The Strategy for Constructing the Structure: Pt-O-Ce3+ Applied in Efficient NOx Removal

Exploring a unique structure with superior catalytic performance has remained a severe challenge in many important catalytic reactions. Here, we reported a phenomenon that CeO2-based catalysts loaded with different Pt precursors showed a significant difference in the performance of the reduction of NO with H2. The supported platinum nitrate [PtCe(N)] exhibited a superior low-temperature catalytic performance than the supported chloroplatinic acid [PtCe(C)]. In a wide operating temperature (125–200°C), more than 80% NOx conversion was achieved over PtCe(N) as well as excellent thermal stability. Various characterizations were used to study the microstructure and chemical electronic states. Results showed the introduction of a low valence state of Pt species into the CeO2 resulted in the rearrangement of charges on the surface of CeO2, accompanied by increasing contents of oxygen vacancies and Ce3+ sites. Furthermore, the X-ray photoelectron spectroscopy (XPS) and Raman spectra confirmed that the divalent Pt atom could substitute Ce atom to form the Pt-O-Ce3+ structure, which was the base unit in the high-performance PtCe(N) catalyst. The tunable catalytic system of the Pt-O-Ce3+ structure provides a strategy for the design of supported metal catalysts and may as a model unit for future studies of many other reactions.

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The Electronic Interaction of Pt-Clusters with ITO and HOPG Surfaces upon Water Adsorption

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2013-0499 ◽

2014 ◽

Vol 228 (4-5) ◽

Cited By ~ 6

Author(s):

Joachim Klett ◽

Stephan Krähling ◽

Benjamin Elger ◽

Rolf Schäfer ◽

Bernhard Kaiser ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Efficiency ◽

Catalytic Performance ◽

Substrate Material ◽

Binding Energies ◽

Electronic Interaction ◽

Support Materials ◽

Platinum Cluster ◽

Supported Platinum ◽

Platinum Clusters

AbstractIn order to investigate the catalytic properties of supported platinum clusters, their interaction with water was monitored using photoelectron spectroscopy. The clusters were exposed to up to five Langmuir of water at cryogenic temperatures. Additionally, the influence of the substrate was studied by employing HOPG and ITO as complementary support materials. In contrast to bulk platinum a distinct chemical shift is observable in the Pt4f binding energies for Pt clusters deposited on ITO. The same clusters on HOPG show no changes in binding energy. We propose that this trend is due to a change in the surface Fermi level in ITO, hence highlighting the strong interaction between the platinum cluster and the substrate material. Therefore it is reasonable to assume, that the catalytic efficiency of these clusters in general can not solely be described by the electronic structure of the cluster alone, but that also the electronic changes induced in the substrate may have a major impact on the catalytic performance as well.

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Oscillatory Behavior of Pd-Au Catalysts in Toluene Total Oxidation

Catalysts ◽

10.3390/catal8120574 ◽

2018 ◽

Vol 8 (12) ◽

pp. 574 ◽

Cited By ~ 3

Author(s):

Tarek Barakat ◽

Joanna Rooke ◽

Dayan Chlala ◽

Renaud Cousin ◽

Jean-François Lamonier ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

High Performance ◽

Active Phase ◽

Catalytic Performance ◽

Reaction Scheme ◽

Oscillatory Behavior ◽

Oh Radicals ◽

Oxidation Reactions ◽

Total Oxidation ◽

Diffuse Reflectance Infrared

In this work, the activity of bimetallic Pd-Au doped hierarchically structured titania catalysts has been investigated in the total oxidation of toluene. In earlier works, doping titania with group Vb metal oxides ensured an increased catalytic performance in the elimination of VOC molecules. A synergy between gold and palladium loaded at the surface of titania supports provided better performances in VOC oxidation reactions. Therefore, the main focus in this work was to investigate the durability of the prepared catalysts under long time-on-stream periods. Vanadium-doped catalysts showed a stable activity throughout the whole 110 h test, whereas, surprisingly, niobium-doped catalysts presented a cycle-like activity while nevertheless maintaining a high performance in toluene elimination. Operando Diffuse Reflectance Infrared Fourrier Transform spectroscopy (DRIFT) experiments revealed that variations in the presence of OH radicals and the presence of carbonaceous compounds adsorbed at the surface of spent catalysts varies with the occurrence of oscillations. X-ray Photoelectron Spectroscopy (XPS) results show that interactions between the material and the active phase provided extra amounts of mobile oxygen species and participated in easing the reduction of palladium. An enhanced redox reaction scheme is thus obtained and allows the occurrence of the cyclic-like performance of the catalyst.

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Novel Carbon Dots Derived from Glycyrrhizae Radix et Rhizoma and Their Anti-Gastric Ulcer Effect

Molecules ◽

10.3390/molecules26061512 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1512

Author(s):

Yuhan Liu ◽

Meiling Zhang ◽

Jinjun Cheng ◽

Yue Zhang ◽

Hui Kong ◽

...

