Electrocatalytic reduction reactions (i.e., the hydrogen evolution reaction (HER) and oxygen reduction reaction) at individual, faceted Au nanocubes (NCs) and nano-octahedra (ODs) expressing predominantly {100} and {111} crystal planes on the surface, respectively, were studied by nanoscale voltammetric mapping. Cyclic voltammograms were collected at individual nanoparticles (NPs) with scanning electrochemical cell microscopy (SECCM) and correlated with particle morphology imaged by electron microscopy. Nanoscale measurements from a statistically informative set of individual NPs revealed that Au NCs have superior HER electrocatalytic activity compared to that of Au ODs, in good agreement with macroscale cyclic voltammetry measurements. Au NCs exhibited more particle-to-particle variation in catalytic activity compared to that with Au ODs. The approach of single-particle SECCM imaging coupled with macroscale CV on well-defined NPs provides a powerful toolset for the design and activity assessment of nanoscale electrocatalysts.
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http://dx.doi.org/10.1021/acs.nanolett.9b04640 | DOI Listing |
Adv Sci (Weinh)
January 2025
The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, M5S 3G4, Canada.
Ammonia (NH) is esteemed for its attributes as a carbon-neutral fuel and hydrogen storage material, due to its high energy density, abundant hydrogen content, and notably higher liquefaction temperature in comparison to hydrogen gas. The primary method for the synthetic generation of NH is the Haber-Bosch process, involving rigorous conditions and resulting in significant global energy consumption and carbon dioxide emissions. To tackle energy and environmental challenges, the exploration of innovative green and sustainable technologies for NH synthesis is imperative.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
Electrochemical water splitting is a promising approach to convert renewable energy into hydrogen energy and is beneficial for alleviating environmental pollution and energy crises, and is considered a clean method to achieve dual-carbon goals. Electrocatalysts can effectively reduce the reaction energy barrier and improve reaction efficiency. However, designing electrocatalysts with high activity and stability still faces significant challenges, which are closely related to the structure and electronic configuration of catalysts.
View Article and Find Full Text PDFACS Appl Energy Mater
January 2025
School of Materials Science & Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Electrolysis of impure water (such as seawater) has recently garnered research interest as it may enable hydrogen production at reduced costs. However, the tendency of impurity ions and other species to degrade electrocatalysts and membranes within an electrolyzer is a serious challenge. Here, we investigate the effects of copper impurities of varying concentrations on the hydrogen evolution reaction (HER) using platinum electrocatalysts.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Key Laboratory of Precision and Intelligent Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
Induced by a sharp-tip-enhanced electric field, periodical nanoassemblies can regulate the reactant flux on the electrode surface, efficiently optimizing the mass transfer kinetics in electrocatalysis. However, when the nanoscale building blocks in homoassemblies are arranged densely, it results in the overlap and reduction of the local electric field. Herein, we present a comprehensive kinetic heteromodel that simultaneously couples the sharp-tip-enhanced electric field and charge transfer electric field between different building blocks with any arrangement densities.
View Article and Find Full Text PDFFood Chem
January 2025
College of Food Science and Engineering, Shandong Agricultural University, Taian 271018, People's Republic of China. Electronic address:
Herein, we synthesized a novel injectable porous magnetic hydrogel (MHG) at room temperature using carboxymethyl chitosan (CMCS), polydopamine (PDA), sodium alginate (SA), polyethyleneimine (PEI) and copper ferrite (CuFeO) as building blocks. The CMCS and SA as monomers provided good film-forming and anti-fouling properties for MHG. The PDA-coated CuFeO as a cross-linking agent improved the homogeneity, adsorption and electrocatalytic performance of MHG, but also generated a macroporous hydrogel structure which was beneficial for sensing applications.
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