In Situ Confined Synthesis of Ti4 O7 Supported Platinum Electrocatalysts with Enhanced Activity and Stability for the Oxygen Reduction Reaction

Herein an in-situ confined synthesis of highly conductive titanium oxide supported Pt catalysts is successfully synthesized. The method involves crystallization and formation of TiO2 particles inside the inert silica shell introduced via Hexamethyldisilazane (HMDS). The conductivity of titania is found to be greatly enhanced by increased annealing temperature, whereas the inevitable decrease in the specific surface area was effectively inhibited by the confined silica shell derived from HMDS. The optimal catalyst (20Pt 850 FHST), exhibited better ORR activity with a maximum current density of 0.049 mA cm-2 at 0.9 V (vs. NHE) and an onset potential of 0.86 V (vs. NHE). The prolonged cycling test demonstrated superior stability as compared to Pt/C (JM 20). Moreover, X-ray absorption spectroscopy asserts that increased electron population in the Pt 5d-orbital, emanating from the strong metal support interaction, improves the electrochemical performance in ORR. The in-situ HMDS-assisted synthesis can also be extended to other oxide supported catalytic systems.