Bio Nano Consulting Ltd

St. Pancras, United Kingdom

Bio Nano Consulting Ltd

St. Pancras, United Kingdom

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Hamdy M.S.,Bio Nano Consulting Ltd. | Nickels P.,Bio Nano Consulting Ltd. | Abd-Elmaksood I.H.,King Abdulaziz University | Zhou H.,Bio Nano Consulting Ltd. | And 2 more authors.
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2012

Commercial TiO 2 (Hombikat, UV-100) was impregnated with different loadings of zinc nitrate solution and subsequently calcined at different temperatures in order to obtain a stable homogeneous solid composite of ZnO/TiO 2. The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), UV-vis and Raman spectroscopy, inductively coupled plasma mass spectroscopy (ICP), X-ray photoelectron spectroscopy (XPS) as well as N 2 adsorption and desorption measurements. Results show that ZnO was incorporated within the TiO 2 crystals and did not form a separate bulky phase or metallic zinc. Moreover, the calcination temperature dramatically modifies the texture properties of the prepared samples compared with original Hombikat TiO 2. The photocatalytic performance of the prepared samples was evaluated by monitoring the degradation of methyl orange dye under black light illumination. Three main parameters were studied; ZnO loading, surface area and initial pH of the methyl orange solution. The variation in ZnO loading appears to have less influence on the catalytic activity than either the surface area or the pH. © 2011 Elsevier B.V. All rights reserved.


Bhachu D.S.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd | Sankar G.,University College London | And 9 more authors.
Advanced Functional Materials | Year: 2014

This paper reports the synthesis of highly conductive niobium doped titanium dioxide (Nb:TiO2) films from the decomposition of Ti(OEt)4 with dopant quantities of Nb(OEt)5 by aerosol-assisted chemical vapor deposition (AACVD). Doping Nb into the Ti sites results in n-type conductivity, as determined by Hall effect measurements. The doped films display significantly improved electrical properties compared to pristine TiO2 films. For 5 at.% Nb in the films, the charge carrier concentration was 2 × 1021 cm-3 with a mobility of 2 cm2 V-1 s-1. The corresponding sheet resistance is as low as 6.5 Ω sq-1 making the films suitable candidates for transparent conducting oxide (TCO) materials. This is, to the best of our knowledge, the lowest reported sheet resistance for Nb:TiO 2 films synthesized by vapour deposition. The doped films are also blue in colour, with the intensity dependent on the Nb concentration in the films. A combination of synchrotron, laboratory and theoretical techniques confirmed niobium doping into the anatase TiO2 lattice. Computational methods also confirmed experimental results of both delocalized (Ti 4+) and localized polaronic states (Ti3+) states. Additionally, the doped films also functioned as photocatalysts. Thus, Nb:TiO2 combines four functional properties (photocatalysis, electrical conductivity, optical transparency and blue colouration) within the same layer, making it a promising alternative to conventional TCO materials. Solution processing of Nb:TiO2 has presented many challenges to the materials community. Nb:TiO2 made by solution processing has been consigned to sensor/catalysis applications. Here, a solution route is presented to highly conductive and photocatalytically active Nb:TiO2 films. A blue color is observed for the niobium doped films with XPS and computational methods showing a stable localized Ti3+ state at the anatase surface compared to the bulk. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Alotaibi A.M.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd | Parkin I.P.,University College London
RSC Advances | Year: 2015

ZrO2-TiO2 composite thin films were deposited by aerosol assisted chemical vapour deposition onto a glass substrate at 450 °C and then annealed at 600 °C. For comparison ZrO2 thin films and TiO2 thin films were deposited under the same conditions. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV-Vis and Raman spectroscopy were used to characterize all films. Photocatalytic activities were tested by degradation of intelligent ink containing resazurin redox dye under UVA irradiation. The formal quantum efficiency (FQE) and yield (FQY) for the ZrO2-TiO2 composite thin films were determined as 2.03 × 10-3 dye molecules per incident photon and 4.91 × 10-3 dye molecules per absorbed photon respectively. Surprisingly the ZrO2-TiO2 composite was a more efficient photocatalyst than the comparable TiO2 coating. This journal is © The Royal Society of Chemistry.


