查找使用阿拉丁产品的科研文献

Aqueous synthesis of composition-tuned defects in CuInSe2 nanocrystals for enhanced visible-light photocatalytic H2 evolution

Senlin Qu,Xin Yuan,Yu Li,Xingyang Li,Xiujuan Zhou,Xiaogang Xue,Kexiang Zhang,Juan Xu,Changlai Yuan

The composition and defect tolerance of CuInSe2 (CISe) quantum dots (QDs) provide a scaffold to design defects via tailoring the elemental ratio or distributions for boosting photocatalytic H2 evolution (PHE). Herein, a ligand-assisted two-step aqueous method was developed to prepare defect CISe quantum dots for the first time. UV-vis, XPS, HRTEM, and HADDF investigations confirmed the typical double-absorption edges of copper vacancy defects and indium substituted at copper site defects in the structure constructed through initial synthesis tuned by Cu/In ratio and the ensued coarsening. The steady-transient PL suggested that the D–A recombination with prolonged PL lifetime dominated the emission of composition-optimized CuInSe2 with the Cu/In ratio of 1/4 (CISe-1/4). Further transient photocurrent and electrochemical impedance spectroscopy investigations demonstrated that surface defects in the structure favor the carriers' separation/transportation. The CISe-1/4 exhibited a superior PHE rate of 722 μmol g−1 h−1, about 23 times higher than that of the initially synthesized CISe-1/4 nucleus (31 μmol g−1 h−1), with a maximum apparent quantum efficiency (AQE) of 1.3%. The analysis of energy levels and the coulombic interaction energy of electron–hole (Je/h) based on Raman, extending UV-vis spectra investigations suggested that surface defects resulted in decreased Je/h of CISe-1/4, favoring the enhanced PHE of this structure. This work is expected to provide a reference for designing effective non-noble metal I–III–VI photocatalysts.

Enhanced visible-light-driven photocatalytic activity of Bi2WO6-BiSI Z-scheme heterojunction photocatalysts for tetracycline degradation

Rui Zhang,Kunlin Zeng,Tongqing Zhang

Dynamic emulsion droplets enabled by interfacial assembly of azobenzene-functionalized nanoparticles under light and magnetic field

Guangbin Ji,Fei Yang,Yanzhao Yang,Jingjing Wei,Zhijie Yang

Hypothesis The ability to control the assembly of micro/nanosized particles at liquid-liquid interface with external inputs promises new opportunities in nanofabrication and biomedicines. This work aims to demonstrate a way to control of dynamic assembly of nanoparticles at liquid-liquid interface by light and magnetic field, which consequently enables the formation of dynamic emulsion droplets. Experiments Magnetic Fe 3 O 4 nanoparticles functionalized with azobenzene moieties (Fe 3 O 4 @AZO) were synthesized and were dispersed in toluene/(N, N -dimethylformamide, DMF) binary solvent. After irradiation with UV or visible light , the assembly behavior of these Fe 3 O 4 nanoparticles were evaluated by electron microscopy and fluorescent microscopy. Findings Under UV light , Fe 3 O 4 @AZO nanoparticles were self-assembled due to the increase of dipolar interaction from the photoisomerization of azobenzene and polar molecules , DMF, were harvested from a binary solvent of DMF/toluene. While under visible light, a relief of dipolar interactions between Fe 3 O 4 @AZO nanoparticles can induce the secondary assembly of these Fe 3 O 4 @AZO nanoparticles at DMF-toluene interface, resulting in DMF droplets covered by a layer of nanoparticle superlattices . More importantly, coupled with a magnetic field, these emulsion droplets can be shaped into one dimensional ones during the interfacial assembly process, thereby giving rise to dynamic emulsions controlled by light and magnetic field.