Keyword(s):

Gastric Ulcer ◽

Photoelectron Spectroscopy ◽

Carbon Dots ◽

High Performance ◽

Raw264.7 Cells ◽

Mice Model ◽

X Ray ◽

Glycyrrhizae Radix ◽

Transmission Electron ◽

High Resolution Tem

Glycyrrhizae Radix et Rhizoma (GRR) is one of the commonly used traditional Chinese medicines in clinical practice, which has been applied to treat digestive system diseases for hundreds of years. GRR is preferred for anti-gastric ulcer, however, the main active compounds are still unknown. In this study, GRR was used as precursor to synthesize carbon dots (CDs) by a environment-friendly one-step pyrolysis process. GRR-CDs were characterized by using transmission electron microscopy, high-resolution TEM, fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. In addition, cellular toxicity of GRR-CDs was studied by using CCK-8 in RAW264.7 cells, and the anti-gastric ulcer activity was evaluated and confirmed using mice model of acute alcoholic gastric ulcer. The experiment confirmed that GRR-CDs were the spherical structure with a large number of active groups on the surface and their particle size ranged from 2 to 10 nm. GRR-CDs had no toxicity to RAW264.7 cells at concentration of 19.5 to 5000 μg/mL and could reduce the oxidative damage of gastric mucosa and tissues caused by alcohol, as demonstrated by restoring expression of malondialdehyde, superoxide dismutase and nitric oxide in serum and tissue of mice. The results indicated the explicit anti-ulcer activity of GRR-CDs, which provided a new insights for the research on effective material basis of GRR.

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551. Convalescent plasma early in disease course improves survival in COVID-19

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.745 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S341-S342

Author(s):

Varidhi Nauriyal ◽

Anita Shallal ◽

Amit T Vahia ◽

Linoj Samuel ◽

Robert Tibbetts ◽

...

Keyword(s):

Scale Score ◽

Medical Records ◽

Clinical Status ◽

Ordinal Scale ◽

Optimal Timing ◽

Care Hospital ◽

Future Studies ◽

Patient Gender ◽

Significant Difference ◽

Pcr Test

Abstract Background Convalescent plasma (CP) has been described as a potential therapy for coronavirus disease 2019 (COVID-19). Given paucity of data, we sought to describe characteristics of CP recipients in survivors and non-survivors. Methods We conducted retrospective review of electronic medical records which included any patient with a positive SARS-CoV-2 PCR test who received CP at an 890-bed quaternary care hospital in Southeast Michigan between March-May 2020. Data collected included: demographics, co-morbidities, mSOFA score on admission, laboratory values, and treatment. Outcomes assessed included inflammatory markers and clinical status based on an 8-point ordinal scalea. These values were recorded on admission, the date of CP (day 1), day 3, 7, and day 30 post-CP. Patient outcomes were stratified by ordinal scale score and compared using Mann-Whitney U tests to examine differences in clinical characteristics: scale of 1–4 (“meaningful survivor”), 5–7 (“survivor”), and 8 (“non-survivor”). Results Results of our study are summarized in Table 1 and 2. Non-survivors were older than survivors (62 vs 71 years; p=0.026). There was no statistically significant difference between patient gender, race, number of days from positive PCR test to CP, treatments, and co-morbidities. There was a trend toward higher mSOFA score on admission in non-survivors (p=0.056). A lower ordinal scale score on the date of receiving CP was significantly associated with meaningful survivorship (6 vs 7, p=0.005). Comparisons of Characteristics Based on Ordinal Scale at Day 30 Comparisons of Outcomes Based on Ordinal Scale at Day 30 Conclusion Patients who have a lower ordinal scale score on the date of CP administration are most likely to have meaningful survivorship at day 30. Future studies should evaluate optimal timing and outcomes for CP therapy in COVID-19. Disclosures All Authors: No reported disclosures

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Synthesis of catalysts with fine platinum particles supported by high-surface-area activated carbons and optimization of their catalytic activities for polymer electrolyte fuel cells

RSC Advances ◽

10.1039/d1ra02156g ◽

2021 ◽

Vol 11 (33) ◽

pp. 20601-20611

Author(s):

Md. Mijanur Rahman ◽

Kenta Inaba ◽

Garavdorj Batnyagt ◽

Masato Saikawa ◽

Yoshiki Kato ◽

...

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

High Performance ◽

Activated Carbons ◽

Low Cost ◽

High Surface ◽

High Surface Area ◽

Polymer Electrolyte Fuel Cells ◽

Supported Platinum ◽

Platinum Particles

Herein, we demonstrated that carbon-supported platinum (Pt/C) is a low-cost and high-performance electrocatalyst for polymer electrolyte fuel cells (PEFCs).