Ponja S.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd. | Chadwick N.,University College London | And 7 more authors.
Journal of Materials Chemistry A | Year: 2013

Aerosol assisted chemical vapour deposition (AACVD) was used to synthesise a TiO2-SnO2 composite film onto a glass substrate. For comparison a TiO2 film and a SnO2 film were also prepared. All films were characterised by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and wavelength dispersive X-ray spectroscopy (WDX). XPS and WDX of the composite film revealed a TiO2 rich film with a high level of SnO2 segregation at the surface. Highly structured pyramid-like features gave rise to hydrophobic films with static water contact angles of 134°. Photocatalytic activities were determined by monitoring the degradation of intelligent ink (containing Resazurin redox dye) via UV-visible spectroscopy. Under UVA irradiation, the TiO2 film only began to degrade the dye after being irradiated in excess of 100 minutes, whereas the composite TiO 2-SnO2 film required only 6 minutes of irradiation before degradation was observed. The formal quantum efficiency (FQE) for the TiO 2-SnO2 composite was determined to be 1.01 × 10 -2 molecules per incident photon and the formal quantum yield (FQY) was 1.17 × 10-2 molecules per absorbed photon. This is an order of magnitude superior to Pilkington Activ™ self-cleaning glass a commercial self-cleaning TiO2 coating on glass. This improved photocatalytic activity is attributed to the presence of electron scavenging SnO2 sites that increase charge separation and the increased surface area due to the highly structured morphology. © 2013 The Royal Society of Chemistry.


Chadwick N.,University College London | Sathasivam S.,Bio Nano Consulting Ltd | Kafizas A.,University College London | Bawaked S.M.,King Abdulaziz University | And 5 more authors.
Journal of Materials Chemistry A | Year: 2014

Combinatorial Aerosol Assisted Chemical Vapour Deposition (cAACVD) was used to grow a thin film that graduated across its width from tin dioxide to titanium dioxide. This is a relatively new technique that can be used to create a variety of mixed phase and composition thin films on a single substrate. Here cAACVD was used to deposit a mixed phase TiO2 and SnO2 film and composition was related to UV photocatalysis, hydrophobicity and microstructure not inherent to anatase TiO2 or cassiterite SnO 2. Characterisation was achieved using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and UV-Vis spectroscopy. Functional testing to elucidate the differences in functional properties across the film was undertaken by the photo-induced degradation of a resazurin 'intelligent' ink, a photo-induced wettability study and two-point resistivity measurements. Functional properties showed enhanced photocatalysis in comparison to Pilkington Activ™ with similar formal quantum yield (molecules destroyed per absorbed photon) and formal quantum efficiency (molecules destroyed per incident photon) values. This journal is © the Partner Organisations 2014.


Bawaked S.M.,King Abdulaziz University | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd. | Bhachu D.S.,University College London | And 6 more authors.
Journal of Materials Chemistry A | Year: 2014

This paper shows the aerosol assisted chemical vapour deposition of transparent, blue coloured and conductive tantalum doped titanium dioxide films from the CVD reaction of Ti(OEt)4 and Ta(OEt)5. Hall effect measurements showed the doped films to have excellent n-type electrical conductivity showing, to the best of our knowledge, the lowest reported sheet resistance ever recorded for Ta-doped TiO2 of 14 Ω sq -1. The Ta 6 atom% doped TiO2 film also showed the best electrical results with a charge carrier concentration of 1.60 × 10 21 cm-3 and mobility of 1.44 cm2 V-1 s-1 making it a suitable electrode in photovoltaic devices. The doped films were multifunctional, showing good photocatalytic activity under UV-light illumination. XPS and XRD studies gave strong evidence that the Ta was entering the TiO2 lattice as Ta5+ and that a reduction of some Ti4+ to Ti3+ was observed. © 2014 the Partner Organisations.


