A hollow PdCuMoNiCo high-entropy alloy on carbon hybrid was developed as a high-performance bi-functional electrocatalyst for the oxygen reduction reaction and formic acid oxidation reaction in an acidic medium.
Here, we report a conceptual strategy for introducing spatial sulfur (S)–bridge ligands to regulate the coordination environment of Fe-Co-N dual-metal centers (Spa-S-Fe,Co/NC). Benefiting from the electronic modulation, Spa-S-Fe,Co/NC catalyst showed remarkably enhanced oxygen reduction reaction (ORR) performance with a half-wave potential (
E
1/2
) of 0.846 V and satisfactory long-term durability in acidic electrolyte. Combined experimental and theoretical studies revealed that the excellent acidic ORR activity with a remarkable stability observed for Spa-S-Fe,Co/NC is attributable to the optimal adsorption-desorption of ORR oxygenated intermediates achieved through charge-modulation of Fe-Co-N bimetallic centers by the spatial S-bridge ligands. These findings provide a unique perspective to regulate the local coordination environment of catalysts with dual-metal-centers to optimize their electrocatalytic performance.
The atomic‐local environment of catalytically active sites plays an important role in tuning the activity of carbon‐based metal‐free electrocatalysts (C‐MFECs). However, the rational regulation of the environment is always impeded by synthetic limitations and insufficient understanding of the formation mechanism of the catalytic sites. Herein, the possible cleavage mechanism of carbon nanotubes (CNTs) through the crossing points during ball‐milling is proposed, resulting in abundant CNT tips those are more susceptible to be modified by heteroatoms, achieving precise modulation of the atomic environment at the tips. The obtained CNTs with N, S‐rich tips (N,S‐TCNTs) exhibit a wide potential window of 0.59 V along with H2O2 selectivity for over 90.0%. Even using air as the O2 source, the flow cell system with N,S‐TCNTs catalyst attains high H2O2 productivity up to 30.37 mol gcat.−1 h−1@350 mA cm−2, superior to most reported C‐MFECs. From a practical point of view, a solid electrolyzer based on N,S‐TCNTs is further employed to realize the in‐situ continuous generation of pure H2O2 solution with high productivity (up to 4.35 mmol cm−2 h−1@300 mA cm−2; over 300 h). The CNTs with functionalized tips hold a great permission for practical applications, even beyond H2O2 generation.This article is protected by copyright. All rights reserved
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