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Rational design of a visible-light photochromic diarylethene: a simple strategy by extending conjugation with electron donating groups
摘要： Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electron donating groups. The modified dirylethene derivative can photocyclolize under 405-nm light with a good photochromic efficiency. Meanwhile, its absorption and moderate fluorescence can be switched effectively in both directions by visible lights (405 and 520 nm, respectively) in different solutions and in living cells. We believe that this simple method will become a versatile strategy for developing various dirylethylenes with visible-light photochromism.
关键词： fluorescence photoswitching,diarylethylenes,photoreaction quantum yield,visible-light photochromism
更新于2025-11-19 16:56:35
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Visible light-driven photoelectrocatalytic degradation of Acid Yellow 17 using Sn3O4 flower-like thin films supported on Ti substrate (Sn3O4/TiO2/Ti)
摘要： This article reports a new method for preparing mixed valence tin oxide (Sn3O4) flower-like nanostructures using a microwave-assisted route. Thin-film Sn3O4/TiO2/Ti electrodes demonstrated highly efficient visible light driven photocatalytic degradation of monoazo acid yellow 17 (AY17) dye, reaching 95% color removal after 60 min at pH 2. Moreover, under low bias potential (0.5 V), the photoelectrocatalytic efficiency increased to 97% color removal and 83% removal of total organic carbon at a kinetic rate almost 3 times higher than in photocatalysis. Liquid chromatography mass spectrometry was used to identify intermediate formation, and oxidation performance was proposed for photocatalytic and photoelectrocatalytic degradation with no organics identified after 120 min of treatment. The results indicate that Sn3O4/TiO2/Ti photoelectrodes offer a simple, green method for wastewater treatment employing visible light source.
关键词： Dye degradation,Photoelectrocatalysis,Microwave-assisted hydrothermal synthesis,Sn3O4,Visible-light photocatalysis
更新于2025-11-19 16:56:35
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A novel photocatalyst, Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3, for highly efficient photocatalytic hydrogen evolution under visible-light irradiation
摘要： In this work, Y2SiO5:Pr3+,Li, as an excellent up-conversion luminescence agent from visible-light to ultraviolet-light, is synthesized by using sol-gel method. And then, a series of Y2SiO5:Pr3+,Li/NaNbxTa1?xO3 (x = 0.00, 0.25 and 0.50) with different amounts of Y2SiO5:Pr3+,Li are prepared by using hydrothermal method. The prepared samples are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV–vis absorption spectroscopy and photoluminescence spectroscopy (PL). The activities of Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3 are investigated through photocatalytic hydrogen evolution in 10 vol% methanol solution under visible-light irradiation. The influences of Nb content in NaNbxTa1?xO3, mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3, visible-light irradiation time and reuse-times are examined on the visible-light photocatalytic hydrogen evolution. The experimental results showed that the prepared Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3 with 0.4:1.0 mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3 and 0.25 wt% Pt loading displayed a highest evolved hydrogen activity under visible-light irradiation. This study may provide some significant references for large scale photocatalytic hydrogen evolution utilizing solar energy.
关键词： Visible-light photocatalyst (Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3),Photocatalytic hydrogen evolution,Pt loading,Nb-substituted NaTaO3,Up-conversion luminescence agent (Y2SiO5:Pr3+,Li)
更新于2025-11-19 16:51:07
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Effects of annealing conditions on the oxygen evolution activity of a BaTaO2N photocatalyst loaded with cobalt species
摘要： Precise engineering of the cocatalyst-photocatalyst interface and optimization of the cocatalyst dispersion are essential for improving the activity of particulate semiconductor photocatalysts. Herein, we report the effects of varying the conditions used to load cobalt oxide (CoOx) as a cocatalyst on the O2 evolution activity of a particulate BaTaO2N photocatalyst, based on trials in an aqueous silver nitrate solution under visible light irradiation. Annealing under an N2 flow after loading the Co species increased the O2 evolution rate threefold compared to that obtained following conventional annealing under an NH3 flow. Subsequent annealing under an H2 atmosphere exposed the BaTaO2N surface as a result of the aggregation of CoOx particles, and further enhanced the photocatalytic O2 evolution by a factor of two, yielding an apparent quantum efficiency of 0.55% at 420 nm. These results indicate the importance of intimate contact between cocatalyst particles and the photocatalyst, as well as the necessity of exposing the photocatalyst surface to make it available for reduction reactions during photocatalytic water oxidation.
