Because high-index facets (HIFs) possess high surface energy, the metal nanoparticles enclosed with HIFs are eliminated during their growth in a conventional shape-controlled synthesis due to the thermodynamics that drives the particles minimizing their total surface energy. This study develops a double-step potential method to prepare an unprecedentedly stellated Au nanocrystals (NCs) bounded by high-index {711} and {331} facets in deep eutectic solvent (DES) medium. The formation of Au NCs bounded by HIFs was systematically studied. It has demonstrated that the shapes of Au NCs are strongly dependent on the size of seeds and the growth potentials as well as the urea adsorbates in the DES. By adjusting the size of seeds and the growth potentials, the stellated Au NCs can be transformed into concave hexoctahedra (HOH) with high-index {421} facets and concave trisoctahedra (TOH) with high-index {991} facets. The electrocatalytic activities of the as-prepared Au NCs are evaluated by glucose oxidation. Thanks to HIFs having high density of atomic steps and kinks, the stellated, TOH, and HOH Au NCs exhibit higher electrocatalytic activity than that of the polycrystalline Au electrode, demonstrating that the steps and kinks serve as the active sites and play an important role in glucose electro-oxidation.
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http://dx.doi.org/10.1021/acs.langmuir.7b00964 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Key Laboratory of Near-Net Forming of Light Metals of Liaoning Province, Dalian Jiaotong University, Dalian 116028, China.
Porous CuNi films are promising candidates for electrocatalytic water splitting, with their catalytic performance largely influenced by the crystallographic structure and chemical state. In this study, by employing a magnetic field-controlled bubble template-assisted electrodeposition method, CuNi films with a preferred Ni(111) crystal orientation were synthesized. Moreover, adjusting the magnetic field direction during deposition can affect the degree of preferred orientation and, consequently, the electrochemical activity of the films.
View Article and Find Full Text PDFChemphyschem
December 2024
Jilin University, Jilin University, Renmin Street, 130022, ChangChun, CHINA.
Electrochemical reduction of nitrate to ammonia (NO3RR) offers a promising strategy for renewable ammonia (NH3) synthesis and wastewater treatment, but still suffers from limited activity and NH3 selectivity due to the lack of effective electrocatalyst. Here, we perform a four-steps screening strategy to screen high performance NO3RR catalyst by density functional theory calculations using 23 single transition metals atom doped on 1T-WS2/graphene (TM@1T-WS2/graphene) as candidates. The results show that Cu@1T-WS2/graphene exhibits the highest NO3RR activity among 23 candidates with a low rate determining step energy barrier of 0.
View Article and Find Full Text PDFChemSusChem
December 2024
Sungkyunkwan University, Department of Physics, 2066, Seobu-ro,, Jangan-gu,, 16419, Suwon, KOREA, REPUBLIC OF.
The oxygen evolution reaction (OER) is a critical challenge in electrocatalytic water splitting, hindered by high energy demands and slow kinetics. Polyoxometalates (POMs), recognized for their unique redox capabilities, structural archetypes, and molecular precision, are promising candidates for the oxygen evolution reaction (OER). Yet, their application is hindered by high water solubility, causing rapid degradation and efficiency loss under harsh OER conditions.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China; Key Laboratory of Low Carbon Energy and Chemical Engineering of Gansu Province, Lanzhou 730050, PR China.
Heteroatom-doped carbon materials are widely used to improve the electrocatalytic oxidation of methanol; however, the underlying mechanisms driving this enhancement remain poorly understood. A major challenge lies in developing non-doped carbon supports with tunable intrinsic defect types tailored for metal-based catalysts. In this study, we synthesize a series of ordered mesoporous carbon (OMC) supports with adjustable edge defect densities by varying roasting temperatures and employing a zinc (Zn) evaporation strategy to systematically investigate the impact of edge defects on methanol oxidation reaction (MOR) performance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
University of Wisconsin-Madison, Chemical and Biological Engineering, 1415 Engineering Drive, 53706, Madison, UNITED STATES OF AMERICA.
In this study, we employed EC-MS to elucidate the role of halide anions in electrochemical CO2 and CO reduction. We found that the undesired hydrogen evolution reaction (HER) was significantly suppressed by the anion used. Specifically, the rates of H2 production decreased in the order KF > KCl > KI, meaning that I- most strongly suppressed HER.
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