Tungsten Oxide Nanoplate Film as a Highly Active Solar-Driven Photocatalyst
Chin Wei Lai.
A WO3 nanoplate-like film with an average edge width of approximately 20 nm and thickness
of approximately 250 nm was fabricated via electrochemical anodization of W film at 60 V in a
bath with electrolytes composed of ethylene glycol and 0.7 wt% NH4F. The influence of applied potential
on the morphology of the anodic oxide was investigated. The growth of the nanoplate-like
morphology might be attributed to the competition between electrochemical oxide formation and
chemical etching by the corrosive [WFn](n-6) complex ions at minimal applied potential of 60 V. In
addition, the presence of tungstite (WO3H2O) with an orthorhombic structure was observed within the
WO3 nanoplate-like film, which has a layered structure with sheets of distorted W–O octahedral units sharing corners. All
of the anodic WO3 nanostructured films were annealed and their electrochemical ability was investigated under solarillumination.
A maximum photocurrent density of 1.50 mA/cm2 was observed for the WO3 nanoplate-like film because
more incident photons could be harvested to generate photo-induced charge carriers under solar-illumination.
Keywords: Electrochemical anodization, photoelectrochemical, solar-illumination, WO3 nanoplate.
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