NEWS 2019

10 SEPTIEMBRE: Patricia López-Caballero has co-authored her first paper. Congratulations Patricia!!. Press here to see the paper.

10 JULY 2019: A new report about our recent reserach has been published at https://www.lnls.cnpem.br/enhancing-solar-energy-production/

3 MAY 2019: A new report about our recent research has been published at CESGA. Press here to see the report.

8 APRIL 2019: The Book Of Abstracts from the MOLIM WG3 meeting "Ab-Initio Modelling of Molecular Processes Under Confinement" is already available. Press here.

1 APRIL 2019: Today, Patricia López-Caballero, graduate student (in Chemistry) from the Universidad Autónoma de Madrid, has been incorporated into the AbinitSim group. Welcome Patricia!.

26 MARCH 2019: Within the framework of our collaboration with Prof. Andreas W. Hauser's group (Graz University of Technology, Austria), Prof. Arturo M. López-Quintela's group (University of Santiago de Compostela, Spain), and Prof. Félix Requejo's group (CONICET, Argentina), we have just published an article on the deposition of subnanometer-sized Cu5 clusters onto TiO2 surfaces. The work is entitled "Increasing the optical response of TiO2 and extending it into the visible through surface activation with highly stable Cu5 clusters" (de Lara-Castells, Hauser, Ramallo-López, Buceta, Giovanetti, López-Quintela, Requejo; Journal of Materials Chemistry A 7 (2019) 7489).

MOTIVATION

TiO2 is one of the most popular materials for applications such as solar energy conversion and photocatalysis. However, its large band-gap (3-3.2 eV) makes that ultraviolet irradiation is necessary to trigger photo-catalytic reactions. The UV part is less than 8% of the solar radiation so that the reaction rate divided by the photon flux is less than 10%. In our work, we demonstrate via ab-initio modelling that the optical properties of TiO2 are much improved upon deposition of the Cu5 clusters and our fi ndings are further supported by selected experiments. The copper cluster donates electronic charge to TiO2, loosing its magnetic moment and leading to the formation of a small polaron state, which explains X-ray absorption spectroscopy data. More importantly, a monolayer of highly stable copper clusters is formed, which is not only enhancing the overall absorption, but also extending it into the visible region via a direct photo-induced electron transfer and formation of a charge-separated state. The synthesis of these subnanometer-sized metal clusters was achieved using a novel technique that has opened the door to applications such a cancer-therapeutic drugs (www.nanogap.es).

Overall, our study illustrates the suitability of ab-initio modelling in predicting useful properties of subnanometer-sized metal clusters under confinement in the surface of technologically relevant materials. We are currently extending our work to specific photo-induced reactions. So Stay Tuned!.

 

SPANISH VERSION:

26 de Marzo de 2019: Hemos publicado un trabajo que muestra cómo pueden mejorarse las propiedades ópticas de superficies de TiO2 mediante el depósito de agregados subnanométricos de cobre (Cu5). El TiO2 es una de los materiales más populares en aplicaciones fotocatalíticas y de conversión de la energía solar debido a su abundancia, no toxicidad, y estabilidad química. Sin embargo, su gran ancho de banda  (entre 3 y 3.2 eV) hace necesaria la absorción de radiación ultravioleta para desancadenar reacciones fotoinducidas. Esta característica no deseada limita severamente las aplicaciones del TiO2 ya que la parte UV comprende solo el 5-8% de la energía solar. Como consecuencia, la tasa de formación de productos de reacción por fotón incidente es típicamente inferior al 10% en fotocatalizadores basados en TiO2. En nuesto trabajo, hemos demostrado cómo el depósito de agregados de Cu5 de tamaño subnanométrico mejora en órdenes de magnitud la absorción de fotones del material en el ultravioleta, logrando que la absorción se extienda a la región visible. Además, se muestra cómo los agregados Cu5 inducen la formación de pequeños polarones en la superficie de TiO2. El trabajo ilustra la capacidad predictiva de modelizaciones ab-initio multiescala de nuevos materiales nanoestructurados, habiendo sido los resultados teóricos corroborados mediante medidas experimentales.

El artículo es open access y puede ser descargado desde:

https://pubs.rsc.org/en/Content/ArticleLanding/2019/TA/C9TA00994A#!divAbstract