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Facile Construction of Defect-rich Rhenium Disulfide/Graphite Carbon Nitride Heterojunction via Electrostatic Assembly for fast Charge Separation and Photoactivity Enhancement
摘要： Graphite carbon nitride (CN) is one of the most researched visible light photocatalysts, but it still cannot be used practically because of its low photoactivity resulting mainly from rapid photogenerated charge recombination. To accelerate charge separation, CN was herein electrostatically assembled with ReS2, a two-dimensional semiconductor to construct heterojunction for the first time. The electrostatic and coordination interactions between CN and defect-rich ReS2 make them close contact to form heterojunctions. The ReS2/CN heterojunction exhibits higher photocatalytic performance in pollutant degradation owing to faster generation of reactive oxygen species than CN, as well as increased visible and near-infrared light absorption because of strong photoabsorption of defect-rich ReS2. The accelerated reactive oxygen species generation for the heterojunction arises from accelerated charge separation, especially fast transfer of holes from CN to ReS2 in assistance of interfacial electric field and great valance-band edge difference. This work provides a novel CN-based heterojunction for photoactivity improvement and illustrates significance of electrostatic attraction in fabricating heterojunctions.
关键词： electrostatic interaction,photocatalytic,rhenium disulfide,graphite carbon nitride,charge separation
更新于2025-11-21 11:03:13
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Competing photochemical reactions of bis-naphthols and their photoinduced antiproliferative activity
摘要： Photophysical properties and photochemical reactivity for a series of bis-naphthols 4a-4e and bis-anthrols 5a and 5e were investigated by preparative irradiations in CH3OH, fluorescence spectroscopy and laser flash photolysis (LFP). Methanolysis taking place via photodehydration (bis-naphthols ΦR = 0.04-0.05) is in competition with symmetry breaking charge separation (SB-CS). The SB-CS gives rise to radical ions that were for 4a and 4e detected by LFP. Photodehydration gives quinone methides (QMs) that were also detected by LFP (λmax = 350 nm, τ ≈ 1-2 ms). In the aqueous solvent, excited state proton transfer (ESPT) competes with the above mentioned processes, giving rise to naphtholates, but the process is inefficient and can only be observed in the buffered aqueous solution at pH >7. Since the dehydration of bis-naphthols delivers QMs, their potential antiproliferative activity was investigated by MTT test on three human cancer cell lines (NCI-H1299, lung carcinoma; MCF-7, breast adenocarcinoma; and SUM159, pleomorphic breast carcinoma). Cells were treated with 4 or 5 with or without irradiation (350 nm). An enhancement of the activity (up to 10-fold) was observed upon irradiation, which may be associated to the QM formation. However, these QMs do not cross-link DNA. The activity is most likely associated to the alkylation of proteins present in the cell cytoplasm, as evidenced by photoinduced alkylation of bovine and human serum albumins by 4a.
关键词： quinone methides,bis-anthrols,excited state proton transfer,protein alkylation,bis-naphthols,antiproliferative activity,photodehydration,symmetry breaking charge separation
更新于2025-11-14 15:32:45
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Facile synthesis of indium hydroxide nanosheet/bismuth molybdate hierarchical microsphere heterojunction with enhanced photocatalytic performance
摘要： Various Bi2MoO6 (BM)-based heterojunctions have been constructed to enhance the photocatalytic performance, but hydroxide/BM heterojunctions were rarely reported. To illustrate function of hydroxides in the heterojunctions for charge separation and photoactivity enhancement, In(OH)3/BM heterojunctions were simply prepared for the first time via in situ growth of In(OH)3 nanosheets on surfaces of BM hierarchical microspheres in a chemical precipitation process at the room temperature. Construction of the heterojunction benefits from formation of In-O-Bi/Mo bonds at the interface between BM and In(OH)3. Photoluminescence spectroscopy, time-resolved fluorescence spectroscopy, and photoelectrochemical tests demonstrate that the In(OH)3/BM heterojunction exhibits considerably accelerated separation of photoinduced charge carriers which results in increased generation rates of reactive oxygen species and enhanced photocatalytic degradation efficiencies for Rhodamine B, salicylic acid, and resorcinol, in comparison with pure BM. The heterojunction shows high chemical stability and satisfactory recyclability. This work provides a new BM-based heterojunction and, more importantly, deep insight into function of hydroxides in the heterojunction, which can direct preparation of other hydroxide-containing heterojunctions.
