Gold nanocluster sensitized TiO2 nanotube arrays for visible-light driven photoelectrocatalytic removal of antibiotic tetracycline.
It is of technical interest to develop low-cost, high-quality and scalable photosensitizers that could efficiently harvest visible light. Here we design an efficient photoelectrocatalyst by integrating a recently developed gold nanocluster (AuNC, as a photosensitizer) into two types of highly ordered TiO2 nanotube arrays (TNAs, as substrates to host the photosensitizers). The TNA electrodes used in this study are a short TNA (∼0.5 µm in length, synthesized by the anodic oxidation in an aqueous hydrofluoric (HF) acid solution) and a long TNA (∼4.5 µm in length, synthesized by the anodic oxidation in a fluorinated ethylene glycol (EG) solution). A number of characterization techniques (e.g., FESEM, XRD and XPS) were applied to study the as-synthesized nanocomposites. In particular, diffuse reflectance spectroscopy and photochemical measurements suggest that the AuNC-coated TNA electrodes have successfully extended visible light absorption and improved their photochemical performance. Compared with the blank TNAs, the as-designed nanocomposites exhibit an evidently enhanced photoelectrocatalytic performance towards tetracycline (an emerging antibiotic contaminant in aquatic environment) decomposition, where the removal efficiency increases from 65% to 81% for AuNC/long-TNA and from 46% to 73% for AuNC/short-TNA electrodes, respectively. The improved performance is largely attributed to the photo-electro-chemical synergetic effect. The photochemical performance of the as-designed nanocomposites could be further improved by fine tuning the size, composition, and surface of the AuNC-based photosensitizers.
NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-03, 117411 Singapore. eriliuyb@nus.edu.sg.
Yanbiao
Y
Liu
Qiaofeng
Q
Yao
Xuejun
X
Wu
Tiankai
T
Chen
Ying
Y
Ma
Choon Nam
CN
Ong
Jianping
J
Xie
D000900:Anti-Bacterial Agents / Q000302:isolation & purification*; D006046:Gold; D043942:Nanotubes; D013754:Tetracyclines / Q000302:isolation & purification*; D014025:Titanium
D000900:Anti-Bacterial Agents; D013754:Tetracyclines; C009495:titanium dioxide; D006046:Gold; D014025:Titanium