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•Novel direct Z-scheme AgI/Bi4V2O11 photocatalysts were prepared.•A superior photocatalytic activity for the degradation of SMZ refractory pollutants.•A plausible degradation pathway ...for SMZ was proposed.•The fabrication Z-scheme heterostructure play a central role in promoting charge separation and active radical generation.
Z-scheme heterojunction can not only promote the separation of photogenerated carriers, but also retain the strong redox potential of the system, which would greatly improve the photocatalytic performance of catalyst. Herein, a Z-scheme AgI/Bi4V2O11 heterojunction photocatalyst was prepared by a hydrothermal process combined with in situ coprecipitation process. Multiple techniques were employed to investigate the morphology, composition, chemical and electronic properties of the as-prepared samples. The obtained Z-scheme AgI/Bi4V2O11 heterojunction photocatalyst exhibited remarkably enhanced photocatalytic performance towards sulfamethazine (SMZ) degradation under visible light irradiation. Especially, the 20 wt% AgI/Bi4V2O11 composites exhibited the highest photocatalytic activity for sulfamethazine (SMZ) degradation and 91.47% SMZ would be eliminated within 60 min. In comparison with NO3− and SO42−, the presence of Cl− and HCO3− presented more obviously inhibition effects on SMZ degradation. The possible degradation pathways of SMZ were speculated by identifying degradation intermediates. O2−, h+ and OH all involved in the photocatalytic degradation SMZ. The highly enhanced photocatalytic performance might be attributed to form Z-scheme junction between AgI and BVO, which are conducive to the efficient charges separation and maintain high redox potential. This work enriches Bi4V2O11-based Z-scheme heterojunction photocatalytic system and provides a reference for the preparation of effective Z-scheme junction photocatalysts.
A novel Z-scheme system of CeO2–Ag/AgBr heterostructure photocatalyst exhibits excellent ability to eliminate ciprofloxacin under visible light irradiation.
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•Novel Z-scheme ...CeO2–Ag/AgBr photocatalysts were prepared.•Superior photocatalytic activity for the degradation of ciprofloxacin (CIP) refractory pollutants was obtained.•The factors affecting the photocatalytic performance were investigated.•A plausible degradation pathway for CIP was proposed.•A Z-scheme photocatalytic mechanism was proposed.
In this study, CeO2–Ag/AgBr composite photocatalysts with a Z-scheme configuration were fabricated by in situ interspersal of AgBr on CeO2 and subsequent photoreduction process. The CeO2–Ag/AgBr composites exhibited enhanced photocatalytic activity for the photodegradation of ciprofloxacin (CIP) under visible light irradiation. The effects of initial CIP concentration and various inorganic salts were investigated in detail. Three-dimensional excitation–emission matrix fluorescence spectra were used to further monitor the CIP molecule degradation. Plausible degradation pathways for CIP were proposed based on LC-MS instruments. Photoluminescence, electrochemical impedance spectroscopy, and photocurrent tests indicated the rapid transfer and migration of electrons–holes can be achieved in this ternary photocatalytic system. The enhanced photocatalytic performances of CeO2–Ag/AgBr could be credited to the accelerated interfacial charge transfer process and the improved separation of the photogenerated electron–hole pairs. The existence of a small amount of metallic Ag is conducive to the formation of a stable Z-scheme photocatalytic system. This work would pave the route for the design of novel Z-scheme photocatalytic systems for application in solar-to-fuel conversion and photocatalytic water treatment.
SrTiO3/BiOI heterostructure photocatalysts were successfully fabricated through a facile chemical bath method with assistant of the ethylene glycol, which exhibit an efficient charge separation and ...excellent catalytic ability in removing different refractory pollutants.
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•Novel SrTiO3/BiOI heterojunction photocatalysts were fabricated.•A wider application in the degradation of refractory pollutants.•The factors affecting the photocatalytic performance were investigated.•The degradation process of MO and OTTCH was monitor by 3D EEMs.•The in-depth mechanisms insight of charge separation.
Novel SrTiO3/BiOI heterostructure photocatalysts were successfully fabricated through a facile chemical bath method with assistant of the ethylene glycol. The photocatalysts were applied to minimize methyl orange (MO), bisphenol A (BPA), antibiotic oxytetracycline hydrochloride (OTTCH) under visible light irradiation. The SrTiO3/BiOI composites exhibited excellent photocatalytic performance towards the different refractory pollutants. Especially, the sample of STB-22.12 possessed the best photocatalytic performance in all the obtained catalysts. Several reaction parameters affecting degradation such as initial concentration, ion species were investigated systematically. Three-dimensional excitation–emission matrix fluorescence spectroscopy (3D EEMs) was used to further investigate the MO and OTTCH molecule degradation process. The photocatalytic mechanism over composite photocatalyst is systematically investigated by active species trapping experiments, ESR technique and Mott–Schottky measurements. Moreover, the energy band alignments of SrTiO3/BiOI heterostructure were confirmed via combining DRS and XPS analysis, which provided strong support for the proposed mechanism. This work could provide a deeper insight for the heterojunction catalyst.