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Elucidation of the Crystal Growth Characteristics of SnO2 Nanoaggregates Formed by Sequential Low-Temperature Sol-Gel Reaction and Freeze Drying

Nanomaterials ◽

10.3390/nano11071738 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1738

Author(s):

Saeid Vafaei ◽

Alexander Wolosz ◽

Catlin Ethridge ◽

Udo Schnupf ◽

Nagisa Hattori ◽

...

Keyword(s):

Crystal Growth ◽

Low Temperature ◽

Photoelectron Spectroscopy ◽

High Performance ◽

Freeze Drying ◽

Sno2 Nanoparticles ◽

Sol Gel ◽

Functional Materials ◽

Cost Effective ◽

High Concentration

SnO2 nanoparticles are regarded as attractive, functional materials because of their versatile applications. SnO2 nanoaggregates with single-nanometer-scale lumpy surfaces provide opportunities to enhance hetero-material interfacial areas, leading to the performance improvement of materials and devices. For the first time, we demonstrate that SnO2 nanoaggregates with oxygen vacancies can be produced by a simple, low-temperature sol-gel approach combined with freeze-drying. We characterize the initiation of the low-temperature crystal growth of the obtained SnO2 nanoaggregates using high-resolution transmission electron microscopy (HRTEM). The results indicate that Sn (II) hydroxide precursors are converted into submicrometer-scale nanoaggregates consisting of uniform SnO2 spherical nanocrystals (2~5 nm in size). As the sol-gel reaction time increases, further crystallization is observed through the neighboring particles in a confined part of the aggregates, while the specific surface areas of the SnO2 samples increase concomitantly. In addition, X-ray photoelectron spectroscopy (XPS) measurements suggest that Sn (II) ions exist in the SnO2 samples when the reactions are stopped after a short time or when a relatively high concentration of Sn (II) is involved in the corresponding sol-gel reactions. Understanding this low-temperature growth of 3D SnO2 will provide new avenues for developing and producing high-performance, photofunctional nanomaterials via a cost-effective and scalable method.

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Mechanochemically Synthetized PAN-Based Co-N-Doped Carbon Materials as Electrocatalyst for Oxygen Evolution Reaction

Nanomaterials ◽

10.3390/nano11020290 ◽

2021 ◽

Vol 11 (2) ◽

pp. 290

Author(s):

Paulette Gómez-López ◽

José Ángel Salatti-Dorado ◽

Daily Rodríguez-Padrón ◽

Manuel Cano ◽

Clemente G. Alvarado-Beltrán ◽

...

Keyword(s):

Oxygen Evolution ◽

Photoelectron Spectroscopy ◽

Carbon Nanomaterials ◽

Carbon Materials ◽

Catalytic Performance ◽

X Ray Diffraction ◽

New Class ◽

Electrocatalytic Performance ◽

Alkaline Environments ◽

Metal Doped

We report a new class of polyacrylonitrile (PAN)-based Co-N-doped carbon materials that can act as suitable catalyst for oxygen evolution reactions (OER). Different Co loadings were mechanochemically added into post-consumed PAN fibers. Subsequently, the samples were treated at 300 °C under air (PAN-A) or nitrogen (PAN-N) atmosphere to promote simultaneously the Co3O4 species and PAN cyclization. The resulting electrocatalysts were fully characterized and analyzed by X-ray diffraction (XRD) and photoelectron spectroscopy (XPS), transmission (TEM) and scanning electron (SEM) microscopies, as well as nitrogen porosimetry. The catalytic performance of the Co-N-doped carbon nanomaterials were tested for OER in alkaline environments. Cobalt-doped PAN-A samples showed worse OER electrocatalytic performance than their homologous PAN-N ones. The PAN-N/3% Co catalyst exhibited the lowest OER overpotential (460 mV) among all the Co-N-doped carbon nanocomposites, reaching 10 mA/cm2. This work provides in-depth insights on the electrocatalytic performance of metal-doped carbon nanomaterials for OER.

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High-Performance Resistive Switching in Solution-Derived IGZO:N Memristors by Microwave-Assisted Nitridation

Nanomaterials ◽

10.3390/nano11051081 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1081

Author(s):

Shin-Yi Min ◽

Won-Ju Cho

Keyword(s):

