Tuning Structural Properties of Copper Doped Titania Nanotubes under Different Electrolyte pH

Abstract

The crystalline titania nanotubes (TiNT) were successfully synthesized by electrochemical anodization of titanium foil in electrolyte mixture of ethylene glycol and glycerol in equal volume (1:1) followed by calcination and subsequently copper deposited onto titania nanotubes (Cu/TiNT) via an electrochemical method. The present work explored the influence of different pH (1.60, 5, 7, 9, 10 and pH 12) electrolyte exerted on the structural morphology and photoelectrochemical properties of Cu/TiNT. FESEM micrographs exhibited gigantic spherical-liked and bi-pyramidal-liked Cu particles at low pH whereas nanospherical-liked and nanocubical-liked Cu uniformly deposited on and into TiO2 nanotubes at alkaline pH electrolyte since EDX analysis revealed low Cu detection under alkaline pH electrolyte. The photoelectrochemical test demonstrated that the Cu/TiNT with pH 10 has generated nearly three-fold maximum photocurrent compared to an unmodified TiNT. Apparently, the photogenerated current initially shows an increment pattern until pH 10 and their performance eventually decayed beyond this value. A brief explanation of this phenomenon has been explained in the present study