Sunlight‐sensitive plasmonic nanostructured composites as photocatalytic coating with antibacterial properties

Infections caused by microorganisms are a global public health problem that continually demands new antimicrobial strategies. The generation of reactive oxygen species (ROS) by photocatalytic materials is an attractive approach to combat microbes. Along these lines, titanium dioxide (TiO2) constitutes an outstanding light-driven ROS generator. However, the wide bandgap of this semiconductor limits its use to the ultraviolet range of the spectral region. Herein, nanostructured materials composed of TiO2 nanoparticles and plasmonic gold nanorods (AuNRs) are presented for the photoinactivation of bacteria by means of sunlight irradiation, aiming to extend the photocatalytic action of the nanocomposite to the visible and near-infrared ranges. It is shown that, upon simulated sunlight irradiation, the different composites as coating films show photodegradation of rhodamine B, ROS production, photocatalytic inactivation of protein function in bacterial biofilms, and strong antimicrobial activity. This approach involving AuNRs/TiO2 photocatalytic composites may pave the way for the fabrication of visible light-responsive surfaces with antimicrobial activity.Universidade de Vigo/CISU

Balancing near-field enhancement and hot carrier injection: plasmonic photocatalysis in energy-transfer cascade assemblies

Photocatalysisstands as a very promisingalternativeto photovoltaicsin exploitingsolar energyand storingit inchemicalproductsthrougha single-stepprocess.A centralobstacleto its broad implementationis its low conversionefficiency,motivatingresearchin differentfields to bring about a breakthroughin this technology.Using plasmonicmaterialsto photosensitizetraditionalsemiconductorphotocatalystsis a popularstrategywhose full potentialis yet to be fully exploited.In this work, we useCdS quantumdots as a bridge system,reapingenergyfrom Au nanostructuresand deliveringit to TiO2nanoparticlesservingascatalyticcenters.The quantumdots can do this by becomingan intermediatestep in a charge-transfercascadeinitiatedin theplasmonicsystemor by creatingan electron−holepair at an improvedrate due to their interactionwith the enhancednear-fieldcreatedby the plasmonicnanoparticles.Our results show a significantaccelerationin the reactionupon combiningthese elementsinhybrid colloidalphotocatalyststhat promotethe role of the near-fieldenhancementeffect, and we show how to engineercomplexesexploitingthis approach.In doing so, we also explorethe complexinterplaybetweenthe differentmechanismsinvolvedin thephotocatalyticprocess,highlightingthe importanceof the Au nanoparticles’morphologyin their photosensitizingcapabilitiesMinisterio de Universidades | Ref. 33.50.460A.752Ministerio de Ciencia e Innovación | Ref. PDC2021-121787-I00Ministerio de Ciencia e Innovación | Ref. PID2020-113704RB-I00Ministerio de Ciencia e Innovación | Ref. PID2020-118282RA-I00Ministerio de Ciencia e Innovación | Ref. PID2020-120306RB-I00Ministerio de Ciencia e Innovación | Ref. RYC2021-033818-IMinisterio de Ciencia e Innovación | Ref. TED2021-130038A-I00Ministerio de Ciencia e Innovación | Ref. TED2021-132101B-I00Xunta de Galicia | Ref. IN607A 2018/5Generalitat de Catalunya | Ref. 2020SGR00166Centro Singular de Investigación de Galicia | Ref. ED431G 201906National Natural Science Foundation of China | Ref. 22250610200Universitat Rovira i Virgili | Ref. 2021PFR-URV-B2-02United States-Israel Binational Science Foundation | Ref. 2018050Universidade de Vigo/CISU

Deseño de nanohíbridos metal-semicondutor para aplicacións fotocatalíticas

The development of nanohybrids in which a semiconductor as TiO2 is combined with plasmonic nanoparticles produces the formation of photocatalysts with a catalytic activity expanded to a wider region of the electromagnetic spectrum. Such complex materials are capable of absorbing radiation much more efficiently than the original semiconductor. On the other hand, the use of several substrates to form these materials (for example, colloidal silica or polystyrene, thermosensitive polymers or anisotropic oxides) allows controlling the interaction between the plasmonic particles and the semiconductor to optimize the final hybrid depending on the desired application. The main objective of this work will be the development of several hybrid photocatalysts using different substrates in order to optimize the distance, distribution and interaction of the particles to achieve more efficient catalysts depending on the desired application.El desarrollo de nanohíbridos en los que un semiconductor como el TiO2 es combinado con nanopartículas plasmónicas produce la formación de fotocatalizadores con una actividad catalítica que se expande a una región más amplia del espectro electromagnético. Dichos materiales complejos son capaces de absorber radiación de un modo mucho más eficiente que el semiconductor original. Por otro lado, el empleo de varios sustratos para formar estos materiales (por ejemplo, sílice o poliestireno coloidales, polímeros termosensibles u óxidos anisotrópicos) permite controlar la interacción entre las partículas plasmónicas y el semiconductor para optimizar el híbrido final en función de la aplicación deseada. El objetivo fundamental de este trabajo será el desarrollo de varios fotocatalizadores híbridos utilizando diferentes sustratos con el fin de optimizar la distancia, la distribución y la interacción de las partículas para lograr catalizadores más eficientes en función de la aplicación deseada.O desenvolvemento de nanohíbridos nos que un semiconductor como TiO2 é combinado con nanopartículas plasmónicas produce a formación de fotocatalizadores cunha actividade catalítica que se expande a unha rexión máis ampla do espectro electromagnético. Tales materiais complexos son capaces de absorber unha radiación moito máis eficiente que o semicondutor orixinal. Por outra banda, o uso de varios substratos para formar estes materiais (por exemplo, sílice coloidal ou poliestireno, polímeros termosensibles ou óxidos anisótropos) permite controlar a interacción entre as partículas plasmónicas e os semicondutores para optimizar o híbrido final dependendo da aplicación desexada. . O obxectivo principal deste traballo será o desenvolvemento de varios fotocatalizadores híbridos que utilizan diferentes substratos para optimizar a distancia, a distribución e a interacción das partículas para lograr catalizadores máis eficientes dependendo da aplicación desexada