关键词： Bi2MoO6,In(OH)3,Heterojunction,Photocatalysis,Charge separation
更新于2025-11-14 15:24:45
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Enabling low voltage losses and high photocurrent in fullerene-free organic photovoltaics
摘要： Despite significant development recently, improving the power conversion efficiency of organic photovoltaics (OPVs) is still an ongoing challenge to overcome. One of the prerequisites to achieving this goal is to enable efficient charge separation and small voltage losses at the same time. In this work, a facile synthetic strategy is reported, where optoelectronic properties are delicately tuned by the introduction of electron-deficient-core-based fused structure into non-fullerene acceptors. Both devices exhibited a low voltage loss of 0.57 V and high short-circuit current density of 22.0 mA cm?2, resulting in high power conversion efficiencies of over 13.4%. These unconventional electron-deficient-core-based non-fullerene acceptors with near-infrared absorption lead to low non-radiative recombination losses in the resulting organic photovoltaics, contributing to a certified high power conversion efficiency of 12.6%.
关键词： non-fullerene acceptors,power conversion efficiency,voltage losses,charge separation,organic photovoltaics
更新于2025-11-14 15:18:02
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Efficient visible light driven degradation of sulfamethazine and tetracycline by salicylic acid modified polymeric carbon nitride via charge transfer
摘要： Photocatalysis has been widely studied as a promising technique for removal of organic pollutants in wastewater. A modified carbon nitride has been designed for this purpose. In this study, a facile method to synthesize distorted carbon nitride by simply copolymerizing urea and salicylic acid (SA) has been explored. The incorporation of SA induced the structure change from planar structure to distorted curls structure. Compared to pristine CN, the CN-SA shows wide light absorption, which is attributed to the n → π* transition at the nitrogen atoms with lone pair electrons of heptazine units. The photoelectrode of CN-SA exhibited higher photocurrent and lower charge resistance than that of pristine CN electrode, indicating that the photogenerated charge carriers of CN-SA are more efficiently separated. As a result, the optimal CN-SA shows 2-fold enhancement in degradation of tetracycline (TC) as compared to pristine CN. Furthermore, we found that the degradation rate of sulfamethazine (SMZ) was 0.0823 min?1 using the CN-SA photocatalyst, which is three times higher than that of pristine CN (0.0293 min?1). In addition, the CN-SA shows good stability without structural change or loss of photocatalytic performance after four cycles. According to the radical species trapping experiments and electron spin resonance analyses, ?O2? and h+ were the main active species involved in the degradation of organic pollutants. The developed strategy provides a novel approach to design the tunable band structure of organic semiconductor materials for various applications.
关键词： Salicylic acid,Photocatalysis degradation,Carbon nitride,Charge separation,Antibiotics
更新于2025-11-14 14:48:53
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Three-in-one oxygen vacancy: whole visible-spectrum absorption, efficient charge separation and surface site activation for robust CO2 photoreduction
摘要： Exploitation of efficient catalysts to realize solar-driven conversion of inert CO2 into useful fuels confronts big challenges owing to the poor photoabsorption, sluggish charge separation and inefficient surface reactive sites of photocatalysts. Herein, we report a facile and controllable in situ reduction strategy to create surface oxygen vacancies (OVs) on Aurivillius-phase Sr2Bi2Nb2TiO12 nanosheets. Sr2Bi2Nb2TiO12 nanosheets are for the first time prepared by a mineralizer-assisted soft-chemical method, and the introduction of OVs on the surface of Sr2Bi2Nb2TiO12 not only extends photo-response region, but also tremendously promotes separation of photo-induced charge carriers. Moreover, the adsorption and activation of CO2 molecules on the surface of the catalyst are largely enhanced. In the gas-solid reaction system without any co-catalysts or sacrificial agents, OVs-abundant Sr2Bi2Nb2TiO12 nanosheets show an outstanding CO2 photoreduction activity in producing CO with a rate of 17.11 μmol g?1 h?1, ~58 times higher than that of the bulk counterpart, surpassing most previously reported state-of-the-art photocatalysts. Our study provides a three-in-one integrated solution to advance the comprehensive performance of photocatalysts for solar-energy conversion and generation of renewable energy.
