Role of surface water molecules in stabilizing trapped hole centres in titanium dioxide (anatase) as monitored by electron paramagnetic resonance

Panarelli, Enzo Gabriele; Livraghi, Stefano; Maurelli, Sara; Polliotto, Valeria; Chiesa, Mario; Giamello, Elio

doi:10.1016/j.jphotochem.2016.02.015

Cited by 51 publications

(59 citation statements)

References 45 publications

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“…Resonance) it has in fact been possible to distinguish the features of Ocenters in subsurface sites of TiO2 from those of surface O - [51] determining the distance between the hole centers and the protons of coordinating water molecules.…”

Section: Mononuclear Oxygen Speciesmentioning

confidence: 99%

Characterisation and reactivity of oxygen species at the surface of metal oxides

Anpo

Costentin

Giamello

et al. 2021

Journal of Catalysis

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Section: Mononuclear Oxygen Speciesmentioning

confidence: 99%

Characterisation and reactivity of oxygen species at the surface of metal oxides

Anpo

Costentin

Giamello

et al. 2021

Journal of Catalysis

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“… 24 , 25 The calculations suggest that two-coordinated bridging oxygen, O 2 c , is the primary candidate for surface hole trapping. EPR 7 and time-resolved FTIR in the second to minute time scale 21 showed that water adsorbates stabilize surface trapped holes and retard the charge recombination rate. However, the role of interfacing water in charge trapping dynamics is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO₂ Photocatalyst

et al. 2018

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Heterogeneous photocatalysis is vital in solving energy and environmental issues that this society is confronted with. Although photocatalysts are often operated in the presence of water, it has not been yet clarified how the interaction with water itself affects charge dynamics in photocatalysts. Using water-coverage-controlled steady and transient infrared absorption spectroscopy and large-model (∼800 atoms) ab initio calculations, we clarify that water enhances hole trapping at the surface of TiO2 nanospheres but not of well-faceted nanoparticles. This water-assisted effect unique to the nanospheres originates from water adsorption as a ligand at a low-coordinated Ti–OH site or through robust hydrogen bonding directly to the terminal OH at the highly curved nanosphere surface. Thus, the interaction with water at the surface of nanospheres can promote photocatalytic reactions of both oxidation and reduction by elongating photogenerated carrier lifetimes. This morphology-dependent water-assisted effect provides a novel and rational basis for designing and engineering nanophotocatalyst morphology to improve photocatalytic performances.

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“…EPR represents an appropriate tool to determine the course of paramagnetic charge carriers and to investigate the photogenerated charge carrier behaviour, especially the events of photoinduced electrons and holes at the material-reactant interface [9][10][11][12]. In order to improve the C3N4 performance as photocatalyst several approaches have been explored to improve/modify/optimize its structure.…”

Section: Introductionmentioning

confidence: 99%

Photoelectrochemical and EPR features of polymeric C3N4 and O-modified C3N4 employed for selective photocatalytic oxidation of alcohols to aldehydes

et al. 2019

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Four different C3N4 specimens have been prepared, a bulk one (MCN), a thermally etched (MCN-TE), a solid prepared by hydrothermally treating MCN with H2O2 (MCN-H2O2) and a polymeric carbon nitride-hydrogen peroxide adduct (MCN-TE-H2O2). Photoelectrochemical studies revealed that MCN-TE represented the best material in terms of band gap energy and photoconductivity, 2 whereas MCN-H2O2 was defective and evidenced a poor mobility of carriers. EPR studies showed a maximum generation of reactive oxygen species irradiating the MCN-TE sample. The photocatalytic activity of these materials in the selective oxidation of three different alcohols to the corresponding aldehydes, both under UV and natural solar light, showed that the highest conversion was obtained in the presence of the MCN-TE sample, whereas the most selective was MCN-TE-H2O2. Under solar light irradiation the performances of the powders were generally better than those carried under UV light. The characterization of the C3N4-based materials well justified their photocatalytic activity, where the pristine C3N4 materials were more active but less selective than those prepared in the presence of H2O2.

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Role of surface water molecules in stabilizing trapped hole centres in titanium dioxide (anatase) as monitored by electron paramagnetic resonance

Cited by 51 publications

References 45 publications

Characterisation and reactivity of oxygen species at the surface of metal oxides

Characterisation and reactivity of oxygen species at the surface of metal oxides

Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO₂ Photocatalyst

Photoelectrochemical and EPR features of polymeric C3N4 and O-modified C3N4 employed for selective photocatalytic oxidation of alcohols to aldehydes

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Role of surface water molecules in stabilizing trapped hole centres in titanium dioxide (anatase) as monitored by electron paramagnetic resonance

Cited by 51 publications

References 45 publications

Characterisation and reactivity of oxygen species at the surface of metal oxides

Characterisation and reactivity of oxygen species at the surface of metal oxides

Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO2 Photocatalyst

Photoelectrochemical and EPR features of polymeric C3N4 and O-modified C3N4 employed for selective photocatalytic oxidation of alcohols to aldehydes

Contact Info

Product

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About

Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO₂ Photocatalyst