Silver-decorated, light-activatable polymeric antimicrobials for combined chemo-photodynamic therapy of drug-resistant bacterial infection

Xiaoxue Hou,Lijun Yang,Jinjian Liu,Yumin Zhang,Liping Chu,Chunyan Ren,Fan Huang,Jianfeng Liu

Drug-resistant bacterial infections have stolen the spotlight in recent years as stubborn diseases intimidating public health, thus urgently requiring the development of innovative treatment strategies with high antibacterial efficiency and low bacterial resistance. Here, a polymeric antimicrobial with synergistic chemo-photodynamic therapy function is fabricated to combat drug-resistant bacterial infections. In this strategy, polymeric micelles based on amphiphilic poly(aspartic acid)-block-poly(ε-caprolactone) (PAsp-b-PCL) are used as nanocarriers to encapsulate a photosensitizer protoporphyrin IX (PpIX) in the micellar core, which then undergo silver nanoparticle decoration on the micellar shell through an in situ reduction method. Compared with mono-therapy, the combination of silver nanoparticle decoration and light-activatable PpIX enables the resulting polymeric antimicrobial to exert chemo-photodynamic activity to kill drug-resistant bacteria more potently in vitro. Furthermore, the prepared polymeric antimicrobials with synergistic antibacterial activity show robust eradication efficacy against subcutaneous infections induced by drug-resistant Staphylococcus aureus in a murine model. Therefore, our study provides a simple and potent strategy to realize combination therapy for eradicating drug-resistant bacterial infections.

2-Methylimidazole-modulated UiO-66 as an effective photocatalyst to degrade Rhodamine B under visible light

Li Zhaohua,Hu Rui,Ye Shuai,Song Jun,Liu Liwei,Qu Junle

Abstract We report herein a versatile new approach for improving the photodegradation performance of UiO-66 by introducing 2-methylimidazole through a straightforward in situ one-pot solvothermal method. The resultant complex UiO-66-M-0.7 has demonstrated a reaction rate constant of 0.0183 min −1 in the photodegradation of rhodamine B under visible light, which is 69.4% higher than that with unmodulated UiO-66. Further investigation has confirmed that the improved activity can be attributed to enhanced adsorption of the dye by the photocatalyst during the adsorption–desorption equilibrium. The main active species involved in the photodegradation process have been identified as h + and O 2 − ·. In addition, the complex has shown ideal stability in recycling tests and excellent activity in the degradation of methylene blue. This study provides a novel perspective for the future design of various photocatalysts with superior performance. Graphic abstract 2-Methylimidazole-modulated UiO-66 exhibits increased catalytic performance in the photodegradation of rhodamine B (RhB) under visible light because of enhanced adsorption of RhB on the catalyst during the adsorption-desorption equilibrium.

Effects of UVC light-emitting diodes on microbial safety and quality attributes of raw tuna fillets

Liumin Fan,Xiao Liu,Xiuping Dong,Shanshan Dong,Qisen Xiang,Yanhong Bai

Ultraviolet light-emitting diodes (UV-LEDs) have become widespread for decontaminating the surfaces of food products and their packaging as a safer alternative to traditional mercury-vapor based UV lamps. This study aimed to investigate the effect of UVC- LEDs (275 nm) on the inactivation of foodborne pathogens and quality attributes of raw tuna fillets. Raw tuna fillets inoculated with cocktails of Salmonella Typhimurium, Listeria monocytogenes , and Escherichia coli O157:H7 were exposed to UVC-LEDs at 500-4000 mJ/cm 2 . UVC-LED treatments of single-layer tuna fillets at a dose of 4000 mJ/cm 2 resulted in 1.31-, 1.86-, and 1.77- log reduction of S . Typhimurium, L . monocytogenes , and E . coli O157:H7, respectively. The pH value, water-holding capacity, metmyoglobin, texture, and color characteristics of tuna fillets were not significantly ( p  > 0.05) changed following the UVC-LED treatment at radiation doses up to 4000 mJ/cm 2 . Nonetheless, the UVC-LED irradiation led to increased levels of lipid oxidation in tuna fillets. Overall, the present study demonstrates that UVC-LEDs are a promising technology to reduce microbial flora and maintain the physicochemical properties of fish products.