关键词： Sr2Bi2Nb2TiO12 nanosheets,charge separation,photocatalytic CO2 reduction,oxygen vacancies
更新于2025-09-23 15:23:52
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Interfacial engineering of Fe2O3@BOC heterojunction for efficient detoxification of toxic metal and dye under visible light illumination
摘要： Recent developments of small band gap semiconductor coupled bismuth carbonate (BOC) heterojunction are advantageous for photocatalysis application because of their improved solar harvesting ability and enhanced charge-carrier collection. In this work, we have developed iron (III) oxide decorated bismuth carbonate (Fe2O3@BOC) heterojunction via a simple two-step process. The developed heterojunction exhibits excellent photocatalytic activity towards reduction of carcinogenic and mutagenic Cr(VI) to nontoxic Cr(III) and degradation of toxic dye [methylene blue (MB)] under visible light illumination. Further investigation revealed that the loading of Fe2O3 nanoparticles had an impact on efficient charge carrier collection at the interface of Fe2O3@BOC heterojunctions. The unprecedented photocatalytic activity for Fe2O3@BOC1 heterojunction at room temperature could be attributed due to the enhancement in light absorption ability and suppression of electron–hole pair recombination at the heterojunction interface. In addition, reduction in efficacy of the heterojunction with increase in loading of Fe2O3 nanoparticles on BOC surface further confirms the role of interface on the modulation of photocatalytic activity. The role of photogenerated electrons and reactive oxygen species involved during photocatalytic reduction of Cr(VI) and degradation of MB was studied in detail. Moreover, recyclability experiment demonstrates that the developed photocatalyst can be reused without decay in performance. Finally, development of inexpensive prototype reactor is demonstrated towards reduction of Cr(VI) and degradation of MB under continuous flow operation. Thus, good efficacy of the developed reactor for cleaning of toxic pollutants in water makes the heterojunction (Fe2O3@BOC1) a promising photocatalyst for water purification in near future.
关键词： photocatalytic activity,charge separation,Heterojunction,toxic pollutants,visible light
更新于2025-09-23 15:23:52
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Au as a cocatalyst loaded on solid solution Bi0.5Y0.5VO4 for enhancing photocatalytic CO2 reduction activity
摘要： Au as a cocatalyst was deposited on the surface of solid solution Bi0.5Y0.5VO4 by a photodeposition method for photocatalytic reduction of CO2. Au particles loaded on the surface of Bi0.5Y0.5VO4 apparently enhanced the photocatalytic activity of CO2 reduction toward CO evolution. The highest rate of CO evolution was obtained over 1.0 wt% Au/Bi0.5Y0.5VO4, reaching 3.5 times of that of bare Bi0.5Y0.5VO4. The improved photocatalytic performance was assigned to the lower overpotential of Au/Bi0.5Y0.5VO4 for CO evolution than that of bare Bi0.5Y0.5VO4 as well as the formation of Schottky barrier, which promotes the separation of photogenerated electron–hole pairs.
关键词： Semiconductors,Au cocatalyst,Nanocomposites,CO2 reduction,Charge separation
更新于2025-09-23 15:23:52
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Construction of Self-Healing Internal Electric Field for Sustainably Enhanced Photocatalysis
摘要： The construction of internal electric field is generally considered an effective strategy to enhance photocatalytic performance due to its significant role in charge separation. However, static internal electric field is prone to be saturated either by inner or outer shield effect, and thus its effect on the improvement of photocatalysis can easily vanish. Here, the self-healing internal electric field is proposed and successfully endowed to a designed helical structural composite microfiber polyvinylidene fluoride/g-C3N4 (PVDF/g-C3N4) based on the bioinspired simple harmonic vibration. Importantly, the saturation and recovery of internal electric field are characterized by transient photovoltage and photoluminescence. The results indicate that the internal electric field could be saturated within about 10 min and refreshed with the assistance of rebuilt piezoelectric potential. The lifetime of photogenerated carriers is about 10?4 s and the number of effective carriers is greatly increased in the presence of self-healing internal electric field. The results provide direct experimental evidence on the role of self-healing internal electric field in charge transfer behavior. This work represents a new design strategy of photocatalysts, and it may open up new horizons for solving energy shortage and environmental issues.
关键词： charge separation,photocatalysis,microfluidics,bioinspired,self-healing
更新于2025-09-23 15:23:52
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Boosting Visible-light-driven Photooxidation of BiOCl by Promoted Charge Separation via Vacancy Engineering
摘要： The separation of electron-hole pairs has an important influence on the photocatalytic process on semiconductors. In this work, BiOCl nanosheets with oxygen vacancies (BiOCl-OVs) have been prepared by reconstructing small hydrophobic BiOCl nanosheets. The transient photoresponse and the electron spin resonance (ESR) results prove that the separation of the charge carriers can be promoted by the oxygen vacancies via trapping the photoexcited electrons. Due to the improved charge separation and wide absorption of the solar spectrum, more photogenerated charge carriers are produced, as confirmed by the photocurrent response and the ESR measurements of the reactive oxygen species ?O2- and ?OH. Consequently, BiOCl-OVs present enhanced photocatalytic properties towards NO removal. Our study illustrates the importance of the construction of vacancies for improving photocatalytic performance.
关键词： oxygen vacancies,charge separation,BiOCl,NO removal,photocatalytic
更新于2025-09-23 15:23:52