scholarly journals Improved Catalytic Durability of Pt-Particle/ABS for H2O2 Decomposition in Contact Lens Cleaning

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 342 ◽  
Author(s):  
Yuji Ohkubo ◽  
Tomonori Aoki ◽  
Satoshi Seino ◽  
Osamu Mori ◽  
Issaku Ito ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Charge ◽  
Contact Lens ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Pt Nanoparticles ◽  
Acrylonitrile Butadiene Styrene ◽  
Atomic Emission ◽  
Cross Sectional ◽  
H2o2 Decomposition

In a previous study, Pt nanoparticles were supported on a substrate of acrylonitrile–butadiene–styrene copolymer (ABS) to give the ABS surface catalytic activity for H2O2 decomposition during contact lens cleaning. Although the Pt-particle/ABS catalysts exhibited considerably high specific catalytic activity for H2O2 decomposition, the catalytic activity decreased with increasing numbers of repeated usage, which meant the durability of the catalytic activity was low. Therefore, to improve the catalytic durability in this study, we proposed two types of pretreatments, as well as a combination of these treatments before supporting Pt nanoparticles on the ABS substrate. In the first method, the ABS substrate was etched, and in the second method, the surface charge of the ABS substrate was controlled. A combination of etching and surface charge control was also applied as a third method. The effects of these pretreatments on the surface morphology, surface chemical composition, deposition behavior of Pt particles, and Pt loading weight were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), cross-sectional SEM, and inductively coupled plasma atomic emission spectroscopy (ICP-AES), respectively. Both etching and controlling the surface charge effectively improved the catalytic durability for H2O2 decomposition. In addition, the combination treatment was the most effective.

scholarly journals Strong Biomimetic Immobilization of Pt-Particle Catalyst on ABS Substrate Using Polydopamine and Its Application for Contact-Lens Cleaning with H2O2

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 114 ◽  
Author(s):  
Yuji Ohkubo ◽  
Tomonori Aoki ◽  
Daisuke Kaibara ◽  
Satoshi Seino ◽  
Osamu Mori ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Contact Lens ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Acrylonitrile Butadiene Styrene ◽  
Atomic Emission ◽  
H2o2 Concentration ◽  
H2o2 Decomposition ◽  
Inductively Coupled ◽  
Considerable Problem

Polydopamine (PDA)—a known adhesive coating material—was used herein to strongly immobilize a Pt-particle catalyst on an acrylonitrile–butadiene–styrene copolymer (ABS) substrate. Previous studies have shown that the poor adhesion between Pt particles and ABS surfaces is a considerable problem, leading to low catalytic durability for H2O2 decomposition during contact-lens cleaning. First, the ABS substrate was coated with PDA, and the PDA film was evaluated by X-ray photoelectron spectroscopy. Second, Pt particles were immobilized on the PDA-coated ABS substrate (ABS-PDA) using the electron-beam irradiation reduction method. The Pt particles immobilized on ABS-PDA (Pt/ABS-PDA) were observed using a scanning electron microscope. The Pt-loading weight was measured by inductively coupled plasma atomic emission spectroscopy. Third, the catalytic activity of the Pt/ABS-PDA was evaluated as the residual H2O2 concentration after immersing it in a 35,000-ppm H2O2 solution (the target value was less than 100 ppm). The catalytic durability was evaluated as the residual H2O2 concentration after repeated use. The PDA coating drastically improved both the catalytic activity and durability because of the high Pt-loading weight and strong adhesion among Pt particles, PDA, and the ABS substrate. Plasma treatment prior to PDA coating further improved the catalytic durability.

scholarly journals Protection of LiFePO4 against Moisture

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 942 ◽  
Author(s):  
Nicolas Delaporte ◽  
Michel L. Trudeau ◽  
Daniel Bélanger ◽  
Karim Zaghib
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Carbon Surface ◽  
Water Contact ◽  
Inductively Coupled ◽  
Spontaneous Reduction ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Carbon Coated

