FeO_x Derived from an Iron-Containing Polyoxometalate Boosting the Photocatalytic Water Oxidation Activity of Ti³⁺-Doped TiO₂

Abstract

The development of efficient and stable catalyst systems using low-cost, abundant, and nontoxic materials is the primary demand for photocatalytic water oxidation. Distinguishing the true active species in a heterogeneous catalytic system is important for construction of efficient catalytic systems. Herein, hydrothermally synthesized Ti3+ self-doped TiO2, labeled as Ti3+/TiO2, was first used as a light absorber in a powder visible light-driven photocatalytic water oxidation reaction. When an iron-containing polyoxometalate Na27[Fe11(H2O)14(OH)2(W3O10)2(α-SbW9O33)6] (Fe11) was used as a cocatalyst, an amorphous layer of active species was wrapped outside the initial Ti3+/TiO2 nanorod and the in situ formed composite was labeled as F/Ti3+/TiO2. When the composite F/Ti3+/TiO2 was tested as a photocatalytic water oxidation catalyst, dramatically improved oxygen evolution performance was achieved. The composite F/Ti3+/TiO2 showed an oxygen evolution rate of 410 μmol/g/h, which was about 11-fold higher than that of prism Ti3+/TiO2. After 24 h of illumination, an O2 yield of 36.4% was achieved. The contrast experiments, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy characterization demonstrated that FeO x is the true cocatalyst that enhanced the oxygen evolution activity of TiO2. A recycling experiment proved that the composite F/Ti3+/TiO2 has favorable stability in the oxygen production process.

Photocatalytic Production of Vanillin over CeOx and ZrO2 Modified Biomass-Templated Titania

“…In all cases, a clear formation of titania structure can be observed, with the presence of two crystalline phases, namely anatase and rutile . In particular, peaks located at 25.0°, 37.6°, 47.9°, 53.9°, 54.8°, 62.4°, and 75.6° could be attributed to (101), (004), (200), (105), (211), (204), and (215) planes of anatase crystal structure. , Moreover, contributions at 27.7°, 36.0°, 40.3°, 57.8°, and 70.2° could be associated to (110), (101), (111), (211), (220), (301) crystallographic signals of rutile. , Even if certain amorphization effects could be observed by the incorporation of the CeO x and ZrO 2 entities, no significant variations were observed in the XRD patterns of the samples, thus preserving the titania nanostructure with the mixture of anatase and rutile components (Table ). Size, microstrain, and cell parameters were evaluated with X-ray diffraction (XRD) using the Williamson–Hall formalism .…”

“…45,46 Moreover, contributions at 27.7°, 36.0°, 40.3°, 57.8°, and 70.2°could be associated to (110), (101), (111), (211), (220), (301) crystallographic signals of rutile. 51,52 Even if certain amorphization effects could be observed by the incorporation of the CeO x and ZrO 2 entities, no significant variations were observed in the XRD patterns of the samples, thus preserving the titania nanostructure with the mixture of anatase and rutile components (Table 1). Size, microstrain, and cell parameters were evaluated with X-ray diffraction (XRD) using the Williamson−Hall formalism.…”

Carbon Quantum Dot Conjugated Copper(II) Phthalocyanine Integrating BiVO4 Semiconductor for Photocatalytic Water Oxidation

“…The steady-state PL spectra of BiVO 4 , BiVO 4 /CQDs, BiVO 4 /CQDs/CuPc-10, and BiVO 4 /CQDs/ZnPc-10 were carried out under the excitation wavelength of 398 nm (Figure c). Compared to other samples, the great reduction of the PL intensity for BiVO 4 /CQDs/CuPc-10 reveals highly efficient charge carrier separation. − The above results all confirm the fast electron transfer rate and high electron–hole pair separation efficiency in BiVO 4 /CQDs/CuPc-10 composites, which will lead to a high photocatalytic activity.…”

Immobilization of Metal–Organic Framework MIL-100(Fe) on the Surface of BiVO4: A New Platform for Enhanced Visible-Light-Driven Water Oxidation

“…The lifetime increase of MIL-100­(Fe)@BiVO 4 manifests that loading MIL-100­(Fe) on the surface of BiVO 4 can effectively promote the separation of photoexcited electron–hole pairs in MIL-100­(Fe)@BiVO 4 . The promoted photoinduced electron and hole separation should be an important parameter, thus leading to the remarkable catalytic water oxidation activity for MIL-100­(Fe)@BiVO 4 . − …”