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The development of multifunctional antibacterial materials based on semiconductor materials has become the focus of treatment in the field of antibiotic-resistant bacteria. Here, for the first time, the superb photocatalytic/photothermal antibacterial activity of BP/MoS2 and BP/WS2 nanocomposites against both E. coli and S. aureus under near-infrared (NIR) or light-emitting diode (LED) illumination was demonstrated. Characterization studies using advanced instrumental techniques confirmed the successful formation of BP/WS2 and BP/MoS2 S-scheme heterojunctions with distinct structural, morphological, and compositional features. Moreover, it was verified that the enhanced photo-antibacterial activity of both heterojunctions compared to their pristine analogs was demonstrated to be due to the synergistic interactions at the atomic level elucidated by Mo/W–S–P via a sulfur atom bridge in X-ray photoelectron spectroscopy analysis, which improves the charge flow and enhances the photocatalytic performance. Optical density measurements were performed to obtain bacterial growth over 4 h, where BP/WS2 (≅88%) and BP/MoS2 (≅83%) showed higher NIR light-driven antibacterial activity compared to the pristine analogs (BP nanosheets, WS2 or MoS2 nanostructures), which is attributed to the S-scheme heterojunctions formed between BP and MS2 that enhance the production of ROS by promoting the use of light-induced carriers. The photo-antibacterial activities of BP/WS2 and BP/MoS2 heterojunctions reached 93% and 98%, respectively. The bacterial mechanical rupture effect of BP/WS2 and BP/MoS2 heterojunctions was monitored using SEM and E. coli was found to be more resistant to damage than S. aureus. The ability of BP/WS2 and BP/MoS2 to generate reactive oxygen species (ROS) was better than that of pristine BP nanosheets, as demonstrated by a glutathione (GSH) oxidation assay. The photothermal activities of the nanocomposites were investigated to explain the photoinduced antibacterial mechanism. In addition, the photo-antibiofilm activities of BP/WS2 and BP/MoS2 heterojunctions were also investigated and the biofilm structure of S. aureus was almost completely eradicated under LED light irradiation. [ABSTRACT FROM AUTHOR]

Piezocatalysis shows promise to diversify hydrogen production methods and solve problems in photocatalysis such as high charge recombination and low solar light absorption by waste mechanical energy. Scheelite type BaWO4 and BaMoO4 have been used in piezocatalytic hydrogen production due to their non-centrosymmetric crystal structure and piezoelectric and electrochemical properties for the first time. Piezocatalytic hydrogen production of BaMoO4 and BaWO4 was observed to be 198 and 313 μmol g−1 h−1, respectively, under ultrasonic sound. In order to increase the piezocatalytic hydrogen production activities, in situ Ag piezodeposition was performed on BaMoO4 and BaWO4 catalyst surfaces, and the hydrogen production was found to be 365 and 469 μmol g−1 h−1, respectively. Schottky junctions between BaWO4 and Ag (or BaMoO4 and Ag) enhanced the separation and migration of piezoelectric polarization charges formed on the non-centrosymmetric unit cells. Moreover, photopiezocatalytic hydrogen production of BaMoO4 and BaWO4 was investigated by application of both visible light irradiation and ultrasonic sound, and then it reached 789 and 1103 μmol g−1 h−1, respectively. The bending of valence and conduction bands of BaWO4 and BaMoO4 occurs under mechanical stress, can lead to a reduced band gap energy. BaWO4 and BaMoO4 generate photoexcited charges under visible light illumination, providing support for the piezocatalytic hydrogen evolution reaction. The most enhanced hydrogen production rates were obtained under photopiezocatalytic conditions by using BaMoO4/Ag and BaWO4/Ag as 1560 and 2146 μmol g−1 h−1, respectively. Piezocatalytic hydrogen production of piezocatalysts was examined for 6 hours under mechanical stress, and it was observed that piezocatalytic hydrogen production continued to increase significantly during the 6-hour reaction. In addition, reusability tests of piezocatalysts for hydrogen production were carried out and it was determined that all catalysts sustained meaningful stability throughout 6 cycles. These piezocatalytic hydrogen production activities among catalysts are confirmed by piezoresponse force microscopy, electrochemical impedance spectroscopy and chronoamperometry measurements. This study will pave the way for light induced piezocatalytic applications by different heterojunctions, nanocomposite catalysts etc. [ABSTRACT FROM AUTHOR]

Viologens are well-suited for serving as electron-transfer mediators in redox systems due to their low reduction potential and ability to form stable radical cations. Because of this feature, viologens can play a key role in modifying semiconductors toward enhanced photocatalytic performance. Herein, a series of hybrid photocatalysts composed of TiO2 nanoparticles and star-shaped viologen derivatives with different alkyl chains [TPCBP-X_TiO2; X: ethyl (E), butyl (B), hexyl (H) and octyl (O)] were prepared for the photocatalytic hydrogen evolution from water under visible-light irradiation. The TPCBP-X molecules not only provide photosensitization of TiO2 nanoparticles in the visible-light region but also act as an efficient electron-transfer mediator for the transfer of photoinduced electrons to TiO2 and Pt. Among these photocatalysts, TPCBP-E_TiO2 exhibited a 1.013 mmol g–1 h–1 H2 evolution rate with an apparent quantum yield (AQY) of 20.15% (470 nm), which dramatically improved hydrogen evolution activity among the other structures [TPCBP-X_TiO2 (X; B, H, O)] due to the more porous and uniform surface, resulting in its low barrier effect for electron transfer. In addition, in the presence of a Pt cocatalyst, TPCBP-E_TiO2 yielded a H2 evolution rate of 17.7 mmol g–1, which is about 2.2 times higher than that of pure TPCBP-E_TiO2 (8.1 mmol g–1) after 8 h of visible-light illumination. [ABSTRACT FROM AUTHOR]

