Pt is an excellent and widely used hydrogen evolution reaction (HER) catalyst. However, it is a rare and expensive metal, and alternative catalysts are being sought to facilitate the hydrogen economy. As tungsten carbide (WC) has a Pt-like occupied density of states, it is expected to exhibit catalytic activity. However, unlike Pt, excellent catalytic activity has not yet been observed for mono WC. One of the intrinsic differences between WC and Pt is in their magnetic properties; WC is non-magnetic, whereas Pt exhibits high magnetic susceptibility. In this study, the WC lattice was doped with ferromagnetic Co nanocrystals to introduce an ordered-spin atomic configuration. The catalytic activity of the Co-doped WC was ∼30% higher than that of Pt nanoparticles for the HER during the hydrolysis of ammonia borane (NHBH), which is currently attracting attention as a hydrogen fuel source. Measurements of the magnetisation, enthalpy of adsorption, and activation energy indicated that the synergistic effect of the WC matrix promoting hydrolytic cleavage of NHBH and the ferromagnetic Co crystals interacting with the nucleus spin of the protons was responsible for the enhanced catalytic activity. This study presents a new catalyst design strategy based on the concept of an internal magnetic field. The WC-Co material presented here is expected to have a wide range of applications as an HER catalyst.
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http://dx.doi.org/10.1039/d1ra01181b | DOI Listing |
Nat Prod Res
January 2025
Laboratory of Natural Products and Heterocyclic Synthesis, Department of Organic Chemistry, Faculty of Sciences, The University of Yaoundé 1, Yaoundé, Cameroon.
From the leaves of , fourteen compounds were isolated and identified: D-mannitol (), a mixture of β-sitosterol () and stigmasterol (), α-amyrin (), betulin (), lupeol (), lupenone (), betulinic acid (), taraxerol (), 3β-(E)-coumaroyltaraxerol (), 3β-(Z)-coumaroyltaraxerol (), ursolic acid (), stigmasterol 3-O-β-D-glucoside (), and β-sitosterol 3-O-β-D-glucoside (). These compounds were analysed through NMR spectroscopy (both 1D and 2D) and by comparing them to previously published data. Compounds , , , and - have been identified from this species for the first time.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Graduate School of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan.
Selective modification of chemically active sites on supports, such as steps, edges, and corners, with metal nanoparticles (NPs) is a challenging topic in the fields of catalysis and photocatalysis. However, the formation of site-selective, high-density metal NPs on a support has not yet been achieved. Radial ZnO mesocrystals composed of hexagonal nanowires (NWs) with {101̅0} sidewalls were synthesized by a simple solution-phase method.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
Steviol glycosides (SGs) are highly valued for their sweetness, safety, and zero calories, but their bitter taste and low solubility limit their application. Modifying glycosyl units is a promising strategy to improve sensory qualities. In this study, we identified the enzyme UGT94E13 through phylogenetic analysis and enzyme screening, which catalyzes the glycosylation of rebaudioside M2 (Reb M2) at the C-13 position, producing the novel β-1,6--glycosylated product rebaudioside M9 (Reb M9).
View Article and Find Full Text PDFJ Bacteriol
January 2025
Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Microbiology and Biotechnology, University of Tübingen, Tübingen, Baden-Württemberg, Germany.
Unlabelled: is well adapted to survive and persist in the infected host, escaping the host's immune response. Since polyamines such as spermine, which are synthesized by infected macrophages, are able to inhibit the growth of , the pathogen needs strategies to cope with these toxic metabolites. The actinomycete , a close relative of makes use of a gamma-glutamylation pathway to functionally neutralize spermine.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China.
An OER catalyst showing both high activity and stability in promoting oxygen evolution is important for its practical application in electrochemical water-splitting. Here, we report the screening of such a catalyst by optimizing the Ni(II)-doping in Co(III)-based layered double hydroxides (LDHs). Such LDH samples tailored with Ni(II)-doping are prepared by an oxidative intercalation reaction where brucite-like Ni(II)Co(II)(OH) (0 ≤ ≤ 0.
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