Morphology of electrodeposited WO3 studied by atomic force microscopy

Electrochromic WO3 was prepared on highly oriented pyrolytic graphite (HOPG) by electrodeposition under constant current in an alcohol-containing solution. The morphology and the early stage growth mechanism of electrodeposited WO3 were studied by tapping mode atomic force microscopy (TMAFM). The series of AFM images showed how the morphology of WO3 formed on HOPG was affected by the electrodeposition parameters. WO3 electrodeposited on HOPG has a porous structure and exhibits a self-leveling process. The effects of current density, current efficiency, and hydrogen evolution on the morphology were discussed.