Is water oxidation catalyzed at the surface or within the bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites of pakhomovskyite (Co3(PO4)2⋅8 H2O, Pak) and phosphate-containing Co oxide (CoCat). X-ray spectroscopy reveals that oxidizing potentials transform the crystalline Pak slowly (5-8 h) but completely into the amorphous CoCat. Electrochemical analysis supports high-TOF surface activity in Pak, whereas its amorphization results in dominating volume activity of the thereby formed CoCat material. In the directly electrodeposited CoCat, volume catalysis prevails, but not at very low levels of the amorphous material, implying high-TOF catalysis at surface sites. A complete picture of heterogeneous water oxidation requires insight in catalysis at the electrolyte-exposed "outer surface", within a hydrated, amorphous volume phase, and modes and kinetics of restructuring upon operation.
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http://dx.doi.org/10.1002/anie.201409333 | DOI Listing |
Org Lett
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
An electrochemical strategy for the regioselective construction of seleno-benzothiophenes/furans is reported through electrochemical selenocyclization, followed by Wagner-Meerwein rearrangement. This electro-oxidative tandem process operates under metal-free and external chemical oxidant-free conditions. Advantageously, unprotected homopropargyl alcohols were found to be compatible under the reaction conditions, releasing water and dihydrogen as the biproduct.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemical Engineering, Integrated Engineering Major, College of Engineering, Kyung Hee University, Yongin, 17104, Republic of Korea.
Oxygen evolution reaction (OER) is a half-reaction that occurs at the anode during water electrolysis, and owing to its slow kinetics, it is the rate-limiting step in the process. Alloying with transition metal and combining with transition metal oxide supports are effective methods for modifying the electronic structure of noble metal catalysts and improving their catalytic properties. In this study, we synthesized IrCu/CoO hybrid nanostructures by attaching IrCu alloy nanoparticles onto CoO nanosheets.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Chemistry and Materials Science, Tietotie 3, Espoo, 02150, Finland.
Superhydrophobic surfaces are essential in various industries such as textiles, aviation, electronics and biomedical devices due to their exceptional water-repellent properties. Black silicon (b-Si) would be an ideal candidate for some applications due to its nanoscale topography made with a convenient lithography-free step and complementary metal-oxide-semiconductor (CMOS) compatible fabrication process. However, its use is hindered by serious issues with mechanical robustness.
View Article and Find Full Text PDFInorg Chem
January 2025
Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
In this study, we apply TD-DFT and DFT calculations to explore the mechanistic details of O evolution in an artificial system that closely resembles Photosystem II (PSII). The reaction involves mononuclear Mn(III) complex [Mn(salpd)(OH)] and -benzoquinone under light-driven conditions. Our calculations reveal that the Schiff-base ligand salpd plays a crucial role in several key steps of the reaction, including the light-mediated oxidation of [Mn(salpd)(OH)] to [Mn(salpd)(OH)] by -benzoquinone, the subsequent oxidation of [Mn(salpd)(OH)] to the key Mn(V) intermediate [Mn(salpd)(O)], and the critical O-O bond formation step.
View Article and Find Full Text PDFChem Biodivers
January 2025
Tokat Gaziosmanpasa University Faculty of Arts and Sciences: Tokat Gaziosmanpasa Universitesi Fen Edebiyat Fakultesi, Biology, Tokat, Tokat, TURKEY.
Astragalus tokatensis is a local endemic species and no study exists on this species. In this study, hexane, dichloromethane, methanol and water extracts were obtained from the parts of root, leaf and flower of A. tokatensis.
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