The use of sonication to dissolve or disperse solids in solvents is a common practice in catalytic studies. However, the frequency and power of commercial ultrasonic baths are within the right range to trigger unwanted sonochemical reactions that can be a source of interference. Based on our own experience, we have noted that sonication used to disperse heterogeneous photocatalysts in water-alcohol mixtures as the first step in light-driven hydrogen evolution can lead to hydrogen evolution, which is not related to any photochemical or photocatalytic process. Furthermore, "dark" hydrogen evolution continues even when sonication is stopped, which can cause significant problems for time-dependent studies. To the best of our knowledge, this phenomenon has not been described as a potential issue for light-driven hydrogen evolution studies, and it should, therefore, be brought to the attention of the energy conversion research community to avoid errors in ongoing and future hydrogen evolution studies.
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http://dx.doi.org/10.1021/acsomega.0c03110 | DOI Listing |
Nanoscale Horiz
January 2025
Department of Chemical Engineering, Hampton University, Hampton, VA 23668, USA.
In this work, we use experimental and theoretical techniques to study the origin of the boosted hydrogen evolution reaction (HER) catalytic activity of two pyridyl-pyrrolidine functionalized C fullerenes. Notably, the mono-(pyridyl-pyrrolidine) penta-adduct of C has exhibited a remarkable HER catalytic activity as a metal-free catalyst, delivering an overpotential () of 75 mV RHE and a very low onset potential of -45 mV RHE. This work addresses fundamental questions about how functionalization on C changes the electron density on fullerene cages for high-performance HER electrocatalysis.
View Article and Find Full Text PDFChemistry
January 2025
National & Kapodistrian University of Athens, Chemistry, Panepistimiopolis, Zografou, 15771, Athens, GREECE.
The prominence of binuclear catalysts underlines the need for the design and development of diverse bifunctional ligand frameworks that exhibit tunable electronic and structural properties. Such strategies enable metal-metal and ligand-metal cooperation towards catalytic applications, improve catalytic activity, and are essential for advancing multi-electron transfers for catalytic application. Hereby, we present the synthesis, crystal structure, and photocatalytic properties of a binuclear Ni(II) complex, [Ni2(1,10-phenanthroline)2(2-sulfidophenolate)2] (1), which crystallizes in the centrosymmetric triclinic system (P-1) showing extensive intra- and inter- non-coordinated interactions.
View Article and Find Full Text PDFChem Sci
January 2025
School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Chemical Theory and Mechanism, Chongqing University Chongqing 401331 China
Atomically precise gold nanoclusters have shown great promise as model electrocatalysts in pivotal electrocatalytic processes such as the hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CORR). Although the influence of ligands on the electronic properties of these nanoclusters is well acknowledged, the ligand effects on their electrocatalytic performances have been rarely explored. Herein, using [Au(SR)] nanoclusters as a prototype model, we demonstrated the importance of ligand hydrophilicity hydrophobicity in modulating the interface dynamics and electrocatalytic performance.
View Article and Find Full Text PDFACS Phys Chem Au
January 2025
University of Duisburg-Essen, Faculty of Chemistry, Theoretical Catalysis and Electrochemistry, Universitätsstraße 5, Essen 45141, Germany.
The direct conversion of dinitrogen to nitrate is a dream reaction to combine the Haber-Bosch and Ostwald processes as well as steam reforming using electrochemistry in a single process. Regrettably, the corresponding nitrogen oxidation (NOR) reaction is hampered by a selectivity problem, since the oxygen evolution reaction (OER) is both thermodynamically and kinetically favored in the same potential range. This opens the search for the identification of active and selective NOR catalysts to enable nitrate production under anodic reaction conditions.
View Article and Find Full Text PDFThe James Webb Space Telescope has discovered a surprising population of bright galaxies in the very early Universe (≲500 Myr after the Big Bang) that is hard to explain with conventional galaxy-formation models and whose physical properties are not fully understood. Insight into their internal physics is best captured through nebular lines, but at these early epochs, the brightest of these spectral features are redshifted into the mid-infrared and remain elusive. Using the mid-infrared instrument onboard the James Webb Space Telescope, here we present a detection of Hα and doubly ionized oxygen ([O iii] 4959,5007 Å) from the bright, ultra-high-redshift galaxy candidate GHZ2/GLASS-z12.
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