design of mixed metal sulfide modified tio2-ntas nanocomposite as photoelectrochemical sensor

Abstract: over the past decades, nanoscale tio2 has been widely investigated for photoelectrochemical sensor, photocatalysis and dye-sensitized solar cell applications due to its low cost, nontoxic, photo-stable properties and strong photo-oxidation ability. recently, highly ordered tio2 nanotube arrays (ntas) fabricated by anodization method have attracted much attention for their chemical and mechanical stability, large specific area and good charge-transfer properties [1]. ti-ntas were grown on titanium foils by electrochemical anodization in water-ethylene glycol solution containing ammonium fluoride. the anodization was conducted in the constant 25 v for 2 h, and then the as-prepared ti-ntas electrode was calcinated at 450 ○c for 2h [2]. cu-sn-s alloy was deposited on the tio2-ntas by electrodeposition for 90 s under an applied potential of –1.1 v. the results showed remarkable enhanced uv light photoelectrochemical response of the cu-sn-s modified tio2-ntas in comparison with tio2-ntas in buffer solution. the photoelectrochemical behaviour of rutile (under the uv irradiation) was studied in the present work using the hydrodynamic photoamperometric method. the optimum conditions for rutile determination were studied and citrate buffer solution (ph=5.5) and e=0.0 v (vs. ag/agcl reference electrode) were selected as an optimum supporting electrolyte and applied bias potential. the results showed that in the presence of rutile, the photocurrent response of cu-sn-s modified tio2-ntas electrode was reduced due to the interaction of rutile with cu-sn-s modified tio2-ntas electrode which might impede the electron transfer and accelerate the recombination of photo-induced charge carriers, thus decreasing the photocurrent.