Elucidating the effect of nitrogen occupancy on the hydrogen evolution reaction for a series of titanium oxynitride electrocatalysts Guangmeimei Yang 1 , Yuxiang Zhou 2,3 , Mengnan Wang 3,4 , James Murawski 3 , Louise I. Oldham 1 , Tian Tian 5 , Ifan E.L. Stephens 3 , Andreas Kafizas 1,2 1 Department of Chemistry, Molecular Science Reseach Hub, Imperial College London, White City, London, W12 0BZ, U.K, 2 London Centre for Nanotechnology, Imperial College London, SW7 2AZ, U.K, 3 Department of Materials, Imperial College London, SW7 2AZ, U.K, 4 Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, U.K, 5 Barrer Centre, Department of Chemical Engineering, Imperial College London, SW7 2AZ, U.K. Titanium nitride (TiN) shows desirable properties for use as an electrocatalyst and catalyst support, as it possesses high electrical conductivity and excellent corrosion resistance 1-3 . However, the effect of oxygen content in the nitride lattice on its ability to drive the hydrogen evolution reaction (HER) is not well understood. Here, a series of titanium oxynitrides (TiN x O 1-x ) with varied nitrogen occupancy (0.53 ≤ x ≤1.0) in the bulk have been fabricated by ammonolysis. Their crystal structures, average crystallite sizes and lattice spacings (and therefore bulk composition) were determined by XRD, their surface compositions were determined by XPS and their surface areas were determined by electrochemical and BET methods. We show that the specific activities of these oxynitrides are strongly correlated with the bulk nitrogen occupancy, despite the similar surface composition derived from XPS analysis. Furthermore, a removal of the oxygen content in the bulk or at the surface was attributed to the upgraded performance (up to 25% increase) seen during extended chronoamperometry (CA) tests. Our results show that minimising bulk oxygen content in this class of material is critical to achieve a more conductive and active material for the HER. References 1. Nitride or Oxynitride? Elucidating the Composition–Activity Relationships in Molybdenum Nitride Electrocatalysts for the Oxygen Reduction Reaction Melissa E. Kreider, Michaela Burke Stevens, Yunzhi Liu, Anjli M. Patel, Michael J. Statt, Brenna M. Gibbons, Alessandro Gallo, Micha Ben-Naim, Apurva Mehta, Ryan C. Davis, Anton V. Ievlev, Jens K. Nørskov, Robert Sinclair, Laurie A. King, and Thomas F. Jaramillo. Chemistry of Materials 2020 32 (7), 2946-2960. 2. Improving the HER Activity and Stability of Pt Nanoparticles by Titanium Oxynitride Support. Milutin Smiljanić, Stefan Panić, Marjan Bele, Francisco Ruiz-Zepeda, Luka Pavko, Lea Gašparič, Anton Kokalj, Miran Gaberšček, and Nejc Hodnik. ACS Catalysis 2022 12 (20), 13021-13033. DOI: 10.1021/acscatal.2c03214. 3. Increasing the Oxygen-Evolution Reaction Performance of Nanotubular Titanium Oxynitride-Supported Ir Nanoparticles by a Strong Metal–Support Interaction. Marjan Bele, Primož Jovanovič, Živa Marinko, Sandra Drev, Vid Simon Šelih, Janez Kovač, Miran Gaberšček, Gorazd Koderman Podboršek, Goran Dražić, Nejc Hodnik, Anton Kokalj, and Luka Suhadolnik. ACS Catalysis 2020 10 (22), 13688-13700. DOI: 10.1021/acscatal.0c03688
P240E
Made with FlippingBook Learn more on our blog