In this study, a carbon-coated LiFePO4 (LFP/C) powder was chemically grafted with trifluoromethylphenyl groups in order to increase its hydrophobicity and to protect it from moisture. The modification was carried out by the spontaneous reduction of in situ generated 4-trifluoromethylphenyl ions produced by the diazotization of 4-trifluoromethylaniline. X-ray photoelectron spectroscopy was used to analyze the surface organic species of the modified powder. The hydrophobic properties of the modified powder were investigated by carrying out its water contact angle measurements. The presence of the trifluoromethylphenyl groups on the carbon-coated LiFePO4 powder increased its stability in deionized water and reduced its iron dissolution in the electrolyte used for assembling the battery. The thermogravimetric and inductively coupled plasma atomic emission spectroscopy analyses revealed that 0.2–0.3 wt.% Li was deinserted during grafting and that the loading of the grafted molecules varied from 0.5 to 0.8 wt.% depending on the reaction conditions. Interestingly, the electrochemical performance of the modified LFP/C was not adversely affected by the presence of the trifluoromethylphenyl groups on the carbon surface. The chemical relithiation of the grafted samples was carried out using LiI as the reducing agent and the lithium source in order to obtain fully lithiated grafted powders.

Photocatalytic Oxidation of Alcohols Over Magnetically Recoverable Gold Supported Iron Oxide Nanoparticles

2019 ◽  
Vol 11 (12) ◽  
pp. 1731-1738 ◽  
Author(s):  
Ma Hui ◽  
Wu Juzhen ◽  
Zhao Li ◽  
Zhou Zheng ◽  
Guo Jiahu
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Photocatalytic Oxidation ◽  
Organic Dyes ◽  
Atomic Emission ◽  
One Pot ◽  
X Ray ◽  
Inductively Coupled ◽  
Oxidation Of Alcohols

A one-pot simple and efficient synthetic route for the synthesis of Au-loaded Fe2O3 nanoparticles was developed, and this material's photocatalytic activity for visible light assisted oxidation of alcohols and degradation of organic dye were studied. As-synthesized nanostructured catalyst was characterised by powder X-ray diffraction (XRD), transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM-mapping, X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherm (BET), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). It was observed that 5–10 nm Au-nanoparticles supported on 10–80 nm Fe2O3 shows boomerang-shaped nanoparticle. Gold loading of 1 wt% shows high conversion and selectivity towards the target product aldehyde. The synthesized nanomaterial also proved to be an excellent photocatalyst for degradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB). The catalyst proved to be noteworthy as it does not loss in its catalytic activity even after five cycles of reuse.

Antiphotocorrosive photocatalysts containing CdS nanoparticles and exfoliated TiO2 nanosheets

2010 ◽  
Vol 25 (1) ◽  
pp. 182-188 ◽  
Author(s):  
Xiaoxia Yan ◽  
Gang Liu ◽  
Lianzhou Wang ◽  
Yong Wang ◽  
Xianfang Zhu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Cds Nanoparticles ◽  
Visible Absorption ◽  
X Ray ◽  
Tio2 Nanosheets

Aimed at designing an efficient visible light active photocatalyst and suppressing the self-corrosion tendency of CdS nanoparticles, a novel composite consisting of CdS nanoparticles and exfoliated two-dimensional (2D) TiO2 nanosheets was successfully fabricated using a simple self-assembly process. The prepared samples were characterized using various techniques including x-ray diffraction, ultraviolet–visible absorption spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that the exfoliated 2D nanosheets played an important role as an ultrathin coating to suppress the photocorrosion of CdS nanoparticles, evidenced by inductively coupled plasma-atomic emission spectrometer analysis. The resultant CdS/TiO2 composites exhibited enhanced photocatalytic activity in the oxidation of Rhodamine B in water under visible light irradiation (λ > 420 nm).

