In the present work, the oxygen reduction reaction (ORR) is explored in an acidic medium with two different catalytic supports (multi-walled carbon nanotubes (MWCNTs) and nitrogen-doped multi-walled carbon nanotubes (NMWCNTs)) and two different catalysts (copper phthalocyanine (CuPc) and sulfonic acid functionalized CuPc (CuPc-SO )). The composite, NMWCNTs-CuPc-SO exhibits high ORR activity (assessed based on the onset potential (0.57 V vs. reversible hydrogen electrode) and Tafel slope) in comparison to the other composites. Rotating ring disc electrode (RRDE) studies demonstrate a highly selective four-electron ORR (less than 2.5 % H O formation) at the NMWCNTs-CuPc-SO . The synergistic effect of the catalyst support (NMWCNTs) and sulfonic acid functionalization of the catalyst (in CuPc-SO ) increase the efficiency and selectivity of the ORR at the NMWCNTs-CuPc-SO . The catalyst activity of NMWCNTs-CuPc-SO has been compared with many reported materials and found to be better than several catalysts. NMWCNTs-CuPc-SO shows high tolerance for methanol and very small deviation in the onset potential (10 mV) between the linear sweep voltammetry responses recorded before and after 3000 cyclic voltammetry cycles, demonstrating exceptional durability. The high durability is attributed to the stabilization of CuPc-SO by the additional coordination with nitrogen (Cu-N ) present on the surface of NMWCNTs.
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http://dx.doi.org/10.1002/cphc.202300117 | DOI Listing |
J Phys Chem Lett
January 2025
Hefei National Research Center for Physical Sciences at the Microscale, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China.
Heterogenous single-atom catalysts (SACs) are reminiscent of homogeneous catalysts because of the similarity of structural motif of active sites, showing the potential of using the advantage of homogeneous catalysts to tackle challenges in hetereogenous catalysis. In heterogeneous oxygen electrocatalysis, the homogeneity of adsorption patterns of reaction intermediates leads to scaling relationships that limit their activities. In contrast, homogeneous catalysts can circumvent such limits by selectively altering the adsorption of intermediates through secondary coordination effects (SCEs).
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Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
Cardiogenic shock (CS) is associated with significant mortality. Advances in pharmacological therapies and mechanical circulatory support (MCS) devices have markedly improved the therapeutic approach to CS, though treatment efficacy and safety vary. The recent DanGer shock trial showed a significant reduction in 6-month mortality for CS patients due to acute myocardial infarction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Central South University, chemistry, CHINA.
The two-dimensional lamellar materials disperse platinum sites and minimize noble-metal usage for fuel cells, while mass transport resistance at the stacked layers spurs device failure with a significant performance decline in membrane electrode assembly (MEA). Herein, we implant porous and rigid sulfonated covalent organic frameworks (COF) into the graphene-based catalytic layer for the construction of steric mass-charge channels, which highly facilitates the activity of oxygen reduction reactions in both the rotating disk electrode (RDE) measurements and MEA device tests. Specifically, the normalized mass activity is remarkably boosted by 3.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Applied Chemistry, Waseda University, 513 Wasedatsurumakicho, Shinjuku, Tokyo 162-0041, Japan.
Nitroarenes are highly versatile building blocks in organic synthesis, playing a pivotal role in various reactions. Common transformations involving nitroarenes include nucleophilic aromatic substitution (SAr) reactions, where the nitro group functions both as a potent electron-withdrawing group that activates the aromatic ring and as a leaving group facilitating the substitution. Additionally, the direct transformation of nitro groups, such as reduction-driven syntheses of amines and carboxylic acids, as well as -substitution SAr reactions, have been extensively explored.
View Article and Find Full Text PDFHeliyon
January 2025
Research Center for Emergency and Disaster Resilience, Red Crescent Society of the Islamic Republic of Iran, Tehran, Iran.
Considerable research has focused on advanced wound dressing technology over the past decade. The increasing emphasis on health and medical treatment is crucial to the modern healthcare system. Consequently, high-quality wound dressings with advanced standards are essential for superior medical care.
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