Browsing by Author "Scott, Keith"

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    Nafion-stabilised platinum nanoparticles supported on titanium nitride: An efficient and durable electrocatalyst for phosphoric acid based polymer electrolyte fuel cells
    (Elsevier, 2013) Kumar, Ravi; Pasupathi, Sivakumar; Pollet, Bruno G.; Scott, Keith
    Nafion derived platinum nanoparticles were produced and successfully anchored on titanium nitride (TiN) support (Pt/TiN) and its suitability for phosphoric acid based polymer electrolyte membrane fuel cells is reported. Electrochemical cycling of Nafion stabilised Pt/TiN electrocatalyst exhibits good stability, durability and better electrocatalytic activity than the traditionally employed carbon supported Pt (Pt/C). Platinum supported on TiN exhibits better oxygen reduction reaction (ORR) activity as compared to carbon black (Vulcan XC 72). Nafion stabilised Pt/TiN shows a positive shift of 20 mV in half-wave potential measured from ORR polarisation curve in relation to Pt/C. Nafion stabilised Pt/TiN shows approximately two-fold increase in mass and specific activities than the Pt/C calculated from ORR data at 0.9 V. The improved durability of Pt/TiN catalyst arises from Nafion layer surrounding the Pt nanoparticles and corrosion resistant TiN support. Transition metal nitride based electrocatalysts are more active for cathode due to synergistic effect, which is observed in oxygen reduction reaction.
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    RuxNb1-xO2 catalyst for the oxygen evolution reaction in proton exchange membrane water electrolysers
    (Elsevier, 2013) Puthiyapura, Vinod Kumar; Pasupathi, Sivakumar; Basu, Suddhasatwa; Wu, Xu; Su, Huaneng; Varagunapandiyan, N.; Pollet, Bruno G.; Scott, Keith
    Bimetallic catalyst system of ruthenium oxide (RuO2) and niobium oxide (Nb2O5) was prepared using the Adams method and the hydrolysis method. Physical and electrochemical characterizations of the catalysts were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), cyclic voltammogram (CV) and polarization measurements. Nb2O5 addition to RuO2 was found to increase the stability of RuO2. In Adams method the sodium nitrate was found to be forming complex with Nb2O5 at high temperature reaction. This makes Adams method unsuitable for the synthesis of RuO2eNb2O5 bimetallic system. Hydrolysis method on other hand does not have this problem. But a proper mixture of two oxides was not obtained in hydrolysis method. A lower crystallite size for bimetallic system was obtained with Adams method compared to hydrolysis method. RuO2 prepared by Adams method had higher activity compared to the hydrolysis counterpart in electrolyzer operation with nafion membrane. A cell voltage of 1.62 V was obtained with RuO2 (A) at 1 A/cm2. A higher stability for Ru0.8Nb0.2O2(A) compared to RuO2