Hybrid mesoporous titania/silica electron-generating and transporting layers were prepared using wet-coating with a dispersion consisting of prefabricated titania nanoparticles and a methyl-silica binder. Titania/methyl-silica wet layers were deposited by inkjet printing and further mineralized by low-temperature atmospheric-pressure air plasma using diffuse coplanar surface barrier discharge (DCSBD) to form a titania/silica hybrid nanocomposite coating. Morphological analysis performed by scanning electron microscopy revealed no damage to the titania nanoparticles and chemical analysis performed by X-ray photoelectron spectroscopy disclosed a rapid decrease in carbon and increase in oxygen, indicating the oxidation effect of the plasma. The coatings were further electrochemically investigated with linear sweep voltammetry and chronoamperometry. The magnitude of photocurrent and photocatalytic activity were found to increase significantly with the plasma exposure on the order of 10s of seconds. The results obtained demonstrate the potential of DCSBD ambient air plasma for fast and low-temperature mineralization of titania mesoporous coatings.
Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)
Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers.
Link to publication
General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ?
Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Titanium dioxide films were grown by atomic layer deposition (ALD) using titanium tetraisopropoxide as a titanium precursor and water, ozone, or oxygen plasma as coreactants. Low temperatures (80-120 C) were used to grow moisture barrier TiO 2 films on polyethylene naphthalate. The maximum growth per cycle for water, ozone, and oxygen plasma processes were 0.33, 0.12, and 0.56 Å /cycle, respectively. X-ray photoelectron spectrometry was used to evaluate the chemical composition of the layers and the origin of the carbon contamination was studied by deconvoluting carbon C1s peaks. In plasma-assisted ALD, the film properties were dependent on the energy dose supplied by the plasma. TiO 2 films were also successfully deposited by using a spatial ALD (SALD) system based on the results from the temporal ALD. Similar properties were measured compared to the temporal ALD deposited TiO 2 , but the deposition time could be reduced using SALD. The TiO 2 films deposited by plasma-assisted ALD showed better moisture barrier properties than the layers deposited by thermal processes. Water vapor transmission rate values lower than 5 Â 10 À4 g day À1 m À2 (38 C and 90% RH) was measured for 20 nm of TiO 2 film deposited by plasma-assisted ALD.
Titania/silica electron-generating and -transporting nanocomposite 300 nm layers of high porosity were deposited onto ITO/PET flexible foils using inkjet printing. Prior to printing, the ITO surface had been modified by novel low-temperature ambient air roll-to-roll plasma in order to enhance its surface properties by removing carbon and oxygen contaminants, a process that led to rapid improvement of surface energy. Consequently the ITO work function, an important parameter involving charge injection efficiency in energy harvesting systems, increased by 1 eV. Afterwards, the TiO 2 /methyl-silica ink exhibited excellent wetting on a 2 s plasma-treated ITO surface. The coating was further processed/mineralized by an additional low-temperature ambient air plasma treatment step. The plasma processing of raw photoanodes led to the mineralization of the methyl-silica binder which resulted in the formation of a fully inorganic TiO 2 /SiO 2 mesoporous structure and significantly increased electrophotocatalytic activity, leading to increased photocurrents. The entire two-step plasma process was performed at low-temperature (70 °C) and high speeds, enabling practical applications of such a procedure for large-area fabrication of flexible photoanodes.
This contribution investigates the effects of duty cycle and mass flow of synthetic air and oxygen on the efficiency of ozone generation in multi-hollow surface dielectric barrier discharge (MSDBD). It discloses that the efficiency of ozone generation in MSDBD is significantly higher compared with standard coplanar DBD, surface DBD and volume DBDs. Ozone production yield reached 205.5 ± 29.1 g (kW h)−1 (40% duty cycle, 8 slm) and 413.91 ± 58.7 g (kW h)−1 (100% duty cycle, 8 slm) at an energy cost of 8.7 and 4.3 eV/molecule for synthetic air and oxygen, respectively. Such high ozone yields arose out of the intrinsic characteristics of MSDBD ceramics, which were efficiently cooled by the flow of the working gas. The amplitude modulation of low-frequency 5 kHz high-voltage sine waveforms facilitates controlled O3 production at a nearly constant rate of yield. Since the correct evaluation of ozone production yield requires precise determination of the discharge power, the concentration of ozone and working gas-flow, considerable attention was paid to measurements of these parameters. It is confirmed and experimentally demonstrated herein that correct determination of discharge power lies with Lissajous figure methods, while the determination of power through the direct integration of product u(t)i(t), where i(t) is measured by Pearson current probe, leads to systematically lower values of calculated power with consequent overestimation of the ozone production yield. The correct determination of discharge power is clearly the key to the proper calculation of ozone production yield and efficiency. Under the DBD discharge conditions presented herein, ozone production yield and efficiency achieved figures as high as 19.5% and 35.2% of theoretical limits recently established for air and oxygen, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.