Rational design of metal oxide supported non-precious metals is essential for the development of stable and high-efficiency oxygen reduction reaction (ORR) electrocatalysts. Here, an efficient ORR catalyst consisting of binary Fe/Co nanoclusters supported by defective tungsten oxide and embedded N-doped carbon layer (NC) with a 3D ordered macroporous architecture (3DOM Fe/Co@NC-WO ) is developed. The oxygen deficient 3DOM WO not only serves as a porous and stable support, but also enhances the conductivity and ensures good dispersion of the binary Fe/Co nanocluster, benefiting its ORR catalytic activity. Theoretical calculation shows that there exists a synergistic effect of electron transfer from Fe to Co in the supported binary Fe/Co cluster, promoting the ORR reaction energetics. Accordingly, the 3DOM Fe/Co@NC-WO catalyst exhibits excellent ORR activity in alkaline medium with a half wave potential (E ) of 0.87 V higher than that of Pt/C (0.85 V). The zinc-air batteries assembled by 3DOM Fe/Co@NC-WO cathode deliver a higher power density and specific capacity than that of Pt/C. A new strategy of combining synergistic binary-metal nanoclusters and conductive metal oxide support design is provided here to develop efficient and durable ORR electrocatalyst.
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http://dx.doi.org/10.1002/advs.202104237 | DOI Listing |
J Chem Phys
October 2024
Frontier of Extreme Physics, Space Metrology Group, Korea Research Institute of Standards and Science, 209 Gajeong-Ro, Yuseong-Gu, Daejeon 34113, Republic of Korea.
In this study, we investigate the excess volume (VE) of 24 binary miscible and compound alloy melts using electrostatic levitation. Notably, Pd50X50 (X = Fe, Co, and Ni) and Pt50Fe50 solid solutions with slightly negative or zero mixing enthalpy (ΔHmix) display pronounced positive VE and significantly improved liquid stability after alloying, whereas compound alloy liquids with negative ΔHmix exhibit negative VE. Moreover, the VE of Pd50X50 and Pt50X50 consistently decreases with the increasing number of electrons in X, indicating a magneto-volume effect observed in specific heat measurements.
View Article and Find Full Text PDFSmall
September 2024
Hydrogen Research Department, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea.
Anion exchange membrane water electrolysis (AEMWE) offers a sustainable path for hydrogen production with advantages such as high current density, dynamic responsiveness, and low-cost electrocatalysts. However, the development of efficient and durable oxygen evolution reaction (OER) electrocatalysts under operating conditions is crucial for achieving the AEMWE. This study systematically investigated Fe-Co-Ni ternary amorphous electrocatalysts for the OER in AEMWE through a comprehensive material library system comprising 21 composition series.
View Article and Find Full Text PDFJ Mater Chem A Mater
August 2024
Institute of Applied Physics, Vienna University of Technology 1040 Vienna Austria
Multi-element alloys and high-entropy alloys show promising electrocatalytic behavior for water splitting and other catalytic reactions, due to their highly tunable composition. While preparation and synthesis of these materials are thoroughly investigated, the true reactive surface composition is still not well understood, as it may significantly differ from the bulk composition. Precise knowledge and understanding of resulting surface composition is crucial for effective control of the electrocatalytic performance.
View Article and Find Full Text PDFThe synthesis and characterization of spinel cobalt-based metal oxides (MCoO) with varying 3d-transition metal ions (Ni, Fe, Cu, and Zn) were explored using a hydrothermal process (140 °C for two hours) to be used as alternative counter electrodes for Pt-free dye-sensitized solar cells (DSSCs). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed distinct morphologies for each metal oxide, such as NiCoO nanosheets, Cu CoO nanoleaves, Fe CoO diamond-like, and Zn CoO hexagonal-like structures. The X-ray diffraction analysis confirmed the cubic spinel structure for the prepared MCoO films.
View Article and Find Full Text PDFChemphyschem
September 2024
School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Chemical Theory and Mechanism, Chongqing University, Chongqing, 401331, China.
Two-dimensional MXenes have recently garnered significant attention as electrocatalytic materials for hydrogen evolution reaction (HER). However, previous theoretical studies mainly focused on the effect of pure functional groups while neglecting hybrid functional groups that are commonly observed in experiments. Herein, we investigated the hybrid functionalized MoCT MXene (T=-O, -F or -OH) to probe the HER properties.
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