Fabrication of visible-light active Fe2O3-GQDs/NF-TiO2 composite film with highly enhanced photoelectrocatalytic performance

Abstract

Visible-light active Fe 2 O 3 -GQDs/NF-TiO 2 composite films were fabricated via 12 sequential electro-deposition and electro-oxidation processes. The prepared photocatalytic 13 films were extensively characterized using scanning electron microscopy (SEM), 14 high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), 15 Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results revealed that 16 graphene quantum dots (GQDs) and -Fe 2 O 3 particles were simultaneously deposited onto 17 the surface of N and F co-doped TiO 2 (NF-TiO 2 ) simply using a graphite sheet instead of a Pt 18 sheet as anode in the electro-deposition process. The NF-TiO 2 substrate obtained by calcining 19 TiO 2 nanotubes (TiO 2 -NTs) in the presence of NH 4 F displayed pyramid shapes with dominant 20 (101) facets. Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy 21 (EIS) and Mott-Schottky (M-S) plots indicated that the generation, separation and transfer of 22 photogenerated charges were greatly enhanced on the novel composite. The photocurrent 23 density of Fe 2 O 3 -GQDs/NF-TiO 2 was 4.2 times that on Fe 2 O 3 /TiO 2 -NTs at 0.5 V vs. Ag/AgCl 24 under visible light irradiation. For the photoelectrocatalytic (PEC) reduction of Cr(VI) using 25 Fe 2 O 3 -GQDs/NF-TiO 2 as photoanode with a Ti sheet as cathode, substantially enhanced 1 activity was achieved due to the combined effect of visible-light-active components (-Fe 2 O 3 2 and NF-TiO 2 ) and excellent electron mediator (GQDs). The calculated reduction rate constant 3 was 7 times that obtained on Fe 2 O 3 /TiO 2 -NTs film. Furthermore, both the long-time 4 photocurrent and cyclic PEC reduction of Cr(VI) indicated good stability of the composite 5 film. 6

pH-sensitive and biocompatible quercetin-loaded GO–PEA–HA carrier improved antitumour efficiency and specificity

“…Compared with GO, GO-PEA-HA retained a lamellar structure and HA was modified with GO. In Figure 3(E), the characteristic crystal structure of Que (columnar) can be observed clearly [40]. Furthermore, the morphologies of GO and GO-PEA-HA/ Que were characterized via TEM, as shown in Figure 4.…”

Preparation of a sunlight-driven TiO2 film with excellent material characterizations and photoelectrocatalytic properties by an eco-friendly manner

“…TiO2 films have been widespread employed as the photocatalyst owing to its non-toxicity, chemical stability and less secondary pollution [1][2][3] . However, low utilization rate of sunlight due to wide band gap (3.2 eV for anatase), low specific surface area and low separation efficiency of electron-hole pairs obviously decreases its photocatalytic activities [4,5] .…”

Ternary Hierarchical Cu7S4/TiO2/CoCr‐LDH Heterostructured Nanorod Arrays with Multiphase Reaction Interfaces for More Efficient Photoelectrochemical Water Splitting

“…As a critical component in the three‐electrode structured PEC cells, plenty of efforts have been made on the semiconductor photoelectrode. Since Fujishima and Honda succeeded in reporting the photoelectrolysis of water using a single‐crystal TiO 2 electrode in 1972 for the first time, till now, multifarious nanostructured semiconductor materials, such as WO 3 , Fe 2 O 3 , ZnO, TiO 2 , and BiVO 4 , have been extensively investigated and selected as candidates in PEC water splitting system due to their significant advantages including low cost, low‐temperature solution fabrication technique, insensitivity of impurities, and high stability under working conditions. However, since the pristine metal oxides normally suffer from wide bandgap, high bulk recombination losses, poor holes transfer efficiency, and sluggish surface oxidation reaction, the exploitation of suitable electrode materials with high light‐to‐electricity conversion efficiency and excellent stability is highly imperative but still quite challenging .…”