关键词： Cocatalyst,Dispersion,Oxynitride,Visible light
更新于2025-11-19 16:51:07
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Distinguishing the effects of altered morphology and size on visible-light-induced water oxidation activity and photoelectrochemical performance of BaTaO2N crystal structures
摘要： Factors, including crystallinity, morphology, size, preferential orientation, growth, composition, porosity, surface area, etc., can directly influence the optical, charge-separation, charge-transfer and water oxidation and reduction properties of particle-based photocatalysts. Therefore, these factors must be considered when designing high-performance particle-based photocatalysts for solar water splitting. Here, a flux growth method was applied to alter the morphology and size of the Ba5Ta4O15 precursor oxide crystals using BaCl2, KCl, RbCl, CsCl, KCl+BaCl2 and K2SO4 at different solute concentrations, and the impact of nitridation with and without KCl flux was studied. Specifically, the effects of altered morphology and size on the visible-light-induced water oxidation activity and photoelectrochemical performance of the BaTaO2N crystal structures were investigated. Upon nitridation, the samples became porous due to the lattice shrinkage caused by the replacement of 3 O2? with 2 N3? in the anionic network. The BaTaO2N crystal structures obtained by nitridation without KCl flux show higher surface areas than do their counterparts prepared by nitridation with KCl flux because of the formation of porous networks. All samples exhibited a high anodic photocurrent upon nitridation without KCl flux compared with that of the samples obtained by nitridation with KCl flux. The findings demonstrate that it is important to specifically engineer photocatalytic crystals to reach their maximum potential in solar water splitting.
关键词： Water splitting,Visible light,Flux growth,Crystal size,Morphology,BaTaO2N
更新于2025-11-19 16:51:07
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Effect of conduction band potential on cocatalyst-free plasmonic H <sub/>2</sub> evolution over Au loaded on Sr <sup>2+</sup> -doped CeO <sub/>2</sub>
摘要： There is little information on the effect of the conduction band (CB) position on plasmonic hydrogen (H2) formation under visible light irradiation over gold (Au) nanoparticles supported on semiconductors because there were no appropriate materials for which the CB position gradually changes. In this study, we analyzed the flatband potential of strontium ion (Sr2+)-doped cerium(IV) oxide (CeO2:Sr) and found that the CB position gradually shifted negatively from +0.031 V to ?1.49 V vs. NHE with an increase in the Sr2+ mole fraction. Plasmonic photocatalysts consisting of Au nanoparticles, CeO2:Sr and a platinum (Pt) cocatalyst were prepared and characterized by using X-ray diffraction, UV-vis spectroscopy, and transmission electron spectroscopy. Photocatalytic reaction under visible light irradiation revealed that H2 was produced over Au nanoparticles supported on CeO2:Sr having the CB potential of ?0.61 V vs. NHE and that the negative limit of the CB position for electron injection from Au nanoparticles existed between ?0.61 V and ?1.49 V vs. NHE. We found that Au/CeO2:Sr plasmonic photocatalysts also produced H2 without the aid of a Pt cocatalyst due to the sufficiently negative potential of electrons injected into the CB of CeO2:Sr.
关键词： hydrogen evolution,visible light irradiation,gold nanoparticles,plasmonic photocatalysts,strontium-doped cerium oxide
更新于2025-11-19 16:51:07
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Self-generating CeVO4 as conductive channel within CeO2/CeVO4/V2O5 to induce Z-scheme-charge-transfer driven photocatalytic degradation coupled with hydrogen production
摘要： The construction of highly efficient Z-scheme photocatalytic system is regarded as a hot research topic in the fields of environmental remediation and renewable energy production. In this work, a novel Z-scheme CeO2/CeVO4/V2O5 photocatalyst is successfully prepared by using solid phase reaction method. The photocatalytic degradation of organic pollutant (Methylene Blue) with simultaneous hydrogen production is efficiently realized over the prepared Z-scheme CeO2/CeVO4/V2O5 photocatalysts under visible-light irradiation. The effects of treatment temperatures and treatment times of CeO2/V2O5 composite on the photocatalytic performance of Z-scheme CeO2/CeVO4/V2O5 photocatalyst are studied. The as-prepared Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst heat-treated at 550 °C for 3.0 h exhibits the highest photocatalytic performance. It can be ascribed to a moderate amount of CeVO4 nanoparticles generated between CeO2 and V2O5. The generated CeVO4 nanoparticles can be used as effective conductive channel to transfer the photo-generated carriers. At the same time, as redox reaction centers it can further accelerate the transfer of photo-generated electrons, effectively enhancing the separation efficiency of photo-generated electron and hole pairs. Furthermore, cyclic test demonstrates that the as-prepared Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst still maintains a high level of photocatalytic activity within five periods under the same conditions. Moreover, the related photocatalytic mechanism for degradation of organic pollutants with simultaneous hydrogen evolution over the Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst is proposed. Perhaps, this study affords a simple and novel method to design and develop next generation of highly efficient Z-scheme photocatalysts.
