Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	NHC–Ni nanoclusters covalently ligated on carbon nanotubes: highly active electrocatalysts for the oxygen evolution reaction
Δημιουργός/Συγγραφέας:	Rapakousiou, Amalia Chalkidis, Savvas G. Minadakis, Michail P. Ruiz-González, María Luisa Navio, Cristina Vougioukalakis, Georgios C. [EL] Ταγματάρχης, Νίκος[EN] Tagmatarchis, Nikos
Ημερομηνία:	2025
Γλώσσα:	Αγγλικά
ISSN:	2050-7488 2050-7496
DOI:	10.1039/D5TA00780A
Περίληψη:	Developing robust and efficient oxygen evolution reaction (OER) electrocatalysts is essential for advancing renewable energy technologies like water electrolysis. Here, we present an electrocatalyst comprising N-heterocyclic carbene (NHC)-ligated nickel nanoclusters (NiNCs) covalently anchored on multi-walled carbon nanotubes (MWCNTs), with only 3.9% Ni/C atomic content. The unique nanoarchitecture, featuring a conductive NHC–Ni(0) core and an electroactive NiOx shell, was prepared via a dual metal-reduction and transmetalation strategy, offering exceptional electrocatalytic stability and efficiency, whereas MWCNTs offer mechanical robustness and a conductive nanocarrier support contributing to the enhanced OER kinetics. The electrocatalyst demonstrates low overpotentials of 320 mV and 500 mV at 10 mA cm−2 and 200 mA cm−2, respectively, in 1 M KOH, with very high specific (jECSA = 133 mA cm−2) and intrinsic (jnNi = 2.8 × 109  mA mol−1 cm2) activities, as well as exceptional turnover frequencies (TOFs), reaching up to 7.4 s−1 under industrially relevant conditions (200 mA cm−2). Electrochemical impedance spectroscopy reveals rapid charge transfer kinetics (Rct: 66 Ω to 9.7 Ω) and efficient interfacial processes, driven by high dispersion and ultrafine NiNC size (<1.6 nm). The synergistic interplay between the NHC–Ni(0) core, which stabilizes the electroactive shell structure, and the MWCNTs, which enhance electron transport and provide mechanical robustness, ensures durability under prolonged cycling, with minimal losses (<1.3% overpotential gain and <0.5% apparent loss of Ni active sites). These results establish MWCNTs-NHC-ligated NiNCs as a scalable and high-performing electrocatalyst, surpassing RuO2 and competitive NiFe-based materials, highlighting how precise nanoengineering through innovative covalent architecture can enable efficient and durable OER technologies in clean energy systems.
Τίτλος πηγής δημοσίευσης:	Journal of Materials Chemistry A
Τόμος/Κεφάλαιο:	13
Τεύχος:	23
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Νανοτεχνολογία[EN] Nanotechnology [EL] Χημική τεχνολογία[EN] Chemical technolgy
Λέξεις-Κλειδιά:	Materials science Electrocatalysis Nickel nanoclusters (NiNCs) Oxygen Evolution Reaction (OER)
Χρηματοδότης:	Hellenic Foundation for Research and Innovation (H.F.R.I.)
Χρηματοδοτικό πρόγραμμα:	NANOElectroCAT
Αναγνωριστικό χρηματοδοτικού προγράμματος:	913
Κάτοχος πνευματικών δικαιωμάτων:	This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://doi.org/10.1039/D5TA00780A
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο