Heterogeneous photocatalysis. Dynamics of charge transfer in lithium-doped anatase-based catalyst powders with enhanced water photocleavage under ultraviolet irradiation

Kiwi, J.; Morrison, Colin L.

doi:10.1021/j150669a018

Cited by 67 publications

(31 citation statements)

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“…The O 2 in the RF-plasma cavity reacts with the PE inducing surface groups like C O, C O, O C O, C O O − , in addition to other polar/hydrophilic groups, breaking intermolecular PE H H bonds. These negative functionalities bind TiO 2 by electrostatics and chelation/complexation [24][25][26][27][28]38].…”

Section: Methodsmentioning

confidence: 99%

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Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

Rtimi

Giannakis

Bensimon

et al. 2016

Applied Catalysis B: Environmental

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a b s t r a c tInsight is provided in this study for the effect of the TiO 2 film densification/compactness on polyethylene (PE-TiO 2 ) by sputtering TiO 2 at two very different energy levels. Uniform, adhesive low energy films were prepared by direct current magnetron sputtering (DCMS) and compared with films sputtered at high energy levels by high power impulse magnetron sputtering (HIPIMS). Nano-particulate TiO 2 films sputtered by HPIMS presented sizes of ∼10.2 nm compared to films sputtered by DCMS with TiO 2 sizes of ∼16.5 nm as determined by X-ray diffraction (XRD). The E. coli inactivation kinetics was three times faster for the samples sputtered by HIPIMS compared to their DCMS counterparts. This is an unexpected finding since the DCMS presenting larger TiO 2 sized nanoparticles released a higher amount of Ti-ions compared to the HIPIMS samples as monitored by inductively coupled plasma mass-spectrometry (ICP-MS). The Ti-ions released do not seem to react through an oligodynamic effect but diffuse through the less compact TiO 2 sputtered by DCMS. The faster bacterial inactivation kinetics observed by the HIPIMS sputtered samples can be understood in terms of the complete of Ti 4+ /Ti 3+ redox conversion during bacterial inactivation detected by X-ray photo-electron spectroscopy (XPS) compared to the smaller Ti 4+ /Ti 3+ effect observed in the DCMS-samples. A higher optical density was detected for the HIPIMS sputtered samples by diffuse reflectance spectroscopy (DRS). Evidence is presented for the shift in surface potential and local pH during bacterial inactivation under aerobic and anaerobic conditions. A reaction mechanism is suggested based on the findings described in this study. The sputtered films present the potential to hinder biofilm formation on flexible thin polymers/textiles widely used in hospitals and health facilities.

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Section: Methodsmentioning

confidence: 99%

“…Binary oxides and Cu-decorated binary oxides of TiO 2 -ZrO 2 have been investigated as TiO 2 -based composites [27]. Doping TiO 2 with cations [28] and more recently with FeOx increase the absorption of light in the visible region enhancing the bacterial inactivation under sunlight irradiation [29].…”

Section: Introductionmentioning

confidence: 99%

Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

Rtimi

Giannakis

Bensimon

et al. 2016

Applied Catalysis B: Environmental

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“…10a/b. The CuO presents a band-gap (of 1.7 eV), cb (−0.3 eV) and vb (+1.7 eV), while direct band-gap of Cu 2 O (p-type) presents a band-gap of (2.1 eV), cb (−1.4 eV) and vb (+0.6 eV) [31][32][33].…”

Section: X-ray Photoelectron Spectroscopy (Xps) and Evidence For Redomentioning

confidence: 99%

“…Because of its unique electronic structure, magnetic and optical properties, Cu 2 O has been used in catalysis/photocatalysis [29] and in solar energy conversion into electrical energy [30][31][32]. Films made-up by Cu and Cu-TiO 2 co-sputtered or sequential sputtered have been reported by our laboratory during the last few years [33][34][35][36][37]. Surface modifications of TiO 2 films incorporating Ag in the dark and under light as antibacterial agent have been widely reported by Cushnie et al [38] and Dias [39].…”

Section: Introductionmentioning

confidence: 99%

Insight into the catalyst/photocatalyst microstructure presenting the same composition but leading to a variance in bacterial reduction under indoor visible light

