Furthermore, as the electrochemically deposition time increased, the (111), (200) and (220) faces of Pt NPs at2 of 39.87◦, 46.29◦and 67.76◦became more evident, reflecting the face-centered cubic (fcc) structure of nanoparticles. The average crystallite size for Pt NPs was estimated to be around 17 nm byusing the Debye-Scherrer’s equation [22]. This value was smaller than the average pore size of the mesoporous TiO2film determinedby BET measurements.