关键词： Conductive channel,Z-scheme CeO2/CeVO4/V2O5 photocatalyst,Solid phase reaction method,Simultaneous hydrogen evolution,Visible-light photocatalytic degradation
更新于2025-11-19 16:51:07
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Black phosphorous sensitized TiO <sub/>2</sub> mesocrystals photocatalyst for hydrogen evolution with visible and near-infrared light irradiation
摘要： Wide absorption from ultraviolet (UV) to near-infrared (NIR) region and enhanced charge separation are two main requirements for promising semiconductor photocatalysts. Here, we studied visible-NIR driven photocatalytic hydrogen evolution over black phosphorus nanosheets/TiO2 mesocrystals loaded with Pt heterostructure (BP NS/ Pt (3 wt%)/TMC TMC). BP NS/Pt (3 wt%)/TMC can harvest photons from UV to NIR and simultaneously has enhanced charge separation to increase the generation of electrons for photocatalytic reduction of water. BP NS/Pt (3 wt%)/TMC exhibited photocatalytic H2 evolution rates of 1.9 and 0.41 μmol h-1 under visible (λ> 420 nm (420-1800 nm)) and NIR (λ> 780 nm (780-1800 nm) irradiation, respectively, compared with 0.3 and 0.10 μmol h-1 for BP NS/Pt (3 wt%)/P25. Moreover, a comparative study was made to examine the effect of thickness of BP NS on the photocatalytic H2 evolution. Femtosecond time-resolved diffused reflectance spectroscopy (fs-TRDRS) was integrated together with photoelectrochemical measurement to shed the light on the importance of charge transfer and separation, confirming that decreasing the thickness of BP NS enhances electron injection from BP NS to TMC to increase the photocatalytic activity.
关键词： hydrogen evolution,Black phosphorus,visible-light photocatalyst,charge carriers dynamics,TiO2 mesocrystals,femtosecond time-resolved diffuse reflectance
更新于2025-11-19 16:51:07
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Surface decoration of BiOCl with BiVO<sub>4</sub> particles towards enhanced visible-light-driven photocatalytic performance
摘要： BiVO4/BiOCl p-n junctioned photocatalysts were synthesized by surface replacement of pre-synthesized BiOCl with BiVO4 via a hydrothermal route. BiVO4 particles were decorated on the surface of BiOCl, the structures of which were favored of maximizing absorption of visible light. The photocatalytic activity of the heterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) dye under visible light illumination. The results indicated that the composites exhibited superior efficiencies for RhB photodegradation in comparison with pure BiOCl, BiVO4 and BiOCl/BiVO4 with similar compositions. The 30% BiVO4/BiOCl exhibited an optimal photocatalytic activity due to the combinative effects of large visible-light absorbance and carrier separation. Experiments on scavenging active intermediates demonstrated that the enhanced photoactivity was primarily attributed to the formation of p-n junction. An effective built-in electric field was formed by the interface between p-type BiOCl and n-type BiVO4, which promoted the efficient separation of photoinduced electron-hole pairs.
关键词： visible light absorption,BiVO4 decorated BiOCl,surface replacement,heterostructures,charge carrier separation
更新于2025-11-14 17:04:02
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In-situ solid phase thermal transformation of self-assembled melamine phosphotungstates produce efficient visible light photocatalysts
摘要： Visible-light-driven stacked-layer heterogeneous photocatalyst carbonitride/tungstophosphate (TCN) was constructed via in-situ solid-state thermal transformation using melamine phosphotungstate (MPW). The structural, morphological and optical properties of the samples were investigated. Compared to the MPW hybrids and phosphotungstic acid hydrate, the TCN photocatalysts showed excellent visible light photocatalytic activity. During the thermal transformation, the melamine molecules polymerize to form the defective heptazine structure carbonitride attached to the surface of mixed-valence Keggin units. The interfacial POMs anions-p interactions, ligand-to-metal charge transfer and mix-valence organic-POMs structure makes the electrons fully delocalized over the MPW hybrids, and the TCN photocatalysts obtain the extended light absorption. The Keggin units accept and transfer electrons, so the recombination of photogenerated carriers is suppressed. 13TCN-390 obtains the optimal photocatalytic activity, its photocatalytic degradation efficiency of imidacloprid and rate constant k are 6.38 and 13.50 times than that of CN-390, respectively. The enhanced photocatalytic activity arises from the extended light absorption, suppressed photogenerated carriers’ recombination, surface structure defect and suitable band structure. h+ and (cid:1)OH are the main reactive species when the proposed photocatalytic mechanism was done. This study provides a promising construction strategy for polymer/POMs photocatalysts using different organic-POMs hybrids.
关键词： Melamine phosphotungstate,Visible-light-driven photocatalyst,Degradation,Thermal transformation
更新于2025-11-14 17:04:02