Band Gap Implications on Nano-TiO2 Surface Modification with Ascorbic Acid for Visible Light-Active Polypropylene Coated Photocatalyst

D’Amato, Chiara Anna; Giovannetti, Rita; Zannotti, Marco; Rommozzi, Elena; Minicucci, Marco; Gunnella, R.; Cicco, Andrea Di

doi:10.3390/nano8080599

Cited by 50 publications

(36 citation statements)

References 45 publications

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“…A band gap of Eg ≈ 2.65 eV was derived from the solution by extrapolating the linear portion of the curve in Figure S1 to zero absorption. The modification of CdS NPs with Au NPs slightly reduces the Eg values, proving the photocatalytic activity [37]. The maximum of CdS NPs emission appears at 508 nm.…”

Section: Resultsmentioning

confidence: 81%

Functional CdS-Au Nanocomposite for Efficient Photocatalytic, Photosensitizing, and Two-Photon Applications

et al. 2020

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We demonstrate a low-temperature synthesis of hydrophilic, penicillamine-stabilized hybrid CdS-Au nanoparticles (NPs) utilizing different Au concentrations. The obtained hybrid nanomaterials exhibit photoluminescence quenching and emission lifetime reduction in comparison with their raw semiconductor CdS NPs counterparts. An increase of concentration of Au present at the surface of CdS leads to lower photoluminescence intensity and faster emission decays, suggesting more efficient charge separation when larger Au domains are present. For photocatalysis studies, we performed methylene blue (MB) absorption measurements under irradiation in the presence of CdS-Au NPs. After 1 h of light exposure, we observed the absorbance decrease to about 35% and 10% of the initial value for the CdS-5Au and CdS-7.5Au (the hybrid NPs obtained in a presence of 5.0 and 7.5 mM Au), respectively, which indicates MB reduction caused by electrons effectively separated from holes on metal surface. In further similar photocatalysis experiments, we measured bovine serum albumin (BSA) integrated photoluminescence intensity quenching in the presence of CdS-Au NPs, with a 50% decrease being obtained for CdS-2.5Au NPs and CdS-5Au NPs, with a faster response rate detected for the system prepared with a higher Au concentration. The results suggest hole-driven reactive oxygen species (ROS) production, causing BSA degeneration. Finally, we performed two-photon excited emission (TPEE) measurements for CdS-5Au NPs, obtaining their two-photon absorption (TPA) cross-section values up to 15.8 × 103 GM (Goeppert-Mayer units). We conclude that the obtained water-soluble CdS-Au NPs exhibit potential triple functionalities as photocatalysts for reduction and oxidation reactions as well as materials for two-photon absorption applications, so that they may be considered as future theranostics.

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Section: Resultsmentioning

confidence: 81%

Functional CdS-Au Nanocomposite for Efficient Photocatalytic, Photosensitizing, and Two-Photon Applications

et al. 2020

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“…Therefore, the ratio of anatase to rutile in mixed phase is estimated to be 83:17, which is close to Degussa P25 (80:20). The measurement of band gap is based on the method of reference [24]. The calculated E g of these samples are 3.07, 3.01, and 3.03 eV (Tauc plots of the transformed Kubelka-Munk function vs. the energy, Inset of Figure 1e) of anatase, rutile and mixed phase, respectively.…”

Section: Characterization Of Anatase Rutile and Mixed Phasementioning

confidence: 99%

Photocatalytic Degradation of Atenolol by TiO2 Irradiated with an Ultraviolet Light Emitting Diode: Performance, Kinetics, and Mechanism Insights

Ran

Wang

Fang³

et al. 2019

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Batch experiments were performed to investigate the effect of several environmental factors on atenolol (ATL) degradation efficiency, including catalyst crystal phase (anatase TiO 2 , rutile TiO 2 , and mixed phase), catalyst dosage, UV-LED wavelength and intensity, co-existing anions, cations, and pH. The mixed phase (2 g/L) exhibited the best photocatalytic activity at 365 nm, with ATL (18.77 µM) completely oxidized within 1 h. These results suggest that: (i) The mixed phase exhibits the highest activity due to its large specific surface area and excellent charge separation efficiency.(ii) ATL can be effectively degraded using mixed phase TiO 2 combined with UV-LED technology and the ATL degradation efficiency could reach 100% for 60 min; (iii) ATL photodegradation was more effective under 365 nm UV-LED than 254 nm, which was caused by the effect of light-induced charge separation; (iv) the ATL Degradation efficiency(De) decreased with an increase in initial ATL concentrations; and (v) co-existing anions and cations had different effects on the ATL De, mainly by changing the concentration of hydroxyl radicals. Considering that UV-LED is more energy-saving and environmentally friendly, and commercial TiO 2 is cheap and easy to obtain, our research provides feasibility for practical application.

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“…In the UV/VIS DRS spectra, h-TiO 2 showed absorption of visible light, which indicates the presence of Ti(III) and Ti atoms with even lower oxidation numbers (Supporting Information 2). The optical band gap of bare TiO 2 and h-TiO 2 were determined using Kubelka-Munk method [32,33], and they are 3.2 and 3.1 eV, respectively (Supporting Information 2). However, this was not verified by the Ti 2p spectra in XPS.…”

Section: Characterizations Of Samplesmentioning

confidence: 99%

Surface Modification of TiO2 for Obtaining High Resistance against Poisoning during Photocatalytic Decomposition of Toluene

et al. 2018

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Titanium oxide (TiO2) nanostructures, the most widely used photocatalysts, are known to suffer from poisoning of the active sites during photocatalytic decomposition of volatile organic compounds. Partially oxidized organic compounds with low volatility stick to the catalyst surface, limiting the practical application for air purification. In this work, we studied the UV-driven photocatalytic activity of bare TiO2 toward toluene decomposition under various conditions and found that surface deactivation is pronounced either under dry conditions or humid conditions with a very high toluene concentration (~442 ppm). In contrast, when the humidity was relatively high (~34 %RH) and toluene concentration was low (~66 ppm), such deactivation was not significant. We then modified TiO2 surfaces by deposition of polydimethylsiloxane and subsequent annealing, which yielded a more hydrophilic surface. We provide experimental evidence that our hydrophilic TiO2 does not show deactivation under the conditions that induce significant deactivation with bare TiO2. Conversion of toluene into dimethylacetamide was observed on the hydrophilic TiO2 and did not result in poisoning of active sites. Our hydrophilic TiO2 shows high potential for application in air purification for extended time, which is not possible using bare TiO2 due to the significant poisoning of active sites.

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Band Gap Implications on Nano-TiO2 Surface Modification with Ascorbic Acid for Visible Light-Active Polypropylene Coated Photocatalyst

Cited by 50 publications

References 45 publications

Functional CdS-Au Nanocomposite for Efficient Photocatalytic, Photosensitizing, and Two-Photon Applications

Functional CdS-Au Nanocomposite for Efficient Photocatalytic, Photosensitizing, and Two-Photon Applications

Photocatalytic Degradation of Atenolol by TiO2 Irradiated with an Ultraviolet Light Emitting Diode: Performance, Kinetics, and Mechanism Insights

Surface Modification of TiO2 for Obtaining High Resistance against Poisoning during Photocatalytic Decomposition of Toluene

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