scholarly journals Occupational Exposure to Nickel in the Ceramic Workers: Biological Monitoring and Respiratory Outcomes

2020 ◽  
Author(s):  
Fatemeh Kargar-Shouroki ◽  
Seyed Jamaleddin Shahtaheri ◽  
Abolfazl Barkhordari ◽  
Niloofar Halvani
Keyword(s):  
Pulmonary Function ◽  
Inductively Coupled Plasma ◽  
Solid Phase ◽  
Ventilation System ◽  
Atomic Emission ◽  
Exposed Group ◽  
Respiratory Protection ◽  
Cross Sectional ◽  
Referent Group ◽  
Ceramic Workers

Background: Nickel (Ni) compounds such as nickel oxide are used as pigments in ceramic industries. The toxicity of nickel can occur in the glaze preparation processes. This study aimed to ascertain whether exposure to Ni dust is associated with pulmonary response. Methods: This cross-sectional study was performed on 49 ceramic workers (exposed group) occupationally exposed to nickel dust, as well as 55 unexposed employees (referent group). Information about smoking habits, overtime work, length of employment, skin dermatitis, job title, use of respiratory protection equipment, ventilation system, age, and BMI index were collected through questionnaires. The parameters of pulmonary function were measured. Urine samples were taken from 49 workers at both pre- and post-shift (98 samples). The referent group was examined only once (55 samples). To determine the nickel, the samples were pre-concentrated by Solid Phase Extraction (SPE) and analyzed using  inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Results: Urinary Ni value in the exposed workers was significantly higher than that in the referent group. All pulmonary function parameters in the exposed group were significantly lower than those of the referent group (P<0.001). Those using respiratory protection equipment also exhibited a significantly lower urinary Ni concentration than those not using respiratory protection equipment. Conclusion: These findings indicate that exposure to Ni in the ceramic industry is higher than the recommended biological exposure index and is associated with a significant decrement in the pulmonary function parameters.

scholarly journals From Bulk to Atoms: The Influence of Particle and Cluster Size on the Hydrogen Evolution Reaction

2020 ◽  
Vol 234 (5) ◽  
pp. 847-865 ◽  
Author(s):  
Florian Neuberger ◽  
Julian Baranyai ◽  
Torben Schmidt ◽  
Thorsten Cottre ◽  
Bernhard Kaiser ◽  
...  
Keyword(s):  
Particle Size ◽  
Catalytic Activity ◽  
Band Gap ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Cluster Size ◽  
Pt Nanoparticles ◽  
Binding Energies ◽  
Clear Correlation

AbstractTo investigate the influence of particle size in terms of electrocatalysis for the hydrogen evolution reaction (HER), small Ptn species with $n=1,10,13$ atoms and nanoparticles are deposited onto native titanium dioxide. These species are compared to the bare support as well as to bulk platinum with respect to the catalytic activity. Photoelectron spectroscopy showed Pt4f core-level shifts to higher binding energies with decreasing cluster size. In addition, the various species contribute significant density of states into the valence band gap of TiO2, thereby with larger particle size, the resulting band gap narrows. For nanoparticles, metal-like behaviour was already observed. Electrochemical measurements in 0.1 M H2SO4 showed the highest overall catalytic activity for bulk platinum and large Pt nanoparticles. A different assertion is obtained when the activities are related to the mass of the catalyst used, indicating that clusters with a size of about ten atoms seem to be most active. In comparison with the results from photoelectron spectroscopy regarding the electronic structure, no clear correlation to the catalytic activity was found. In terms of degradation induced due to the electrochemical treatment, the cluster samples showed no sintering effects, but instead, some detachment took place.

scholarly journals The Modification of Pt/Graphene Composites with Oxophilic Metal Bi (Bi2O3) and Its Dual-Functional Electro-Photo Catalytic Performance

