Morphology Controlled Synthesis of Durable TiO2 Support for Nano-Pt Catalyst for Oxygen Reduction Reaction
In the present work, TiO2 nanorods with specific length and width are synthesized through physical vapor deposition (PVD) technique using the glancing angle deposition (GLAD). Subsequently, the interconnected Pt nanoparticles are deposited on surface of the TiO2 nanorods for efficient catalytic activity and fine electron connectivity towards the electrode substrate. In addition, the controlled porous catalyst matrix would aid the efficient reactant and product transport. Figure 1 shows the scanning electron microscopy images of TiO2 and Pt-TiO2 on silica wafer substrates. These images show the nanorods of TiO2 are encapsulated by ‘bud’ shaped inter connected Pt particles. As the surface energy of Pt is higher than TiO2 surface,4 Pt does not cover the TiO2surface homogeneously resulted structured morphologies. Generally, the electrochemical reactions are surface reactions, the Pt rich edges are possibly involve the ORR reactions and tiny bottom layers are contribute to the electron connectivity.
To study the electrochemical behavior of the synthesized Pt-TiO2, cyclic voltammetry measurements are performed in aq. perchloric acid (0.1 M) on glassy carbon substrates and by using Pt and Ag/AgCl/Cl- as the counter and reference electrodes, respectively. The characteristics peaks of H2 adsorption and desorption (Figure 2) indicate the metallic nature of Pt. The preliminary results that obtained from ORR reveal the enhanced activity and the ultra-high stability of Pt-TiO2catalyst.
The authors gratefully acknowledge financial support from the National Science Foundation (CBET-0748063).
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