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Solar-driven CO2 reduction to solar fuel is an effective way to deal with the greenhouse effect and energy crisis. A one-step hydrothermal method was used to synthesize Bi4Ti3O12/SrTiO3 composite photocatalysts. The heterogeneous ...
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Solar-driven CO2 reduction to solar fuel is an effective way to deal with the greenhouse effect and energy crisis. A one-step hydrothermal method was used to synthesize Bi4Ti3O12/SrTiO3 composite photocatalysts. The heterogeneous structure formed by intimate contact was observed between SrTiO3 (STO) nanoparticles and Bi4Ti3O12 (BTO) nanoplates, achieving an enhanced photocatalytic CO2 reduction yield of CO (13.37 mu mol/g) that was 5.74-fold that of pure STO (2.33 mu mol/g), with a high yield of CH4 (1.55 mu mol/g). Characterizations of phase composition, morphology, and optical/electrochemical properties were applied to prove the heterojunction structure and its role in improving the photocatalytic performance. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy tests demonstrate that electrons transfer from STO to BTO and result in the generation of an internal electron field between the two phases. Consequently, a direct Z-scheme system was formed: photoelectrons in the conduction band of BTO transferred to the valence band of STO to recombine with the holes thus spatially separated the photogenerated electron-hole pairs while enabling the photocatalyst to achieve the maximum reduction and oxidation capability. The catalyst structure system proposed here may bring new ideas for the development of titanate-based photocatalysts with high CO2 reduction activity. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)
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Heterostructured Bi2Ti2O7/Bi4Ti3O12 nanocomposites were successfully synthesized through a facile calcination method. The composition and band gap of the Bi2Ti2O7/Bi4Ti3O12 nanocomposites were controlled by tuning the calcination ...
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Heterostructured Bi2Ti2O7/Bi4Ti3O12 nanocomposites were successfully synthesized through a facile calcination method. The composition and band gap of the Bi2Ti2O7/Bi4Ti3O12 nanocomposites were controlled by tuning the calcination temperature. The morphology of the Bi2Ti2O7/Bi4Ti3O12 composite changed from worm-like nanosheets to spherical particles when the calcination temperature increased from 500 to 800 degrees C. The structural features of the heterojunction were confirmed using characterization techniques such as XRD, SEM, HRTEM, ESR, and SPV. The Bi2Ti2O7/Bi4Ti3O12 nanocomposite calcined at 600 degrees C had the highest visible light photocatalytic activity, which was almost 2.0 times as high as that of the pure Bi2Ti2O7 for Rhodamine B (RhB) photodegradation, and 2.5 times the rate of 2,4-dichlorophenol (2,4-DCP) removal under simulated sunlight irradiation. The enhanced photocatalytic activity is due to the heterojunction interfaces induced by the match of lattice and energy levels between Bi2Ti2O7 and Bi4Ti3O12, which is helpful for the separation and transfer of electron-hole pairs. The photocatalytic mechanism was elucidated via active species trapping experiments and electron spin resonance. The photogenerated holes played a key role in the degradation reaction via the Bi2Ti2O7/Bi4Ti3O12 composites. Finally, a possible charge transfer mechanism for the enhanced photocatalytic activity was proposed. (C) 2016 Published by Elsevier B.V.
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We have investigated the preparation and properties of Bi4Zr0.5Ti2.5O12 thin films on the LaNiO3 bottom electrode. The Bi4Zr0.5Ti2.5O12 thin films were fabricated on the LaNiO3 bottom electrode using the sol-gel method. The struct...
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We have investigated the preparation and properties of Bi4Zr0.5Ti2.5O12 thin films on the LaNiO3 bottom electrode. The Bi4Zr0.5Ti2.5O12 thin films were fabricated on the LaNiO3 bottom electrode using the sol-gel method. The structure and morphology of the films were characterized using x-ray diffraction and scanning electron microscopy. The results show that the films are a perovskite phase with a dense microstructure. The 2Pr and 2Vc of the Pt/BZT/LaNiO3 capacitor are 28.2 mu C cm(-2) and 14.7 V respectively under the applied voltage of 25 V. After the switching of 1 x 10(10) cycles, the Pr value decreases to 87% of its pre-fatigue values. The dielectric constant and the dielectric loss are about 204 and 0.024 at 1 kHz, respectively. The films show good insulating behaviour according to the test of leakage current.
