Enhanced photoelectrochemical property of gold nanoparticle sensitized TiO2 nanotube: A crucial investigation at electrode–electrolyte interface

• First time electrodeposition of Au nanoparticles on TiO2 nanotube is reported.
• SEM & EDX results confirm Au nanoparticles (GNPs) formed on TiO2 nanotube (T-NT).
• A broad surface plasmon absorption peak due to GNP is confirmed by UV–Vis analysis.
• Charge transfer process from GNP to T-NT is analyzed by EIS and M–S analysis.
• Enhancement of photocurrent of GNP_T-NT over pristine T-NT has been ascribed.

We have reported for the first time a simple one step electrodeposition of gold nanoparticle (GNP) on TiO2 nanotube (TNT) structure and GNP sensitized TNT shows enhanced photoelectrochemical property than pristine TNT in visible region. GNP loaded TNT array photoelectrode has a broad visible light absorption (450–700 nm) observed by UV–Vis spectroscopy. The GNPs are photoexcited due to plasmon resonance and facilitates the photogenerated electron–hole pair separation under visible illumination. Electrochemical impedance spectroscopy measurement ensures efficient electron transfer from nanoparticle to TNT. Charge transfer mechanism at electrode–electrolyte has also been investigated using Mott–Schottky analysis.

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