scholarly journals Electrochemistry-Induced Restructuring of Tin-Doped Indium Oxide Nanocrystal Films of Relevance to CO2 Reduction

2021 ◽  
Author(s):  
Tawney Knecht ◽  
Shannon W. Boettcher ◽  
James Hutchison
Keyword(s):  
Indium Oxide ◽  
Morphological Evolution ◽  
Co2 Reduction ◽  
Reducing Conditions ◽  
Cathodic Voltage ◽  
Nanocrystal Films ◽  
Primary Focus ◽  
Tin Metal ◽  
Reduction Of Co2

Abstract The electrochemical reduction of CO2 into fuels using renewable electricity presents an opportunity to utilize captured CO2. Electrocatalyst development has been the primary focus of research in this area. This is especially true at the nanoscale, where researchers have focused on understanding nanostructure-property relationships. However, electrocatalyst structure may evolve during operation. Indium- and tin-based oxides have been widely studied as electrocatalysts for CO2 reduction to formate, but evolution of these catalysts during operation is not well-characterized. Here, we report the evolution of nanoscale structure of tin-doped indium oxide nanocrystals under CO2 reduction conditions. We show that sparse monolayer nanocrystal films desorb from the electrode upon charging, but thicker nanocrystal films remain, likely due to increased number of physical contacts. Upon applying a cathodic voltage of -1.0 V vs RHE or greater, the original 10-nm diameter nanocrystals are no longer visible, and instead form a larger microstructural network. Elemental analysis suggests the network is an oxygen-deficient indium-tin metal alloy. We hypothesize that this morphological evolution is the result of nanocrystal sintering due to oxide reduction. These data provide insights into the morphological evolution tin-doped indium oxide nanocrystal electrocatalysts under reducing conditions and highlight the importance of post-electrochemical structural characterization of electrocatalysts.

Functional Characterization of PM6/13, a β3-specific (GPIIIa/CD61) Monoclonal Antibody that Shows Preferential Inhibition of Fibrinogen Binding over Fibronectin Binding to Activated Human Platelets

1998 ◽  
Vol 79 (01) ◽  
pp. 177-185 ◽  
Author(s):  
Ashia Siddiqua ◽  
Michael Wilkinson ◽  
Vijay Kakkar ◽  
Yatin Patel ◽  
Salman Rahman ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Functional Characterization ◽  
Human Platelets ◽  
Western Blots ◽  
Activated Platelets ◽  
Reducing Conditions ◽  
Fibronectin Binding

SummaryWe report the characterization of a monoclonal antibody (MAb) PM6/13 which recognises glycoprotein IIIa (GPIIIa) on platelet membranes and in functional studies inhibits platelet aggregation induced by all agonists examined. In platelet-rich plasma, inhibition of aggregation induced by ADP or low concentrations of collagen was accompanied by inhibition of 5-hydroxytryptamine secretion. EC50 values were 10 and 9 [H9262]g/ml antibody against ADP and collagen induced responses respectively. In washed platelets treated with the cyclooxygenase inhibitor, indomethacin, PM6/13 inhibited platelet aggregation induced by thrombin (0.2 U/ml), collagen (10 [H9262]g/ml) and U46619 (3 [H9262]M) with EC50 = 4, 8 and 4 [H9262]g/ml respectively, without affecting [14C]5-hydroxytryptamine secretion or [3H]arachidonate release in appropriately labelled cells. Studies in Fura 2-labelled platelets revealed that elevation of intracellular calcium by ADP, thrombin or U46619 was unaffected by PM6/13 suggesting that the epitope recognised by the antibody did not influence Ca2+ regulation. In agreement with the results from the platelet aggregation studies, PM6/13 was found to potently inhibit binding of 125I-fibrinogen to ADP activated platelets. Binding of this ligand was also inhibited by two other MAbs tested, namely SZ-21 (also to GPIIIa) and PM6/248 (to the GPIIb-IIIa complex). However when tested against binding of 125I-fibronectin to thrombin stimulated platelets, PM6/13 was ineffective in contrast with SZ-21 and PM6/248, that were both potent inhibitors. This suggested that the epitopes recognised by PM6/13 and SZ-21 on GPIIIa were distinct. Studies employing proteolytic dissection of 125I-labelled GPIIIa by trypsin followed by immunoprecipitation with PM6/13 and analysis by SDS-PAGE, revealed the presence of four fragments at 70, 55, 30 and 28 kDa. PM6/13 did not recognize any protein bands on Western blots performed under reducing conditions. However Western blotting analysis with PM6/13 under non-reducing conditions revealed strong detection of the parent GP IIIa molecule, of trypsin treated samples revealed recognition of an 80 kDa fragment at 1 min, faint recognition of a 60 kDa fragment at 60 min and no recognition of any product at 18 h treatment. Under similar conditions, SZ-21 recognized fragments at 80, 75 and 55 kDa with the 55kDa species persisting even after 18 h trypsin treatment. These studies confirm the epitopes recognised by PM6/13 and SZ-21 to be distinct and that PM6/13 represents a useful tool to differentiate the characteristics of fibrinogen and fibronectin binding to the GPIIb-IIIa complex on activated platelets.