Rtimi

Pulgarín

Robyr

et al. 2017

Applied Catalysis B: Environmental

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a b s t r a c tInsight into two different uniform atomic-scale microstructures of Cu-and Ti-oxides sputtered on polyethylene (PET) presenting different redox properties and a distinct bacterial inactivation dynamics. Co-sputtered (CuOx-TiO 2 -PET) consists mainly of CuO. It leads to bacterial inactivation kinetics within 20 min under very low intensity actinic light (0.5 mW/cm 2 ). The sequential sputtered (CuOx/TiO 2 -PET) consist mainly of Cu 2 O and led to bacterial inactivation within 90 min. Evidence for redox catalysis is present leading to bacterial inactivation by X-ray photoelectron spectroscopy (XPS). The Cu and Ti uniform distribution on the catalyst surface was mapped along the coating thickness by wavelength dispersive spectrometry (WDS). The inactivation time of E. coli determined by fluorescence stereomicroscopy was in agreement with the time found by agar plating. The short-lived transient intermediates on the cosputtered catalyst were followed by laser spectroscopy in the femto/picosecond region (fs-ps). By atomic force microscopy (AFM) the roughness of the co-sputtered (CuO) and sequentially sputtered samples (Cu 2 O) were found respectively as 1.63 nm and 22.92 nm. The magnitude of the roughness was correlated with the bacterial inactivation times for both types of catalysts. The differentiated mechanisms for the vectorial charge transfer on co-sputtered and sequential sputtered CuOx/TiO 2 catalysts and it is suggested as one of the factors leading to a distinct bacterial inactivation kinetics.

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“…In the TiO2 semiconductor, the irradiation with solar simulated light in the cavity of the solar simulator has been suggested to transfer e − and h + from TiO2 to CuO. Charge transfer from ad-atoms to TiO2 under light has been investigated for the last three decades [167]. The potential energy levels of the TiO2cb and TiO2vb lie above the CuOcb and CuOvb levels, as shown in Figure 11.…”

Section: Coated Polyester (Pes) Films Sputtered By Dcms/dcmsp Inmentioning

confidence: 99%

Recent Developments in Accelerated Antibacterial Inactivation on 2D Cu-Titania Surfaces under Indoor Visible Light

2017

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This review focuses on Cu/TiO 2 sequentially sputtered and Cu-TiO 2 co-sputtered catalytic/photocatalytic surfaces that lead to bacterial inactivation, discussing their stability, synthesis, adhesion, and antibacterial kinetics. The intervention of TiO 2 , Cu, and the synergic effect of Cu and TiO 2 on films prepared by a colloidal sol-gel method leading to bacterial inactivation is reviewed. Processes in aerobic and anaerobic media leading to bacterial loss of viability in multidrug resistant (MDR) pathogens, Gram-negative, and Gram-positive bacteria are described. Insight is provided for the interfacial charge transfer mechanism under solar irradiation occurring between TiO 2 and Cu. Surface properties of 2D TiO 2 /Cu and TiO 2 -Cu films are correlated with the bacterial inactivation kinetics in dark and under light conditions. The intervention of these antibacterial sputtered surfaces in health-care facilities, leading to Methicillin-resistant Staphylococcus Aureus (MRSA)-isolates inactivation, is described in dark and under actinic light conditions. The synergic intervention of the Cu and TiO 2 films leading to bacterial inactivation prepared by direct current magnetron sputtering (DCMS), pulsed direct current magnetron sputtering (DCMSP), and high power impulse magnetron sputtering (HIPIMS) is reported in a detailed manner.

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Heterogeneous photocatalysis. Dynamics of charge transfer in lithium-doped anatase-based catalyst powders with enhanced water photocleavage under ultraviolet irradiation

Cited by 67 publications

References 0 publications

Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

Insight into the catalyst/photocatalyst microstructure presenting the same composition but leading to a variance in bacterial reduction under indoor visible light

Recent Developments in Accelerated Antibacterial Inactivation on 2D Cu-Titania Surfaces under Indoor Visible Light

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