One-Pot Fabrication of High Coverage PbS Quantum Dot Nanocrystal-Sensitized Titania Nanotubes for Photoelectrochemical Processes

Abstract

Lead sulfide quantum dot nanocrystal (QDNC) sensitized TiO 2 nanotubes have been fabricated using a simple, wet chemical method that is both time-and cost-effective. A single precursor source containing both Pb and S has been employed, with oleylamine as a linker molecule to synthesize the PbS under an ambient pressure based approach. This approach serves to assemble the QDNCs on a TiO 2 nanotube surface. Surface characterization was performed using electron microscopy, X-ray diffraction, and elemental analysis, indicating the formation of PbS quantum dots along the nanotube walls and intertubular spacing. The optoelectronic, photoelectrochemical, and photocatalytic properties of the composite heterostructure have been characterized using absorbance spectroscopy, electrochemical studies (including efficiency measurements), and methylene blue conversion as a probe. A 24-fold increase in the photocurrent of TiO 2 −PbS heterostructure over bare TiO 2 nanotube has been observed. Electrochemical impedance measurements of the TiO 2 nanotube sample indicate donor density of ∼4.5 × 10 19 cm −3 while TiO 2 /PbS heterostructure shows an n-n photoactive heterojunction with a donor density of ∼2.3 × 10 20 cm −3 . A 12% increase in photocatalytic activity and theoretical estimates suggesting almost 40-fold enhancement toward value-added product synthesis with PbS inclusion are presented.

Interfacial Charge Transport in 1D TiO2 Based Photoelectrodes for Photoelectrochemical Water Splitting

“…In addition, the heterojunction interface causes a negative shift of Fermi level toward CB edge of TiO 2 , indicating the reduced positive charges accumulation and improved H 2 O oxidation kinetics of the photoelectrode. [ 97,98 ]…”

“…In addition, the heterojunction interface causes a negative shift of Fermi level toward CB edge of TiO 2 , indicating the reduced positive charges accumulation and improved H 2 O oxidation kinetics of the photoelectrode. [97,98] Recently, carbon materials/semiconductor hybrid systems for photocatalytic fuel generation have attracted increasing attention due to element earth-abundant and strong covalent induced superior photocorrosion resistance. Graphitic carbon nitride (g-C 3 N 4 ) is deemed as the next generation of photocatalytic semiconductor to achieve high STH efficiency with visible lights illumination.…”

Floating ZnO QDs-Modified TiO2/LLDPE Hybrid Polymer Film for the Effective Photodegradation of Tetracycline under Fluorescent Light Irradiation: Synthesis and Characterisation

“…Many semiconductor QDs have been successfully deposited on TiO 2 that all showed improved photocatalytic activity when compared with pristine TiO 2 . For instance, WO 3-x QDs [ 7 ], SnO 2 QDs [ 8 ], CdSe QDs [ 6 ], and PbS QDs [ 9 ] have been reported to exhibit enhanced photocatalytic properties. However, the photocatalysts’ main drawback is the difficult separation from the water system for their reusability.…”

A Carbon Nanotube–Metal Oxide Hybrid Material for Visible-Blind Flexible UV-Sensor

“…A nanomaterial-based metal oxide semiconductor has been recognized as an alternative to the silicon-based technology due to flexibility and the wide bandgap that can be exploited for UV sensing. Metal oxides can be assembled as a thin film on a wide range of substrates using a cost-effective wet chemical approach [7]. Among the various metal oxides, ZnO, CuO, and TiO 2 are promising metal oxide semiconductors for their chemical stability, low toxicity, and high selectivity [8][9][10].…”