible light in the wavelength range of 400–500 nm. This facilitates the visible-light catalytic activity of IP-TiO₂, which is further enhanced by the surface modification by Ag nanoparticles. Our studies on the UV-VIS absorption and photoluminescent properties of the materials reveal that the presence of Ag nanoparticles not only enhances the visible-light absorption of IP-TiO₂, but also reduces the recombination of photogenerated electrons and holes. These two factors create a synergic effect that causes the enhanced photocatalytic performance of Ag@IP-TiO₂.