Developing high photocatalytic antibacterial Zn electrodeposited coatings through Schottky junction with Fe3+-doped alkalized g-C_(3)N_(4) photocatalysts

Pure Zn coatings easily lose their protective performance after biofouling because they have no antibacterial effect under visible light.In this study,we fabricate a new antibacterial Zn composite coating using electrodeposition to couple Fe3+-doped alkalized g-C_(3)N_(4)(AKCN-Fe)into an existing Zn coating and show that the AKCN-Fe enhances antibacterial property of the Zn coating under visible light.We attribute this enhancement to the high photocatalytic performance,high loading content,and good dispersion of AKCN-Fe.In addition,the photocatalytic antibacterial mechanism of the composite coating is supported by scavenger experiments and electron paramagnetic resonance(EPR)measurements,suggesting that superoxide(·O_(2)^(-))and hydroxyl radical(·OH)play main and secondary roles,respectively.

Superwetting Ag/α-Fe_(2)O_(3) anchored mesh with enhanced photocatalytic and antibacterial activities for efficient water purification

Superwetting materials have drawn unprecedented attention in the treatment of oily wastewater due to their preferable anti-fouling property and selective oil/water separation.However,it is still a challenge to fabricate multifunctional and environmentally friendly materials,which can be stably applied to purify the actual complicated wastewater.Here,a Ag/Ag/α-Fe_(2)O_(3) heterostructure anchored copper mesh was intentionally synthesized using a facile two-step hydrothermal method.The resultant mesh with superhydrophilicity and underwater superoleophobicity was capable of separating various oil/water mixtures with superior separation efficiency and high permeationflux driven by gravity.Benefiting from the joint effects of the smaller band gap of Ag/α-Fe_(2)O_(3) heterojunction,inherent antibacterial capacity of Ag/α-Fe_(2)O_(3) and Ag nanoparticles,favorable conductive substrate,as well as the hierarchical structure with superwettability,such mesh presented remarkably enhanced degradation capability toward organic dyes under visible light irradiation and antibacterial activity against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)compared with the pure Ag/α-Fe_(2)O_(3) coated mesh.Impressively,the mesh exhibited bifunctional water purification performance,in which organic dyes were eliminated simultaneously from water during oil/water separation in onefiltration process.More importantly,this mesh behaved exceptional chemical resistance,mechanical stability and long-term reusability.Therefore,this material with multifunctional integration may hold promising potential for steady water purification in practice.

Engineering Janus gold nanorod–titania heterostructures with enhanced photocatalytic antibacterial activity against multidrugresistant bacterial infection

Photocatalytic antibacterial approach shows great potential in treating multidrug-resistant bacterial infections.However,the bactericidal efficiency heavily depends on the photocatalytic activity of semiconductor materials,which is limited by the fast recombination of photogenerated electron–hole pairs.Janus nano-heterostructures with spatial control growth of TiO_(2)nanoparticles(NPs)at one end of gold nanorods(Au NRs)are designed via surface ligand regulation for photocatalytic sterilization and infected wound healing.The asymmetric nanostructure of Janus gold nanorod-titanium dioxide nanoparticles(Janus AuNR-TiO_(2) NPs)promotes the directional migration of charge carriers and is more conducive to the spatial separation of electron–hole pairs.Moreover,the injection of hot electrons and enhancement of plasmon near-fields from the surface plasmon resonance(SPR)effect further improve the photocatalytic efficiency of Janus AuNR-TiO_(2) NPs.Under simulated sunlight irradiation,large amounts of reactive oxygen species(ROS)are generated for photocatalytic antibacterial activity.Enhanced bactericidal efficiency up to 99.99%against methicillin-resistant Staphylococcus aureus(MRSA)is achieved in vitro.Furthermore,Janus AuNR-TiO_(2) NPs exhibit superior biocompatibility,structural stability,and also remarkably accelerate MRSA-infected wound healing.Taking the above all into consideration,Janus AuNR-TiO_(2) NPs,as an efficient antibacterial photocatalyst,offers a promising strategy for MRSA infectious therapy.

