20.500.12556/DiRROS-23643 Composite based on nickel-functionalized carbon nitride and carbon nanotubes as an efficient electrocatalyst for the oxygen evolution reaction Single metal atom catalysts (SACs) are receiving widespread attention in electrochemical energy conversion reactions due to the rational use of metal resources and maximum atom utilization efficiency. The role of the support in stabilizing the single atoms is crucial for their catalytic stability. Carbon nitride (CN) is an excellent support for SACs but its low electrical conductivity is not appropriate for electrochemical applications. Here, we report an engineered composite material based on multiwall carbon nanotubes (MWCNTs) and single nickel atoms stabilized on CN (Ni–CN) as efficient and robust electrocatalyst for the oxygen evolution reaction (OER). Composites with different mass Ni–CN:MWCNT ratios have been prepared to optimize the contribution of both materials, and characterized by X-ray diffraction, transmission electron microscopy, X-ray absorption, and X-ray photoemission spectroscopy. Results confirmed the self-assembly of both materials and the condensation of the triazine-based structure of CN into heptazine-based onto the MWCNTs’ surface during the synthesis, as well as the presence of single Ni atoms in the composites. The co-presence of NiO nanoparticles was detected for the samples with the highest Ni content. The ratio of NiO nanoparticles to single-atom Ni centers was governed by the Ni–CN:MWCNT ratio employed during synthesis. Electrochemical characterization showed a synergistic effect between Ni–CN and MWCNTs that boosted the OER activity of the composites respect to the individual components. The 1:2 ratio turned out to be the optimal one for the composite preparation, maximizing the combined effects of the catalytic activity of the Ni centers and the electrical conductivity of MWCNTs. The mass activity obtained by this composite was 30 times higher than that of the Ni–CN starting material, attributable to its superior electrical conductivity and improved accessibility of Ni active sites. This study underscores the potential of composite materials to advance SACs toward large-scale application. carbon nanotubes carbon nitride single atom catalysts nickel oxygen evolution reaction materiali kovine katalizatorji ogljik nikelj true false true Angleški jezik Slovenski jezik © 2025 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. Neznano 2025-09-18 12:57:14 2025-09-18 13:14:44 2025-10-24 03:54:44 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 17. 9. 2025; str. 1-10 [article no.] ǂ150581 Vol. 159 Aug. 2025 0000-00-00 Zaloznikova Objavljeno apc 0000-00-00 0000-00-00 2025-08-01 620.1/.2 1879-3487 10.1016/j.ijhydene.2025.150581 249283331 https://www.sciencedirect.com/science/article/pii/S0360319925035803 1 3d8039b0-947e-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=34993 RAZ_Rossetti_Nicolo_2025.pdf RAZ_Rossetti_Nicolo_2025.pdf 1 AE56C07DDC1022A53D31AD63231E563F 68d64f90b342c9093347cbd24ef3cc3569bb350f31b5ffb523694704c5d15635 38fa957e-9480-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=34994 Kemijski inštitut 0 0 0