Ponja S.D.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd | Davies H.O.,ACAL Energy | And 2 more authors.
ChemPlusChem | Year: 2016

Aerosol-assisted chemical vapour deposition of substituted polyoxometalates H4[PMo11VO40], H7[PMo8V4O40], [nBu4N]4[PVW11O40] and [nBu4N]5[PV2W10O40] resulted in the formation of vanadium-doped metal oxide thin films. Depositions were carried out at 550 °C in methanol or acetonitrile for the POMs that contained molybdenum or tungsten, respectively. The as-deposited films were X-ray amorphous and relatively non-adherent. However, on annealing in air at 600 °C, decolourised translucent films that were more mechanically robust were obtained. Films deposited from H4[PMo11VO40] and H7[PMo8V4O40] consisted of V-doped MoO3 in the orthorhombic phase and films from [nBu4N]4[PVW11O40] and [nBu4N]5[PV2W10O40] comprised of monoclinic V-doped WO3. All films were fully characterised by using X-ray photoelectron spectroscopy, energy-dispersive X-ray diffraction, scanning electron microscopy and UV/Vis spectroscopy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bhachu D.S.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd. | Carmalt C.J.,University College London | Parkin I.P.,University College London
Langmuir | Year: 2014

PbO clusters were deposited onto polycrystalline titanium dioxide (anatase) films on glass substrates by aerosol-assisted chemical vapor deposition (AACVD). The as-deposited PbO/TiO2 films were then tested for visible light photocatalysis. This was monitored by the photodegradation of stearic acid under visible light conditions. PbO/TiO2 composite films were able to degrade stearic acid at a rate of 2.28 × 1015 molecules cm-2 h-1, which is 2 orders of magnitude greater than what has previously been reported. The PbO/TiO2 composite film demonstrated UVA degradation of resazurin redox dye, with the formal quantum yield (FQY) and formal quantum efficiency (FQE) exceeding that of a TiO 2 film grown under the same conditions and Pilkington Activ, a commercially available self-cleaning glass. This work correlates with computational studies that predicted PbO nanoclusters on TiO2 form active visible light photocatalysts through new electronic states through PbO/TiO2 interfacial bonds resulting in new electronic states above the valence band maximum in TiO2, shifting the valence band upward as well as more efficient electron/hole separation with hole localization on PbO particles and electron on the TiO2 surface. © Published 2013 by the American Chemical Society.


Paulauskas I.E.,Bio Nano Consulting Ltd. | Paulauskas I.E.,University College London | Modeshia D.R.,Bio Nano Consulting Ltd. | Ali T.T.,King Abdulaziz University | And 5 more authors.
Platinum Metals Review | Year: 2013

The photocatalytic activities of a series of titanium dioxide (TiO 2) based nanoparticles, synthesised via flame spray pyrolysis (FSP), have been investigated and compared with the commercially available Evonik Aeroxide® TiO2 P 25 (P 25). The effects of metal ions aluminium, tin and platinum, respectively, on the physical and chemical properties of the TiO2 nanoparticles are reported. The set of six samples were characterised by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma-mass spectrometry (ICP-MS) and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. Specific surface areas were determined using nitrogen adsorption and desorption measurements. Subsequent photocatalytic studies of the degradation of methyl orange (MO) dye under UV irradiation demonstrated that addition of Al and Sn had a negative effect on catalytic performance, whereas the addition of ≤ 0.7 at% Pt to each sample enhanced photocatalytic activity. Most interestingly, the Pt-doped composite samples (TiO2-Sn/Pt and TiO2-Al/Pt) both showed a significantly higher rate of degradation of MO, when compared to P 25. All Pt-doped samples show an increased visible photon absorption capacity. The relationships between the physical and chemical characteristics are discussed in relation to photocatalytic performance. © 2013 Johnson Matthey.


Alotaibi A.M.,University College London | Sathasivam S.,University College London | Sathasivam S.,Bio Nano Consulting Ltd | Nair S.P.,University College London | Parkin I.P.,University College London
Journal of Materials Chemistry B | Year: 2016

The antibacterial properties of a Cu-ZrO2 film grown via aerosol assisted chemical vapour deposition are presented. The composite film showed high activity against E. coli (Gram-negative) and S. aureus (Gram-positive) bacteria with 5 log10 (E. coli) and 4 log10 (S. aureus) decrease in viable bacteria achieved within 20 and 60 minutes respectively. These results were comparable to a pure copper film that was prepared under the same conditions. The composite film was characterized for material properties using a range of techniques including X-ray photoemission and X-ray diffraction. © 2015 The Royal Society of Chemistry.

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