Au nanorods decorated TiO_(2)nanobelts with enhanced full solar spectrum photocatalytic antibacterial activity and the sterilization file cabinet application

TiO_(2)photocatalysts have been widely studied and applied for removing bacteria,but its antibacterial efficiency is limited to the ultraviolet(UV)range of the solar spectrum.In this work,we use the gold(Au)nanorods to enhance the visible and near-infrared(NIR)light absorption of TiO_(2)NBs,a typical UV light photocatalyst,thus the enhancement of its full solar spectrum(UV,visible and NIR)photocatalytic antibacterial properties is achieved.Preliminary surface plasmon resonance(SPR)enhancement photocatalytic antibacterial mechanism is suggested.On one hand,transverse and longitudinal SPR of Au NRs is beneficial for visible and NIR light utilization.On the other hand,Au NRs combined with TiO_(2)NBs to form the heterostructure,which can improve the photogenerated carrier separation and direct electron transfer increases the hot electron concentration while Au NRs as the electron channel can well restrain charge recombination.finally produces the high yield of radical oxygen species and exhibits a superior antibacterial efficiency.Furthermore,we design a sterilization file cabinet with Au NR/TiO_(2)NB heterostructures as the photocatalytic coating plates.Our study reveals that Au NR/TiO_(2)NB heterostructure is a potential candidate for sterilization of bacteria and archives protection.

ZIF-8 modified by isocyanate as a photocatalytic antibacterial agent

Zeolite imidazole skeleton(ZIF-8)is a promising option for self-cleaning of building exterior walls due to its large specific surface area,high antibacterial activity and low biotoxicity.However,it suffers from low antibacterial efficiency and yield under visible light irradiation.To address the issues,we developed the photocatalytic materials T-ZIF-8-TDI(thermally treated-ZIF-8-toluene 2,4-diisocyanate)by modifying ZIF-8 with thermal oxygen sensitization and chemical bonding.The results show that the yield of T-ZIF-8-TDI photocatalytic antibacterial agent is increased to 11.5 times of that of T-ZIF-8,while maintaining the crystal structure of T-ZIF-8 and thermal stability up to 60℃.Furthermore,T-ZIF-8-TDI exhibits extended optical response range to the nearinfrared region,significantly narrowed band gap,improved photogenerated elec tron-hole separation efficiency,reduced recombination rate,and excellent photocatalytic performance.When the concentration of antibacterial agent is 600 mg·L^(-1),the antibacterial rate of Escherichia coli(E.coli)reaches 99.99%irradiated by visible light for30 min,and when the concentration of antibacterial agent is 200 mg·L^(-1),the antibacterial rate of Staphylococcus aureus(S.aureus)reaches 99.99%irradiated by visible light for 25 min.We also analyzed the reasons in detail from the aspects of bacterial species and antibacterial mechanism,and proposed the antibacterial mechanism of·O_(2)^(-)and h^(+)as the main active species.These findings suggest that T-ZIF-8-TDI photocatalytic antibacterial agent has potential for use in self-cleaning of building exterior walls.

Graphitic carbon nitride loaded with bismuth nanoparticles displays antibacterial photocatalytic activity

Metal-free graphitic carbon nitride nanomaterials have been widely applied in the medical antibacterial field owing to their high anisotropy, excellent stability,satisfactory biocompatibility, and non-toxicity. Herein, Bi/C_(3)N_(4) nanocomposites were successfully constructed by hydrothermal method followed by loading bismuth on the surface of graphite carbon nitride. Bi nanospheres were tightly combined with the layered g-C_(3)N_(4) surface to promote effective separation of photo-induced charges, which results in the Bi/C_(3)N_(4) composite material that exhibited excellent photocatalytic activity under visible light. In addition, the surface plasmon resonance characteristics of semi-metal Bi further enhanced the visible-light absorption of the Bi/C_(3)N_(4). However, excessive Bi may inhibit the light-trapping ability of Bi/C_(3)N_(4).1.0% Bi/C_(3)N_(4) demonstrates excellent bactericidal efficiency as high as 96.4% against Escherichia coli(E. coli), which is attributed to the promotion of the production of reactive oxidative species.The enhanced mechanism of Bi/C_(3)N_(4) synergistically achieving enhanced photocatalytic antibacterial activity under the coupling of multiple advantages was clarified,providing theoretical guidance for its application in the field of water disinfection and antibacterial treatment.

Disruption of Bacterial Cells by Photocatalysis of Montmorillonite Supported Titanium Dioxide

The photo-induced antibacterial capacity of montmorillonite supported titanium dioxide （TiO2/Mmt for short） was evaluated by using Escherichia coli and Staphylococcus aureus as modal organims. The bactericidal activity of TiO2/Mmt was examined by cell viability assay under different illumination modes. Atomic force microscopy （AFM） and total organic carbon/Total nitrogen （TOC/TN） analyses were employed to investigate the mechanism of the photocatalytic bactericidal process qualitatively and quantitatively. The kinetic data show that TiO2/Mmt has excellent antibacterial performance, and about 99% of both bacteria cells are inactivated within 75 rain illumination. The AFM images demonstrate that the bacterial cells are irreversibly decomposed and some cell components are dissolved. Therefore, the content and phase of carbon and nitrogen in the solution are changed after photocatalytic reaction.