Carbon-based, non-noble metal catalysts for the oxygen reduction reaction (ORR) are crucial for the large-scale application of metal-air batteries and fuel cells. Density functional theory calculations were performed to explore the potential of atomically dispersed MN4/C (M = Fe or Mn) as an ORR catalyst in an acidic electrolyte and the ORR mechanism on MN4/C was systematically studied. The results indicated MN4 as the active site of MN4/C and a four-electron OOH transformation pathway as the preferred ORR mechanism on the MN4/C surface. The Gibbs free energy diagram showed that the rate-determining step of the FeN4/C and MnN4/C catalysts is the formation of the second H2O molecule and OOH*, respectively. FeN4/C exhibited higher thermodynamic limiting potential (0.79 V) and, thus, higher ORR activity than MnN4/C (0.52 V) in an acidic environment; its excellent catalytic performance is due to the nice electron structure and adsorption properties of the FeN4 site. Therefore, this work demonstrates that atomically dispersed MN4/C is a promising catalyst for the ORR.
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http://dx.doi.org/10.1039/d0cp04676k | DOI Listing |
J Phys Chem A
January 2025
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Searching for single-molecule magnets (SMM) with large effective blocking barriers, long relaxation times, and high magnetic blocking temperatures is vitally important not only for the fundamental research of magnetism at the molecular level but also for the realization of new-generation magnetic memory unit. Actinides (An) atoms possess extremely strong spin-orbit coupling (SOC) due to their 5 orbitals, and their ground multiplets are largely split into several sublevels because of the strong interplay between the SOC of An atoms and the crystal field (CF) formed by ligand atoms. Compared to TM-based SMMs, more dispersed energy level widths of An-based SMMs will give a larger total zero field splitting (ZFS) and thus provide a necessary condition to derive a higher .
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom.
ConspectusThe emergence of two-dimensional (2D) materials, such as graphene, transition-metal dichalcogenides (TMDs), and hexagonal boron nitride (h-BN), has sparked significant interest due to their unique physicochemical, optical, electrical, and mechanical properties. Furthermore, their atomically thin nature enables mechanical flexibility, high sensitivity, and simple integration onto flexible substrates, such as paper and plastic.The surface chemistry of a nanomaterial determines many of its properties, such as its chemical and catalytic activity.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Physics, Chung-Ang University, Seoul, 06974, Republic of Korea.
The fundamental characteristics of collective interactions in topological band structures can be revealed by the exploration of charge screening in topological materials. In particular, distinct anisotropic screening behaviors are predicted to occur in Dirac nodal line semimetals (DNLSMs) due to their peculiar anisotropic low-energy dispersion. Despite the recent extensive theoretical research, experimental observations of exotic charge screening in DNLSMs remain elusive, which is partly attributed to the coexisting trivial bands near the Fermi energy.
View Article and Find Full Text PDFAdv Mater
January 2025
Laboratory of Advanced Materials, Institute of Optoelectronics, Fudan University, Shanghai, 200438, P. R. China.
Metal single atoms (SA)-support interactions inherently exhibit significant electrochemical activity, demonstrating potential in energy catalysis. However, leveraging these interactions to modulate electronic properties and extend application fields is a formidable challenge, demanding in-depth understanding and quantitative control of atomic-scale interactions. Herein, in situ, off-axis electron holography technique is utilized to directly visualize the interactions between SAs and the graphene surface.
View Article and Find Full Text PDFJ Biomater Appl
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Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.
his study aimed to evaluate the effects of the atomic layer deposited hydroxyapatite (ALD-HA) coating of the titanium (Ti) surface on human gingival keratinocyte (HGK) cell adhesion, spreading, viability, and hemidesmosome (HD) formation. Grade 2 square-shaped Ti substrates were used ( = 62). Half of the substrates were ALD-HA coated, while the other half were used as non-coated controls (NC).
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