Suppressing the Photocatalytic Activity of TiO2 Nanoparticles by Extremely Thin Al2O3 Films Grown by Gas-Phase Deposition at Ambient Conditions

Guo, Jing; Valdesueiro, David; Yuan, Shaojun; Liang, Bin; Ommen, J. Ruud van

doi:10.3390/nano8020061

Cited by 37 publications

(21 citation statements)

References 89 publications

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“…Later, a 3 min dose of oxidant precursor followed by a purge with nitrogen of 8 min. Both the reaction temperatures, the number of cycles and the dosing time of each precursor were previously optimized [38].…”

Section: Atomic Layer Depositionmentioning

confidence: 99%

Multitarget Evaluation of the Photocatalytic Activity of P25-SiO2 Prepared by Atomic Layer Deposition

et al. 2020

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This work presents the evaluation of the photocatalytic activity of P25 TiO2 particles, coated with SiO2, using atomic layer deposition (ALD) for the photocatalytic removal of methylene blue, oxidation of methanol and inactivation of Escherichia coli bacteria in water and its comparative evaluation with bare P25 TiO2. Two different reactor configurations were used, a slurry reactor with the catalyst in suspension, and a structured reactor with the catalyst immobilized in macroporous foams, that enables the long-term operation of the process in continuous mode, without the necessity of separation of the particles. The results show that the incorporation of SiO2 decreases the efficiency of the photocatalytic oxidation of methanol, whereas a significant improvement in the removal of methylene blue is achieved, and no significant changes are observed in the photocatalytic inactivation of bacteria. Adsorption tests showed that the improvements, observed in the removal of methylene blue by the incorporation of SiO2, was mainly due to an increase in its adsorption. The improvement in the adsorption step as part of the global photocatalytic process led to a significant increase in its removal efficiency. Similar conclusions were reached for bacterial inactivation where the loss of photocatalytic efficiency, suggested by the methanol oxidation tests, was counteracted with a better adherence of bacteria to the catalyst that improved its elimination. With respect to the use of macroporous foams as support, a reduction in the photocatalytic efficiency is observed, as expected from the decrease in the available surface area. Nevertheless, this lower efficiency can be counteracted by the operational improvement derived from the easy catalyst reuse.

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Section: Atomic Layer Depositionmentioning

confidence: 99%

Multitarget Evaluation of the Photocatalytic Activity of P25-SiO2 Prepared by Atomic Layer Deposition

et al. 2020

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“…ZnO, as one of the inorganic UV-absorbers has been used to formulate UV shielding materials such as sunscreens. Surface modifications such as silica coating [13], impurity doping [14,15], polymer stabilization [16,17], capping agents [18] and metal oxides hetero-composites [1,4,19] have been implemented to tune the photo response properties of ZnO for possible application in reducing the effects of UV absorption.…”

Section: Introductionmentioning

confidence: 99%

Reduction of hazardous reactive oxygen species (ROS) production of ZnO through Mn inclusion for possible UV-radiation shielding application

Lefatshe

Mola

Muiva

2020

Heliyon

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Mn x -ZnO (1-x) nanopowders were successfully synthesised through a simple sol-gel method. The samples were annealed at 300 C to enhance their crystallinity. The lattice structure, morphology and optical properties of the prepared powdered samples were extensively studied using different characterization techniques, confirming the formation of Mn x -ZnO (1-x) . The inclusion of Mn did not cause any change to the wurtzite structure of ZnO; however slight peak shifting and increase in lattice parameters were indicated. The normal absorption spectra pointed to a cut-off edge extending beyond the UV region and a Burstein-Moss type band gap broadening induced by the Mn doping. ZnO showed excellent photodegradation activity against methylene blue (MB) upon UV irradiation. Intensifying the dopant concentration resulted in further diminution of photoactivity against MB. This reduction of photocatalytic activity of ZnO upon doping can be drawn to be due to the presence of Mn in the ZnO lattice, which acted as recombination sites for the photogenerated charge carriers.The results demonstrated that doping ZnO with Mn can be used to suppress the oxidative stress induced by reactive oxygen species (ROS) through generation of recombination centres. The suppression of toxic ROS generation implies possible application in fabrics and ointments for UV shielding applications.

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“…Copper oxides (CuO and Cu 2 O) are well-studied metal oxides for photocathodic hydrogen production because they are natural p-types with proper band gaps for light absorption [ 48 ]. Nano-coating using the atomic layer deposition method was performed with a home-built fluidized bed reactor [ 49 , 50 ]. P25-TiO 2 and a high-grade copper(I) hexafluoropentanedionate–vinyltrimethylsilane complex (Cu(I)(hfac)(TMVS)) [ 51 , 52 , 53 ] were used in the nano-coating process with nitrogen and distilled water [ 54 ].…”

Section: Methodsmentioning

confidence: 99%

Safe-and-Sustainable-by-Design Framework Based on a Prospective Life Cycle Assessment: Lessons Learned from a Nano-Titanium Dioxide Case Study

Tsalidis

Soeteman‐Hernández

Noorlander

et al. 2022

IJERPH

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Safe-and-sustainable-by-design (SSbD) is a concept that takes a systems approach by integrating safety, sustainability, and functionality throughout a product’s the life cycle. This paper proposes a framework based on a prospective life cycle assessment for early safety and sustainability assessment. The framework’s purpose is to identify environmental sustainability and toxicity hotspots early in the innovation process for future SSbD applicability. If this is impossible, key performance indicators are assessed. Environmental sustainability aspects, such as global warming potential (GWP) and cumulative energy demand (CED), and toxicity aspects, such as human toxicity potential and freshwater ecotoxicity potential, were assessed upon applying the framework on a case study. The case study regarded using nano-titanium dioxide (P25-TiO2) or a modified nano-coated version (Cu2O-coated/P25-TiO2) as photocatalysts to produce hydrogen from water using sunlight. Although there was a decrease in environmental impact (GWP and CED), the modified nano-coated version had a relatively higher level of human toxicity and freshwater eco-toxicity. For the presented case study, SSbD alternatives need to be considered that improve the photocatalytic activity but are not toxic to the environment. This case study illustrates the importance of performing an early safety and environmental sustainability assessment to avoid the development of toxic alternatives.

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Suppressing the Photocatalytic Activity of TiO2 Nanoparticles by Extremely Thin Al2O3 Films Grown by Gas-Phase Deposition at Ambient Conditions

Cited by 37 publications

References 89 publications

Multitarget Evaluation of the Photocatalytic Activity of P25-SiO2 Prepared by Atomic Layer Deposition

Multitarget Evaluation of the Photocatalytic Activity of P25-SiO2 Prepared by Atomic Layer Deposition

Reduction of hazardous reactive oxygen species (ROS) production of ZnO through Mn inclusion for possible UV-radiation shielding application

Safe-and-Sustainable-by-Design Framework Based on a Prospective Life Cycle Assessment: Lessons Learned from a Nano-Titanium Dioxide Case Study

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