La-Doped ZnO/g-C3N4 Heterojunction for Efficient Degradation of Organic Contamination Under Visible Light Irradiation

Xu Gengsheng,You Fangfang,Li Xu

Considering the accelerated charge/mass transfer and the formation of active defects at the heterointerface, La-ZnO/g-C 3 N 4 heterogeneous photocatalysts were facilely prepared via a two-step route consisting of hydrothermal and calcination processes in this work. The combination of La 3+ doping in ZnO and the contact between La-ZnO and g-C 3 N 4 endowed the heterogeneous composite with a much enhanced photocatalytic activity towards methyl blue (MB) dye decolorization under the visible light irradiation. It was found that La-ZnO/g-C 3 N 4 -4.6 showed an optimal degradation rate of MB (8.72 × 10 − 2 min − 1 ), which is 14 times higher than that of pure g-C 3 N 4 (6.23 × 10 − 3 min − 1 ) under the same experimental conditions. The improved photocatalytic MB decolorization is attributed to the increased interfacial electron-hole separation efficiency through constructing La-ZnO/g-C 3 N 4 heterogeneous interfaces. The present study manifests the advantage of heterogeneous interfaces as the charge carrier separation pathway towards boosting photocatalytic activity.

Enhanced photodynamic inactivation for Gram-negative bacteria by branched polyethylenimine-containing nanoparticles under visible light irradiation

Qian Wang,Dandan Zhang,Jin Feng,Tingli Sun,Cailing Li,Xiaobao Xie,Qingshan Shi

Antibiotic pollution has been a serious global public health concern in recent years, photodynamic inactivation is one of the most promising and innovative methods for antibacterial applications that avoids antibiotic abuse and minimizes risks of antibiotic resistance . However, limited by the weak interaction between the photosensitizers and Gram-negative bacteria, the effect of photodynamic inactivation cannot be fully exerted. Herein, photosensitizer chlorin e6-loaded polyethyleneimine-based micelle was constructed. The synergy of electrostatic and hydrophobic interactions between the nanoparticles and the bacterial surface promoted the anchoring of nanoparticles onto the bacteria, resulting in enhanced photoinactivation activities on Gram-negative bacteria. As expected, an eminent antibacterial effect was also observed on the Gram-positive bacteria Staphylococcus aureus . The cellular uptake results showed that photosensitizer was firmly anchored to the bacterial cell surface of Escherichia coli or Staphylococcus aureus by the introduction of branched polyethylenimine-containing nanoparticles. The light-triggered generation of reactive oxygen species , mainly singlet oxygen, from the membrane-bound nanoparticles caused irreversible damage to the bacterial outer membrane, achieving enhanced bactericidal efficiency than free photosensitizer. The study would provide an efficient and promising antimicrobial alternative to prevent overuse of antibiotics and have enormous potential for human healthcare and the environment remediation.

Facile Synthesis of Anatase–Rutile Diphase N-doped TiO2 Nanoparticles with Excellent Visible Light Photocatalytic Activity

Jun Liu,Xuli Li,Haobo Hou,Min Zhou

To further boost the charge separation and photocatalytic activity of TiO2under visible light, the anatase–rutile mixed-phase nitrogen-doped (N-doped) TiO2nanoparticles were successfully synthesized through a facile one-step calcining procedure using TiN as raw materials. The crystal phases, morphologies, chemical compositions, textural structures, and optical properties of as-obtained N-doped TiO2were characterized by the corresponding analytical techniques. The photocatalytic activities of as-fabricated samples were evaluated by degrading 4-chlorophenol (4-CP) and methylene blue (MB) aqueous solution under visible light irradiation. The results revealed that the ratio of rutile to anatase increased with the improvement of sintering temperature, and the sample prepared at 500 °C had the best photocatalytic activity. This might be because it possessed the most appropriate rutile/anatase proportion as well as the nitrogen doping. The transient photocurrent responses, photoluminescence spectra (PL) measurements, and active species trapping experiments were implemented to disclose the photocatalytic mechanism. This work will provide a further insight into the synthesis of highly efficient N-doped TiO2photocatalysts for organic contaminant removal.Keywords:N-doped TiO2;charge separation;photocatalytic activity

Photodeposition synthesis of CdS QDs-decorated TiO2 for efficient photocatalytic degradation of metronidazole under visible light