Electrospun fibrous membranes have the potential to be effective wound dressings for promoting wound healing. However, the fabrication and application of the common electrospun fibrous wound ...dressings are usually complicated and separated. Here, electrospun zein/clove essential oil (CEO) fibrous membranes are fabricated and applied as a potential wound dressing through in situ electrospinning process by a portable electrospinning device. The in situ electrospinning process can directly electrospin zein/CEO membranes onto a wound site to cover the wound well and improve the convenience and comfort in use. The as‐spun zein/CEO membranes show a porous structure and exhibit higher gas permeability at 168.2 ± 43.3 mm s−1, with superhydrophilicity to absorb the wound exudate and good biocompatibility as well as antibacterial effects to protect from infection. Moreover, the mice wound model study suggests that in situ electrospun zein/CEO promotes the wound healing process.
By a portable electrospinning device, zein/clove essential oil fibrous meshes are fabricated in situ and directly deposited onto a wound site as a wound dressing. The as‐spun fabric wound dressing shows porous structure and good antibacterial activity to promote wound healing.
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•New ternary AgBr/CeO2/Ag2CO3 photocatalysts were fabricated.•Superior photocatalytic activity for the degradation of LVF refractory pollutants.•A plausible degradation pathway for ...LVF was proposed.•High mineralization ability for LVF degradation.•An accelerated interfacial charge transfer process was proposed.
Construction of highly efficient ternary photocatalytic systems is strongly attracting the attention of researchers. In this study, a novel ternary Ag2CO3/CeO2/AgBr photocatalyst with a double Z-scheme configuration was fabricated by in situ loading of Ag2CO3 onto CeO2 spindles and subsequently via an acid corrosion process. The ternary Ag2CO3/CeO2/AgBr composites exhibited enhanced photocatalytic activity for the photodegradation of levofloxacin (LVF) under visible light irradiation. Three-dimensional excitation–emission matrix fluorescence spectra revealed that the structure of LVF could be destroyed from the fluorescence point of view; liquid chromatograph–mass spectrometer tests indicated that LVF can be degraded via different pathways; a total organic carbon study showed that LVF could be effectively mineralized. Transient photocurrent response, photoluminescence, and electrochemical impedance spectroscopy indicated that ternary Ag2CO3/CeO2/AgBr composites had fast photoinduced charge separation efficiency. Active-species-trapping experiments and an electron spin resonance technique confirmed that h+, O2−, and OH all participated in a photodegradation process. On the basic of various performance characterization and experimental results, a double Z-scheme photocatalytic mechanism was proposed. It is expected that the ternary Ag2CO3/CeO2/AgBr composites can be used as a promising photocatalyst for energy conversion and environmental remediation. This work could provide a new approach to constructing ternary hybrid photocatalysts and a comprehensive understanding of the degradation pathways for LVF.
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•Novel Ag/AgCl–CeO2 photocatalysts were prepared.•Superior photocatalytic activity for the degradation of NOF refractory pollutants was obtained.•A plausible degradation pathway for ...NOF was proposed.•High mineralization ability toward the NOF molecule degradation was exhibited.•A possible photocatalytic mechanism was proposed.
In this study, CeO2 first was prepared via urea hydrolysis and calcination. Ag/AgCl–CeO2 composite photocatalysts were fabricated by in situ interspersal of AgCl on CeO2 and subsequent photoreduction of AgCl to Ag. The Ag/AgCl–CeO2 composites exhibited enhanced photocatalytic activity for the photodegradation of norfloxacin (NOF) under visible light irradiation. A plausible degradation pathway for NOF was proposed via LC-MS analysis. The Ag/AgCl–CeO2 composites exhibited effective mineralization ability toward the NOF molecule degradation based on three-dimensional excitation–emission matrix fluorescence spectroscopy (3D EEMs) and total organic carbon (TOC) analysis. Transient photocurrent response, PL spectrum, and EIS indicate higher photoinduced charge separation efficiency in Ag/AgCl–CeO2 hybrid composites. Active species trapping experiments and an ESR technique confirmed that h+ and O2− were the main active groups involved in photodegradation of organic pollutants. Through the combination of various performance characterization and experimental results, a possible photocatalytic mechanism was proposed. Furthermore, the catalysts displayed excellent reusability and stability in four consecutive cycles. It is expected that the Ag/AgCl–CeO2 hybrid composites could be used as photocatalysts for energy conversion and environmental remediation. This work can also provide a deeper understanding of the degradation pathway for NOF.
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•Novel plasmonic p-n heterojunction Ag/Ag2O/PbBiO2Br photocatalysts were fabricated.•The synergistic effect between the LSPR effect and the p-n heterojunction promotes charge ...separation and light absorption.•Ag/Ag2O/PbBiO2Br composites present excellent photoactivity for TC degradation under both visible and NIR light irradiation.•Ag/Ag2O/PbBiO2Br composites bring new insights into the construction of novel plasmonic p-n heterojunction photocatalysts.
