open access publication

Article, 2024

Oxygen Defects Containing TiN Films for the Hydrogen Evolution Reaction: A Robust Thin-Film Electrocatalyst with Outstanding Performance

Nanomaterials, ISSN 2079-4991, Volume 14, 9, Page 770, 10.3390/nano14090770

Contributors

Laghrissi, Ayoub 0000-0003-0368-5669 [1] Es-Souni, Mohammed 0000-0003-4684-2900 (Corresponding author) [2]

Affiliations

  1. [1] University of Southern Denmark
    2. [NORA names: SDU University of Southern Denmark; University; Denmark; Europe, EU; Nordic; OECD];
  2. [2] Fachhochschule Kiel
    3. [NORA names: Germany; Europe, EU; OECD]

Abstract

Density functional theory (DFT) calculations of hydrogen adsorption on titanium nitride had previously shown that hydrogen may adsorb on both titanium and nitrogen sites with a moderate adsorption energy. Further, the diffusion barrier was also found to be low. These findings may qualify TiN, a versatile multifunctional material with electronic conductivity, as an electrode material for the hydrogen evolution reaction (HER). This was the main impetus of this study, which aims to experimentally and theoretically investigate the electrocatalytic properties of TiN layers that were processed on a Ti substrate using reactive ion sputtering. The properties are discussed, focusing on the role of oxygen defects introduced during the sputtering process on the HER. Based on DFT calculations, it is shown that these oxygen defects alter the electronic environment of the Ti atoms, which entails a low hydrogen adsorption energy in the range of -0.1 eV; this leads to HER performances that match those of Pt-NPs in acidic media. When a few nanometer-thick layers of Pd-NPs are sputtered on top of the TiN layer, the performance is drastically reduced. This is interpreted in terms of oxygen defects being scavenged by the Pd-NPs near the surface, which is thought to reduce the hydrogen adsorption sites.

Keywords

Pd-NPs, Pt-NPs, Ti atoms, Ti substrate, TiN films, TiN layer, acidic medium, adsorption, adsorption energy, adsorption sites, atoms, barriers, calculations, conductivity, defects, density, density functional theory, density functional theory calculations, diffusion, diffusion barrier, electrocatalysts, electrocatalytic properties, electrode, electrode materials, electronic conductivity, electronic environment, energy, environment, evolution reaction, films, findings, functional theory, hydrogen, hydrogen adsorption, hydrogen adsorption energy, hydrogen adsorption sites, hydrogen evolution reaction, hydrogen evolution reaction performance, ion sputtering, layer, lowest hydrogen adsorption energy, materials, medium, moderate adsorption energy, multifunctional materials, nanometer-thick layers, nitride, nitrogen, nitrogen sites, outstanding performance, outstandingly, oxygen, oxygen defects, performance, process, properties, range, reaction, reactive ion sputtering, sites, sputtering, sputtering process, study, substrate, surface, theory, thin film electrocatalysts, tin, titanium, titanium nitride

Funders

  • European Commission

Data Provider: Digital Science

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