Wang Peng,Xu Shiyu,Wang Jiayu,Liu Xuezheng

Photocatalysis technology has received much attention on the treatment of antibiotics residues. In this paper, CdS quantum dots (QDs)-decorated TiO 2 (CDS-T for short) have been prepared successfully through a photodeposition method and utilized as photocatalysts for degradation of metronidazole (MTZ). Under visible light irradiation for 60 min, the degradation ratio of MTZ over CDS-T-3 that was prepared by 3 h of photodeposition reached up to 90.9%, which was 1.5 times than that reached over commercial CdS. The decoration of CdS QDs onto TiO 2 can enlarge light absorption range to visible region. Furthermore, greatly improved separation efficiency of photogenerated carriers is realized through forming heterojunction. Activity control experiments demonstrate that O 2 · − serve as the main active species, while ·OH and holes (h + ) play secondary roles on the MTZ degradation. Moreover, electron spin resonance (ESR) technique, terephthalic acid photoluminescence (TA-PL) technique and N,N-diethyl-p-phenylenediamine (DPD) method confirm that larger amounts of active species are generated from CDS-T-3 than that from commercial CdS under visible light. This study can not only offer an easy method to prepare CdS quantum dots-decorated TiO 2 but also enlarge its application in solving the problem of metronidazole contamination.

Visible light absorption by perylene diimide for synergistic persulfate activation towards efficient photodegradation of bisphenol A

Qiuyi Ji,Xinying Cheng,Yijie Wu,Weiming Xiang,Huan He,Zhe Xu,Chenmin Xu,Chengdu Qi,Shiyin Li,Limin Zhang,Shaogui Yang

A novel PDI/PS/Vis system was constructed and the photocatalytic activity of PDI with various degrees of self-assembly was explored. Perylene diimide (PDI) as photocatalysts possesses excellent charge separation efficiency and the electron injection from the PDI to persulfate (PS) can produce active species more efficiently. With the PDI/PS/Vis system, 5 mg/L bisphenol A (BPA, 50 mL) could be completely removed in 15 min with 0.5 g/L photocatalyst and 1.5 mM PS under visible light (λ>420 nm). Nearly 71.1 % of BPA was mineralized after 1 h degradation. Radical quenching tests and electron paramagnetic resonance (EPR) spectra revealed that h + , ·O 2 − , ·OH and SO 4 ·- all contributed to organics elimination with radical process. Based on the results of theoretical calculations and toxicity assessment, BPA will eventually be converted into non-toxic ring-opening products. Therefore, the highly efficient PDI/PS/Vis system has great potential for application in water environment remediation.

All-Inorganic Perovskite Nanosheet Fabrication under Synergistic Effect for Integrated Optoelectronics with Strong Light–Matter Interactions

Yeming He,Yang Ma,Xuhong Li,Yongzhe Zhang

All-inorganic perovskites have emerged in the field of optoelectronic devices for their excellent light absorption and energy conversion efficiencies, as well as their superior stability compared to organic–inorganic perovskites. The two-dimensional (2D) all-inorganic perovskites have a higher exciton binding energy and carrier recombination efficiency than their bulk counterparts due to the quantum confinement effect, which indicts high strong light–matter interactions and is suitable for special integrated optoelectronics such as a micro laser or quick-response photodetector. However, it is difficult to fabricate a 2D large-sized sample with high crystal quality due to the nonlayered structure, which limits its further research and practical application. In this work, based on an atmospheric pressure chemical vapor deposition strategy combining a space-confined method and van der Waals epitaxy, the synergistic effect of these two techniques results in large-sized ultrathin all-inorganic CsPbI3 perovskite nanosheets for which the lateral dimension can exceed 50 μm while the smallest thickness can reach 3 nm. The high crystal quality of the square-like samples has been confirmed by a microstructure characterization, while the corresponding performances like long carrier life (360 ns), high resistivity, and good stability were also verified, implying great promise for their applications in high-performance integrated optoelectronics. This method may pave the way for a uniform fabrication of other 2D nonlayered materials as well.