Among several factors that influence the effectiveness of a semiconductor mediated photocatalysis, efficient charge separation and broadened light absorption are regarded as two of the most important parameters. Herein, a series of plasmonic p-n heterojunction Ag/Ag2O/PbBiO2Br photocatalysts with wide spectrum responses were successfully fabricated through a facile precipitation-calcination method. The obtained samples display exceptional photocatalytic performance for the degradation of tetracycline (TC), and the results reveal that the 10 wt% Ag/Ag2O/PbBiO2Br exhibits the optimal activity, which can efficiently decompose 84.4% of TC after 90 min of visible light irradiation. While under NIR light irradiation, the TC removal ratio can still reach 50.9% with 240 min. Besides, no significant deterioration in the degradation performance is observed even after four cycling runs. The photoactivity enhancement of Ag/Ag2O/PbBiO2Br can be credited to the synergistic effect between the local surface plasmon resonance (LSPR) effect of metallic Ag and the p-n heterojunction of Ag2O/PbBiO2Br, which not only greatly broadens the light utilization, but also remarkably accelerates the charge separation. The radical trapping experiments and the ESR measurements ascertains that O2−, h+ and OH play a critical role in the degradation of TC under visible light irradiation, while O2− and h+ become the major reactive species in NIR light-driven reaction. According to the experimental results, the plausible reaction mechanisms for TC degradation over Ag/Ag2O/PbBiO2Br composite are proposed under both visible and NIR light irradiation. This work provides some guidance for rational construction of novel plasmonic p-n heterojunction photocatalysts to meet ever-increasing environmental requirements.
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•Novel highly efficient visible-light-driven photocatalytic system Co3O4/CeO2/PMS is prepared.•87.8% of CIP could be removed within 50 min visible illumination.•The addition of PMS ...produced the synergetic effect in Co3O4/CeO2 photocatalytic system.•A plausible degradation pathway for CIP was proposed.•The in-depth mechanisms insight of charge separation.
The development of simple and effective approaches for the synthesis of bimetallic oxide heterojunction photocatalyst which are used to activate peroxymonosulfate (PMS) under visible-light-driven is highly feasible but remains a great challenge. In this work, the Co3O4/CeO2 composite was prepared by a facile chemical reaction, followed by annealing in a muffle furnace and then applied to activate PMS for ciprofloxacin (CIP) degradation. Various characterizations confirmed the formation of p-n heterojunction between Co3O4 and CeO2. Meanwhile, the 5 wt% Co3O4/CeO2/PMS composite showed highest degradation rate of CIP (87.8%) under visible light irradiation. The obtained Co3O4/CeO2/PMS system still exhibited a good catalytic performance in presence of different anion. Besides, the active radical h+, OH, O2−, and SO4− are involved in CIP degradation. The excellent degradation performance can be interpreted as the synergistic effect between Co3O4/CeO2 heterojunction photocatalyst and PMS activation. Moreover, the energy band structure and valence band deviation of Co3O4/CeO2 p-n heterogeneous junction were confirmed. This work would give a reference for combining the photocatalyst and activation of PMS under visible light for further removal of pollutants.
Smart hydrogels, or stimuli-responsive hydrogels, are three-dimensional networks composed of crosslinked hydrophilic polymer chains that are able to dramatically change their volume and other ...properties in response to environmental stimuli such as temperature, pH and certain chemicals. Rapid and significant response to environmental stimuli and high elasticity are critical for the versatility of such smart hydrogels. Here we report the synthesis of smart hydrogels which are rapidly responsive, highly swellable and stretchable, by constructing a nano-structured architecture with activated nanogels as nano-crosslinkers. The nano-structured smart hydrogels show very significant and rapid stimuli-responsive characteristics, as well as highly elastic properties to sustain high compressions, resist slicing and withstand high level of deformation, such as bending, twisting and extensive stretching. Because of the concurrent rapid and significant stimuli-response and high elasticity, these nano-structured smart hydrogels may expand the scope of hydrogel applications, and provide enhanced performance in their applications.
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•The historical development of AgI based photocatalytic systems is summarized.•The recent crucial applications and progress of AgI based photocatalytic systems are presented.•The ...roles of AgI in difference photocatalytic system are deeply discussed.•Exciting perspectives on AgI based photocatalytic systems are pointed.
Over the past years, photocatalytic technology has exhibited a great potential in treating wastewater, splitting water to hydrogen and reducing CO2 to fuel. Among, more and more researchers attempt to design AgI based heterojunction photocatalytic systems for developing novel photocatalysts with excellent performance. However, a review about AgI based photocatalytic systems is still absent. Herein, two the charge carrier transfer processes in Type II and Z-scheme heterojunction photocatalytic system were firstly presented systemically. Then the recent developments of AgI based different heterojunction photocatalytic systems were summarized. The photocatalysts commonly modified by AgI are classified, and the role of AgI in different heterojunction photocatalytic systems is analyzed in detail. Additionally, the application of AgI based composites in environmental restoration and energy conversion field are presented including degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction and disinfection. Meanwhile, the typical mechanism of these photocatalytic reactions based on AgI composites is also described in detail. Finally, unresolved challenges and potential applications of AgI based composites are presented for guiding the direction for future development.
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