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 465
Author(s):  
Yingli Wu ◽  
Xiuyun Duan ◽  
Zhongshui Li ◽  
Shuhong Xu ◽  
Yixin Xie ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Electric Energy ◽  
Atomic Emission ◽  
Catalytic Performance ◽  
Water Soluble ◽  
Methanol Oxidation Reaction ◽  
Solution Synthesis ◽  
X Ray ◽  
Electrocatalytic Properties

The Pt-Bi (Bi2O3)/GNs (PVP) composite was synthesized using aqueous solution synthesis and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Raman spectroscopy. It was found that the water-soluble polyvinyl pyrrolidone (PVP) helped to tune the particles’ morphology, resulting in a uniform distribution of Pt-Bi nanoclusters on the surface of graphene. Cyclic voltammetry, chronoamperometry and linear scanning voltammetry (LSV) were used to study the electrocatalytic properties towards a methanol oxidation reaction (MOR) and an oxygen reduction reaction (ORR). The results show that Pt-Bi (Bi2O3)/GNs (PVP) exhibits superior bifunctional electrocatalytic properties for both MOR and ORR, mainly due to the introduction of oxophilic Bi species and the better dispersion of the Pt-Bi nanoclusters. In particular, the electro-photo catalysis for both MOR and ORR occurred under simulated sunlight irradiation due to the existence of photo-responsive Bi species, which is helpful for converting solar energy into electric energy during a traditional electrocatalytic process.

scholarly journals Transition Metal Oxodiperoxo Complex Modified Metal-Organic Frameworks as Catalysts for the Selective Oxidation of Cyclohexane

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 829 ◽  
Author(s):  
Yuechao Hong ◽  
Jie Peng ◽  
Zhichao Sun ◽  
Zhiquan Yu ◽  
Anjie Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Metal Organic Frameworks ◽  
Atomic Emission ◽  
Cyclohexane Oxidation ◽  
Metal Species ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission Spectrometry ◽  
Metal Organic

In this work, a series of modified metal-organic frameworks (MOFs) have been prepared by pre- and post-treatment with transition metal oxodiperoxo complexes (MoO(O2)2, WO(O2)2, and KVO(O2)2). The obtained materials are characterized by XRD, FTIR, SEM, TEM, inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS), as well as by N2 adsorption/desorption measurement. The characterization results show that transition metal oxodiperoxo complexes are uniformly incorporated into the MOF materials without changing the basic structures. The performance of cyclohexane oxidation on metal oxodiperoxo complex modified MOFs are evaluated. UiO-67-KVO(O2)2 shows the best performance for cyclohexane oxidation, with 78% selectivity to KA oil (KA oil refers to a cyclohexanol and cyclohexanone mixture) at 9.4% conversion. The KA selectivity is found to depend on reaction time, while hot-filtration experiments indicates that the catalytic process is heterogeneous with no leaching of metal species.

scholarly journals Probing the charging mechanisms of carbon nanomaterial polyelectrolytes

2014 ◽  
Vol 172 ◽  
pp. 311-325 ◽  
Author(s):  
Stephen A. Hodge ◽  
Hui Huang Tay ◽  
David B. Anthony ◽  
Robert Menzel ◽  
David J. Buckley ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Chemical Reactivity ◽  
Atomic Emission ◽  
Metal Nanoparticle ◽  
Redox Activity ◽  
Processing Route ◽  
Future Research ◽  
Great Promise ◽  
Electronic Density

Chemical charging of single-walled carbon nanotubes (SWCNTs) and graphenes to generate soluble salts shows great promise as a processing route for electronic applications, but raises fundamental questions. The reduction potentials of highly-charged nanocarbon polyelectrolyte ions were investigated by considering their chemical reactivity towards metal salts/complexes in forming metal nanoparticles. The redox activity, degree of functionalisation and charge utilisation were quantified via the relative metal nanoparticle content, established using thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The fundamental relationship between the intrinsic nanocarbon electronic density of states and Coulombic effects during charging is highlighted as an important area for future research.

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