20.500.12556/RUL-156060 Metal–support interaction between titanium oxynitride and Pt nanoparticles enables efficient low-Pt-loaded high-performance electrodes at relevant oxygen reduction reaction current densities In the present work, we report on a synergistic relationship between platinum nanoparticles and a titanium oxynitride support (TiO$_x$N$_y$/C) in the context of oxygen reduction reaction (ORR) catalysis. As demonstrated herein, this composite configuration results in significantly improved electrocatalytic activity toward the ORR relative to platinum dispersed on carbon support (Pt/C) at high overpotentials. Specifically, the ORR performance was assessed under an elevated mass transport regime using the modified floating electrode configuration, which enabled us to pursue the reaction closer to PEMFC-relevant current densities. A comprehensive investigation attributes the ORR performance increase to a strong interaction between platinum and the TiO$_x$N$_y$/C support. In particular, according to the generated strain maps obtained via scanning transmission electron microscopy (STEM), the Pt-TiO$_x$N$_y$/C analogue exhibits a more localized strain in Pt nanoparticles in comparison to that in the Pt/C sample. The altered Pt structure could explain the measured ORR activity trend via the d-band theory, which lowers the platinum surface coverage with ORR intermediates. In terms of the Pt particle size effect, our observation presents an anomaly as the Pt-TiO$_x$N$_y$/C analogue, despite having almost two times smaller nanoparticles (2.9 nm) compared to the Pt/C benchmark (4.8 nm), manifests higher specific activity. This provides a promising strategy to further lower the Pt loading and increase the ECSA without sacrificing the catalytic activity under fuel cell-relevant potentials. Apart from the ORR, the platinum-TiO$_x$N$_y$/C interaction is of a sufficient magnitude not to follow the typical particle size effect also in the context of other reactions such as CO stripping, hydrogen oxidation reaction, and water discharge. The trend for the latter is ascribed to the lower oxophilicity of Pt-based on electrochemical surface coverage analysis. Namely, a lower surface coverage with oxygenated species is found for the Pt-TiO$_x$N$_y$/C analogue. Further insights were provided by performing a detailed STEM characterization via the identical location mode (IL-STEM) in particular, via 4DSTEM acquisition. This disclosed that Pt particles are partially encapsulated within a thin layer of TiO$_x$N$_y$ origin. oxygen reduction reaction titanium oxynitride support metal−support interaction floating electrode 4DSTEM electrodes metal nanoparticles oxides platinum redox reactions materiali titan reakcija redukcije kisika ORR true false true Angleški jezik Slovenski jezik Članek v reviji 2024-05-06 15:03:39 2024-05-06 15:03:41 2024-05-07 03:44:59 0000-00-00 00:00:00 2024 0 0 Str. 2473–2486 iss. 4 Vol. 14 Feb. 16, 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 620.1/.2 2155-5435 10.1021/acscatal.3c03883 187187459 hrnjic-et-al-2024-metal-support-interaction-between-titanium-oxynitride-and-pt-nanoparticles-enables-efficient-low-pt.pdf hrnjic-et-al-2024-metal-support-interaction-between-titanium-oxynitride-and-pt-nanoparticles-enables-efficient-low-pt.pdf 1 FFCF7DEA91A4FE51A12E2C4BEFF23563 47a9f09e3f4ffae662252a4b4ebb4bec72a35bf912d8362f106dd5eab069f175 4817a115-0ba9-11ef-ab55-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=183277 https://pubs.acs.org/doi/10.1021/acscatal.3c03883 1 112af6d5-0ba9-11ef-ab55-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=183276 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0