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Loading a noble metal on Bi 4 Ti 3 O 12 could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons a...
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Loading a noble metal on Bi 4 Ti 3 O 12 could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons and photoholes. In this paper, AgPt/Bi 4 Ti 3 O 12 composite photocatalysts were prepared using the photoreduction method, and the effects of the type and content of noble metal on the photocatalytic performance of the catalysts were investigated. The photocatalytic degradation of rhodamine B (RhB) showed that the loading of AgPt bimetallic nanoparticles significantly improved the catalytic performance of Bi 4 Ti 3 O 12 . When 0.10 wt% noble metal was loaded, the degradation rate for RhB of Ag 0.7 Pt 0.3 /Bi 4 Ti 3 O 12 was 0.027 min ?1 , which was respectively about 2, 1.7 and 3.7 times as that of Ag/Bi 4 Ti 3 O 12 , Pt/Bi 3 Ti 4 O 12 and Bi 4 Ti 3 O 12. The reasons may be attributed as follows: (i) the utilization of visible light was enhanced due to the surface plasmon resonance effect of Ag and Pt in the visible region; (ii) Ag nanoparticles mainly acted as electron acceptors to restrain the recombination of photogenerated electron-hole pairs under visible light irradiation; and (iii) Pt nanoparticles acted as electron cocatalysts to further suppress the recombination of photogenerated electron-hole pairs. The photocatalytic performance of Ag 0.7 Pt 0.3 /Bi 4 Ti 3 O 12 was superior to that of Ag/Bi 4 Ti 3 O 12 and Pt/Bi 3 Ti 4 O 12 owing to the synergistic effect between Ag and Pt nanoparticles.
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Promising mesoporous Bi24O31Br10/SrTiO3 (BOB/STO) nanocomposites were successfully designed and fabricated via a three-step approach. The morphology, structure, optical performance, surface area and pore-size distribution of the p...
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Promising mesoporous Bi24O31Br10/SrTiO3 (BOB/STO) nanocomposites were successfully designed and fabricated via a three-step approach. The morphology, structure, optical performance, surface area and pore-size distribution of the products were characterized by x-ray powder diffraction, x-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, diffuse reflectance spectroscopy and Brunner-Emmett-Teller analysis. The results indicate that BOB/STO nanocomposites are composed of perovskite STO nanoparticles and monoclinic BOB nanosheets. Compared with pure STO nanoparticles or BOB nanosheets, the mesoporous BOB/STO nanocomposites show a much better photocatalytic activity for the removal of methyl orange solution under simulated sunlight irradiation. In particular, the 10% BOB/STO composite is found to be the optimal composite, over which the dye decomposition reaches 95.3% for 100min. The photocatalytic decomposition rate of the 10% BOB/STO nanocomposite is found to be 3.4 and 4.09 times higher than that of bare BOB and STO, respectively. The enhanced photocatalytic performance of the BOB/STO nanocomposites is attributed to the efficient charge separation and reduced recombination probability of photogenerated electron-hole (e(-)-h(+)) pairs. Furthermore, the BOB/STO nanocomposites show the considerable stability and recycling capacity in the reaction process. In addition, the photocatalytic mechanism of the BOB/STO nanocomposites is explained by a plausible Z-scheme heterojunction.
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Bi4Ti3O12 is a tri-layer Aurivillius member compound that was reported to have good photocatalytic properties. Metal element doping and morphological particle tuning are strategies to increase photocatalyst activity. In this resea...
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Bi4Ti3O12 is a tri-layer Aurivillius member compound that was reported to have good photocatalytic properties. Metal element doping and morphological particle tuning are strategies to increase photocatalyst activity. In this research, the compound micro sheets Bi4Ti3O12 and Bi4Ti2.95V0.05O12 were synthesized using molten NaCl/KCl salt. The diffractogram shows that the Bi4Ti3O12 sample was successfully synthesized, however, there are still found impurities at the Bi4Ti2.95V0.05O12 sample. Micrographs showed that the morphology particle samples is. The results of UV-Vis DRS spectra calculation show that both samples have a band gap energy of ~2.97 eV.
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Low-temperature hydrothermal epitaxial growth and topochemical conversion (TC) reactions offer unexploited possibilities for the morphological engineering of heterostructural and non-equilibrium shape (photo)catalyst particles. Th...