Resistive Switching ◽

Photoelectron Spectroscopy ◽

High Performance ◽

Electric Pulse ◽

Chemical Species ◽

Optical Absorption Coefficient ◽

Microwave Assisted ◽

Synthesis Strategy ◽

Metal Insulator Metal ◽

Switching Characteristics

In this study, we implemented a high-performance two-terminal memristor device with a metal/insulator/metal (MIM) structure using a solution-derived In-Ga-Zn-Oxide (IGZO)-based nanocomposite as a resistive switching (RS) layer. In order to secure stable memristive switching characteristics, IGZO:N nanocomposites were synthesized through the microwave-assisted nitridation of solution-derived IGZO thin films, and the resulting improvement in synaptic characteristics was systematically evaluated. The microwave-assisted nitridation of solution-derived IGZO films was clearly demonstrated by chemical etching, optical absorption coefficient analysis, and X-ray photoelectron spectroscopy. Two types of memristor devices were prepared using an IGZO or an IGZO:N nanocomposite film as an RS layer. As a result, the IGZO:N memristors showed excellent endurance and resistance distribution in the 103 repeated cycling tests, while the IGZO memristors showed poor characteristics. Furthermore, in terms of electrical synaptic operation, the IGZO:N memristors possessed a highly stable nonvolatile multi-level resistance controllability and yielded better electric pulse-induced conductance modulation in 5 × 102 stimulation pulses. These findings demonstrate that the microwave annealing process is an effective synthesis strategy for the incorporation of chemical species into the nanocomposite framework, and that the microwave-assisted nitridation improves the memristive switching characteristics in the oxide-based RS layer.

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Synthesis of Novel Arginine-Based Flame Retardant and Its Application in Lyocell Fabric

Molecules ◽

10.3390/molecules26123588 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3588

Author(s):

Jiayi Chen ◽

Yansong Liu ◽

Jiayue Zhang ◽

Yuanlin Ren ◽

Xiaohui Liu

Keyword(s):

Fourier Transform ◽

Heat Release ◽

Flame Retardant ◽

Photoelectron Spectroscopy ◽

Fourier Transform Infrared ◽

Ftir Analysis ◽

Excellent Thermal Stability ◽

X Ray ◽

Cone Calorimeter Test ◽

Before And After

Lyocell fabrics are widely applied in textiles, however, its high flammability increases the risk of fire. Therefore, to resolve the issue, a novel biomass-based flame retardant with phosphorus and nitrogen elements was designed and synthesized by the reaction of arginine with phosphoric acid and urea. It was then grafted onto the lyocell fabric by a dip-dry-cure technique to prepare durable flame-retardant lyocell fabric (FR-lyocell). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the flame retardant was successfully introduced into the lyocell sample. Thermogravimetric (TG) and Raman analyses confirmed that the modified lyocell fabric featured excellent thermal stability and significantly increased char residue. Vertical combustion results indicated that FR-lyocell before and after washing formed a complete and dense char layer. Thermogravimetric Fourier-transform infrared (TG-FTIR) analysis suggested that incombustible substances (such as H2O and CO2) were produced and played a significant fire retarding role in the gas phase. The cone calorimeter test corroborated that the peak of heat release rate (PHRR) and total heat release (THR) declined by 89.4% and 56.4%, respectively. These results indicated that the flame retardancy of the lyocell fabric was observably ameliorated.

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Metabolomic analysis reveals the interaction of primary and secondary metabolism in white, pale green, and green pak choi (Brassica rapa subsp. chinensis)

Applied Biological Chemistry ◽

10.1186/s13765-020-00574-2 ◽

2021 ◽

Vol 64 (1) ◽

Author(s):

Hyeon Ji Yeo ◽

Seung-A Baek ◽

Ramaraj Sathasivam ◽

Jae Kwang Kim ◽

Sang Un Park

Keyword(s):

Secondary Metabolites ◽

Brassica Rapa ◽

High Performance ◽

Reducing Power ◽

Total Phenolic ◽

Pak Choi ◽

Primary And Secondary Metabolites ◽

Chlorophyll Contents ◽

Significant Difference ◽

Pale Green

AbstractThis study aimed to comprehensively analyze primary and secondary metabolites of three different-colored (white, pale green, and green) pak choi cultivars (Brassica rapa subsp. chinensis) using gas chromatography attached with time-of-flight mass spectrometry (GC-TOFMS) and high-performance liquid chromatography (HPLC). In total, 53 primary metabolites were identified and subjected to partial least-squares discriminant analysis. The result revealed a significant difference in the primary and secondary metabolites between the three pak choi cultivars. In addition, 49 hydrophilic metabolites were detected in different cultivars. Total phenolic and glucosinolate contents were highest in the pale green and green cultivars, respectively, whereas total carotenoid and chlorophyll contents were highest in the white cultivar. Superoxide dismutase activity, 2,2-diphenyl-1-picrylhydraz scavenging, and reducing power were slightly increased in the white, pale green, and green cultivars, respectively. In addition, a negative correlation between pigments and phenylpropanoids was discovered by metabolite correlation analysis. This approach will provide useful information for the development of strategies to enhance the biosynthesis of phenolics, glucosinolates, carotenoids, and chlorophyll, and to improve antioxidant activity in pak choi cultivars. In addition, this study supports the use of HPLC and GC-TOFMS-based metabolite profiling to explore differences in pak choi cultivars.

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