Graphene Supported Tungsten Carbide as Catalyst for Electrochemical Reduction of CO2

2019 ◽  
Author(s):  
Sahithi Ananthaneni ◽  
Rees Rankin
Keyword(s):  
Tungsten Carbide ◽  
Electrochemical Reduction ◽  
Low Cost ◽  
Co2 Reduction ◽  
Platinum Group Metal ◽  
Reduction Reaction ◽  
Metal Carbides ◽  
Depth Study ◽  
Reduction Of Co2 ◽  
Co2 Reduction Reaction

<div>Electrochemical reduction of CO2 to useful chemical and fuels in an energy efficient way is currently an expensive and inefficient process. Recently, low-cost transition metal-carbides (TMCs) are proven to exhibit similar electronic structure similarities to Platinum-Group-Metal (PGM) catalysts and hence can be good substitutes for some important reduction reactions. In this work, we test graphenesupported WC (Tungsten Carbide) nanocluster as an electrocatalyst for the CO2 reduction reaction. Specifically, we perform DFT studies to understand various possible reaction mechanisms and determine the lowest thermodynamic energy landscape of CO2 reduction to various products such as CO, HCOOH, CH3OH, and CH4. This in-depth study of reaction energetics could lead to improvements and develop more efficient electrocatalysts for CO2 reduction.<br></div>

Three-dimensional porous copper-decorated bismuth-based nanofoam for boosting electrochemical reduction of CO2 to formate

2021 ◽  
Author(s):  
Yingchun Zhang ◽  
Changsheng Cao ◽  
Xintao Wu ◽  
Qi-Long Zhu
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Three Dimensional ◽  
Co2 Reduction ◽  
Reduction Reaction ◽  
High Current ◽  
Porous Copper ◽  
Reduction Of Co2 ◽  
Co2 Reduction Reaction ◽  
Wide Potential

Bismuth (Bi)-based nanomaterials are considered as the promising electrocatalysts for electrocatalytic CO2 reduction reaction (CO2RR), but it is challenging to achieve high current density and selectivity in a wide potential...

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

scholarly journals Electrocatalytic CO2 Reduction: From Homogeneous Catalysts to Heterogeneous-Based Reticular Chemistry

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2835 ◽  
Author(s):  
Abdulhadi Al-Omari ◽  
Zain Yamani ◽  
Ha Nguyen
Keyword(s):  
Materials Science ◽  
Co2 Reduction ◽  
Covalent Bond ◽  
Electrochemical Process ◽  
Homogeneous Catalysts ◽  
Catalytic Systems ◽  
Biological Reduction ◽  
Porous Catalyst ◽  
Practical Applications ◽  
Reduction Of Co2

CO2, emitted mainly from fossil fuel combustion, is one of the major greenhouse gases. CO2 could be converted into more valuable chemical feedstocks including CO, HCOOH, HCHO, CH3OH, or CH4. To reduce CO2, catalysts were designed and their unique characteristics were utilized based on types of reaction processes, including catalytic hydrogenation, complex metal hydrides, photocatalysis, biological reduction, and electrochemical reduction. Indeed, the electroreduction method has received much consideration lately due to the simple operation, as well as environmentally friendly procedures that need to be optimized by both of the catalysts and the electrochemical process. In the past few decades, we have witnessed an explosion in development in materials science—especially in regards to the porous crystalline materials based on the strong covalent bond of the organic linkers containing light elements (Covalent organic frameworks, COFs), as well as the hybrid materials that possess organic backbones and inorganic metal-oxo clusters (Metal-organic frameworks, MOFs). Owing to the large surface area and high active site density that belong to these tailorable structures, MOFs and COFs can be applied to many practical applications, such as gas storage and separation, drug release, sensing, and catalysis. Beyond those applications, which have been abundantly studied since the 1990s, CO2 reduction catalyzed by reticular and extended structures of MOFs or COFs has been more recently turned to the next step of state-of-the-art application. In this perspective, we highlight the achievement of homogeneous catalysts used for CO2 electrochemical conversion and contrast it with the advances in new porous catalyst-based reticular chemistry. We then discuss the role of new catalytic systems designed in light of reticular chemistry in the heterogeneous-catalyzed reduction of CO2.

A- and B-site doping effect on physicochemical properties of Sr2−xBaxMMoO6 (M = Mg, Mn, Fe) double perovskites — candidate anode materials for SOFCs

2016 ◽  
Vol 09 (04) ◽  
pp. 1641002 ◽  
Author(s):  
Kun Zheng ◽  
Konrad Świerczek
Keyword(s):  
Physicochemical Properties ◽  
Solid Oxide Fuel Cells ◽  
Anode Materials ◽  
Full Range ◽  
Solid Oxide ◽  
Double Perovskites ◽  
Reducing Conditions ◽  
Redox Stability ◽  
Very High

In this work, we evaluate the physicochemical properties of Sr[Formula: see text]BaxMMoO6 (M [Formula: see text] Mg, Mn, Fe) double perovskites as alternative anode materials for solid oxide fuel cells, for which the effect of substitution of strontium by barium in a full range of compositions is studied. The crystal structure, microstructure, characterization of transport properties (electrical conductivity, Seebeck coefficient) and oxygen content as a function of temperature, as well as chemical stability in oxidizing and reducing conditions are discussed. Fe- and Mo-containing Sr[Formula: see text]BaxFeMoO6 oxides show very high total conductivities with values of 100–1000 S[Formula: see text][Formula: see text]cm[Formula: see text], while Sr[Formula: see text]BaxMgMoO6 present good redox stability.

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