EFFECT OF DEPOSITION TIME ON STRUCTURAL AND CATALYTIC PROPERTIES OF Pt FILMS ELECTRODEPOSITED ON Ti SUBSTRATE

Abstract

Platinum (Pt) films were prepared on Titanium (Ti) surface at various deposition times ranging from 30 to 90 minutes using the electrodeposition technique. The morphology of the Pt films was determined using field emission scanning electron microscope (FESEM). Furthermore, the electrocatalytic activity of the prepared Pt films towards methanol oxidation in alkaline medium was investigated using cyclic voltammetry. The surface morphology changed with different deposition times from less compact durian-like structure at shorter times (< 60 minutes) to more compact durian-like structure at longer times (> 60 minutes). The loading amount and surface coverage of Pt on the Ti surface were increased as the deposition time increased. The calculated values of electrochemically active surface area (ECSA) for the Pt films were increased with increasing deposition time as evident in 30 minutes (6.54 m g), 45 minutes (7.34 m g) and 60 minutes (8.08 m g). Nevertheless, the ECSA value dropped to 7.70 m g for longer deposition time (90 minutes). This may be caused by the coagulation of the Pt centres with the growth of neighbouring centres, which decreasing the available active surface area on the films. This film also demonstrated the highest stability for methanol oxidation reaction (MOR) in alkaline medium with the result of 5.18 mA cm at 1 hour.