Synthesis of Ag/TiO₂ Nanotube Heterojunction with Improved Visible-Light Photocatalytic Performance Inspired by Bioadhesion

Abstract

Inspired by the bioadhesion mechanism found in mussel, a catechol derivative, 3-(3,4-dihydroxyphenyl)propionic acid (diHPP), is employed as both linker and reducer of Ag + to synthesize the Ag/TiO 2 nanotube (Ag/TNT) heterojunction under ambient conditions in this study. In the prepared Ag/TNT composite, Ag nanocrystals about 3.8 nm in diameter distribute over the TNT surface uniformly and form the heterojunction structure with TNT. The diHPP first links to the TNT surface through the bidentate chelation of catechol group with Ti 4+ and then acts as both an anchor and a reducer to in situ nucleate and grow Ag nanocrystals on the TNT surface. By adjusting the AgNO 3 concentration, the loading amount of Ag nanocrystals on the TNT surface can be controlled easily, and the visible-light absorption ability of Ag/TNT heterojunctions enhances with increasing the Ag loading amount. Moreover, their photocatalytic activity was evaluated by the degradation capability of Rhodamine B (RhB) under visible light. The Ag/ TNT heterojunctions exhibit the high visible-light photocatalytic activity, which can almost degrade 100% RhB within 2 h. This excellent performance can be attributed to the local electric field caused by the surface plasmon resonance (SPR) of Ag nanocrystals and the high adsorption capability of TNTs with large specific surface area.

Recent Progress on Titanium Dioxide Nanomaterials for Photocatalytic Applications

“…His Ph.D. work was devoted to the synthesis and characterization of silicon-and boron-based 1D nanostructures (nanotubes, nanowires, and nanocables). [32] In addition, TiO 2 has al arge band gap (E g > 3.2 eV), and it can only be excited by ultraviolet light with aw avelength below 388 nm (equivalent to less than 7% of solar light). His research included the fabrication of nanomaterials (nanoparticles and nanowires), their organization, and their nanomanipulation for applications in different fields such as photovoltaics, robotics, chemical sensing, and biosensing.…”

THE FABRICATION OF Ag NANOPARTICLES LOADED TiO2 NANOTUBES BY PHOTOREDUCTION METHOD AND THEIR PHOTOCATALYTIC ACTIVITY

“…These results show the similarity with some recent study results, which fabricated Ag/TNTs combination materials by different methods in ref. [2,9,12]. The stability of this morphology also exists after 36-hour photoreduction (Fig.…”

“…Then, these electrons will interact with absorped oxygen to create ·O 2 . These ·O 2 make an oxidation creation with MB solution [11,12,14]. The influence of annealing temperature on the photocatalytic ability of Ag/TNTs is presented on Fig.…”

Fast diffusion of silver in TiO2 nanotube arrays

“…The HRTEM image shown in Fig. 7 depicts the characteristic lattice fringe of 3.52 Å for TiO 2 nanotubes and 2.36 Å for Ag, which correspond to the (101) plane of anatase TiO 2 and {111} planes of face-centered cubic (fcc) structure of Ag [33], respectively. The Ag nanoparticles are Ag nanocrystals.…”