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Low-temperature hydrothermal epitaxial growth and topochemical conversion (TC) reactions offer unexploited possibilities for the morphological engineering of heterostructural and non-equilibrium shape (photo)catalyst particles. The hydrothermal epitaxial growth of SrTiO3 on Bi4Ti3O12 platelets is studied as a new route for the formation of novel nanoheterostructural SrTiO3/Bi4Ti3O12 platelets at an intermediate stage or (100)-oriented mesocrystalline SrTiO3 nanoplatelets at the completed stage of the TC reaction. The Bi4Ti3O12 platelets act as a source of Ti(OH)(6)(2-) species and, at the same time, as a substrate for the epitaxial growth of SrTiO3. The dissolution of the Bi4Ti3O12 platelets proceeds faster from the lateral direction, whereas the epitaxial growth of SrTiO3 occurs on both bismuth-oxide-terminated basal surface planes of the Bi(4)Ti(3)O(12 )platelets. In the progress of the TC reaction, the Bi4Ti3O12 platelet is replaced from the lateral ends toward the interior by SrTiO3, while Bi(4)Ti(3)O(12 )is preserved in the core of the heterostructural platelet. Without any support from noble-metal doping or cocatalysts, the SrTiO3/Bi(4)Ti(3)O(12 )platelets show stable and 15 times higher photocatalytic H-2 production (1265 mu mol.g(-1).h(-1); solar-to-hydrogen (STH) efficiency = 0.19%) than commercial SrTiO3 nanopowders (81 mu mol.g(-1).h(-1); STH = 0.012%) in pH-neutral water/methanol solutions. A plausible Z scheme is proposed to describe the charge-transfer mechanism during the photocatalysis.
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? 2022 Elsevier LtdMagnetostriction-piezoelectric composite films present promising application prospects due to the presence of the magnetoelectric effect. In this paper, a sandwich structure Bi4Ti3O12/CoFe2O4/Bi4Ti3O12 composite...
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? 2022 Elsevier LtdMagnetostriction-piezoelectric composite films present promising application prospects due to the presence of the magnetoelectric effect. In this paper, a sandwich structure Bi4Ti3O12/CoFe2O4/Bi4Ti3O12 composite film was prepared in a pulsed laser deposition system. The morphology, EDX, XPS, ferroelectric, piezoelectric, ferromagnetic and magnetoelectric properties were investigated in detail. In the sample, the atomic percentages of Bi, Ti and O elements measured by EDX are 35.373%, 12.824% and 46.578%, respectively. The out-of-plane electric domain structure and the in-plane magnetic domain structure show that BTO and CFO phases have excellent ferroelectricity (Pr = 1.57 μC/cm?2) and ferromagnetism (Mr = 104.83 emu/cc), respectively. The piezoelectric properties are proportional to the ferroelectric properties, so the composite thin films also have good piezoelectric properties (d33max = 192 p.m./v). Moreover, a great magnetoelectric coupling coefficient (～11.95 mV/cm·Oe) was obtained by mechanical strain transfer and interface coupling. By adding a ferroelectric layer to the composite thin film, the clamping effect can be reduced and the coupling between the ferroelectric and the ferromagnetic layers can be increased, providing the experimental basis for the research of magnetoelectric coupling effect.
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Bi~(2)O~(2.7)/Bi~(2)Ti~(2)O~(7)composite photocatalyst films are synthesized by sol–gel dip-coating. The ratio of adding Bi and Ti precursors can be controlled during the preparation process. The phase structure is confirmed by X...
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Bi~(2)O~(2.7)/Bi~(2)Ti~(2)O~(7)composite photocatalyst films are synthesized by sol–gel dip-coating. The ratio of adding Bi and Ti precursors can be controlled during the preparation process. The phase structure is confirmed by X-ray diffraction. The UV–visible diffuse reflectance spectrum shows that the composite catalysts present light absorption in the visible region. The obtained Bi~(2)O~(2.7)/Bi~(2)Ti~(2)O~(7)composite films possess superior photocatalytic degradation of rhodamine B, owing to the visible light response of Bi~(2)O~(2.7)and the separation of photogenerated electrons and holes between the two components. As a result, the Bi~(2)O~(2.7)/Bi~(2)Ti~(2)O~(7)(Bi/Ti?=?1:1) displays the highest photocatalytic activity under visible light or UV light irradiation for the degradation of different organic dyes, including methyl blue, methyl orange and acid orange 7.
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