Foodborne infections are one of the most important problems in the protection of human health. Bacillus cereus and Salmonella enteritidis as the most common foodborne pathogens are the main cause of food poisoning. Due to the inadequacy of traditional antibiotics, biofilm formation and increase in resistant species, the control of the pathogen growth is a quite challenging issue. Recently, Black Phosphorus (BP) nanosheets as a rising star 2D semiconductor, has attracted great attention due to their specific surface interface interactions. Photo‐activated BP‐based nanocomposites could trigger the release of inorganic nanoparticles, creating superior antibacterial functions. In this work, NIR light‐induced antibacterial activities of pristine BP nanosheets, BP/Ag and BP/Au nanocomposites were tested on Bacillus cereus and Salmonella enteritidis and both of BP/Au or BP/Ag exhibited superior growth inhibition efficiencies compared to pristine BP nanosheets due to the active sites for physical contact with bacterial membranes as well as production of ROS. SEM analysis proved that BP‐based nanocomposites create physical membrane damages. Antibiofilm activities of the nanocomposites were also examined, which is higher than BP nanosheets alone. Accordingly, due to the sharp edges, NIR‐triggered photothermal effect and Schottky interaction of nanocomposites the biofilm structure was mechanically damaged. This work provides an idea to control the growth of bacteria by BP‐based nanocomposites, which have the potential to be used in large‐scale approaches as an alternative to antibiotics. [ABSTRACT FROM AUTHOR]

A series of SubPcs comprising a carboxylic acid anchoring group at the peripheral (SubPcs 1, 2) or axial position (SubPc 3) were synthesized and used as sensitizers for photocatalytic H2 production, for the first time. SubPc 3/TiO2 shows the best photocatalytic activity with a hydrogen evolution rate of 1396 μmol h−1, which is much higher than that of SubPcs 1 and 2 (771 and 658 μmol g−1, respectively). This work clearly shows that considering their optical and redox properties, SubPcs are promising candidates for light-driven water splitting systems. [ABSTRACT FROM AUTHOR]

NixSy (NiS and Ni1718y) nanoparticles and their nanocomposite with carbon nanotubes (NixSy/CNT) were synthesized by a modified hydrothermal method and characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray microanalysis. The synthesized materials were used as hydrogen evolution catalysts at the water/1,2-dichloroethane interface by using decamethylferrocene as a lipophilic electron donor. The hydrogen evolution reaction in biphasic systems was investigated by two-phase reactions and by cyclic voltammetry with a four-electrode system. A kinetic study of the hydrogen production was also performed. The rates of the reactions catalyzed by the NixSy nanoparticles and the NixSy/CNT nanocomposite were found to be about 690-fold and 2000-fold higher, respectively, than the rate for the reaction performed in the absence of a catalyst. [ABSTRACT FROM AUTHOR]

The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2NiSnS4>Cu2FeSnS4>Cu2CoSnS4>Cu2ZnSnS4>Cu2MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g−1 h−1, respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2NiSnS4, Cu2FeSnS4, and Cu2CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light. [ABSTRACT FROM AUTHOR]

A series of SubPcs comprising a carboxylic acid anchoring group at the peripheral (SubPcs 1, 2) or axial position (SubPc 3) were synthesized and used as sensitizers for photocatalytic H2 production, for the first time. SubPc 3/TiO2 shows the best photocatalytic activity with a hydrogen evolution rate of 1396 μmol h-1, which is much higher than that of SubPcs 1 and 2 (771 and 658 μmol g-1, respectively). This work clearly shows that considering their optical and redox properties, SubPcs are promising candidates for light-driven water splitting systems.

The present study reports, for the first time, both a facile synthesis for ternary Cu 2 WS 4 nanocubes, which were synthesized by a simple and low-cost hot-injection method, and the hydrogen evolution reaction at a biomembrane-like polarized water/1,2-dichloroethane interface catalyzed by Cu 2 WS 4 nanocubes. The rate of hydrogen evolution reaction is increased by about 1000 times by using Cu 2 WS 4 nanocubes when compared to an uncatalyzed reaction.

The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1) h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4, Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photocatalytic generation of hydrogen by using oleic acid-capped CdS, CdSe, and CdS(0.75)Se(0.25) alloy nanocrystals (quantum dots) has been investigated under visible-light irradiation by employing Na(2)S and Na(2)SO(3) as hole scavengers. Highly photostable CdS(0.75)Se(0.25) alloy nanocrystals gave the highest hydrogen evolution rate (1466 μmol h(-1) g(-1)), which was about three times higher than that of CdS and seven times higher than that of CdSe., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)