Nanostructured Ti –Fe2O3/Cu2O Bilayered Thin Films for Photoelectrochemical Water Splitting

 

Nanostructured Ti-Fe₂O₃/Cu₂O Bilayered Thin Films for Photoelectrochemical Splitting of Water

 

Dipika Sharma, Sumant Upadhyay, Surbhi Choudhary, Vibha R. Satsangi^†,

Rohit Shrivastav and Sahab Dass,

 

Department of Chemistry, ^†Department of Physics & Computer Sciences

 Faculty of Science, Dayalbagh Educational Institute (Deemed University),

Agra-282110 (India)

 

Nanostructured thin films of pure Fe₂O₃, Ti –Fe₂O₃, Cu₂O, and bilayered Fe₂O₃/Cu₂O, Ti-Fe₂O₃/Cu₂O were deposited on ITO glass substrate using spray pyrolysis method.  Among various metal oxide semiconductors, cuprous oxide Cu₂O [Eg=2.4eV] and Iron oxide Fe₂O₃ [Eg=2.1eV] were chosen for the present study on account of being abundant, non-toxic, environmentally safe, having low band gap and possess staggered type band edges which is suitable for efficient charge separation in water splitting process.

All samples were characterized using XRD, SEM and UV–Vis spectrometry. Photo electrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pure Fe₂O₃, Ti –Fe₂O₃, Cu₂O, and Fe₂O₃/Cu₂O, Ti-Fe₂O₃/Cu₂O bilayered thin films shows absorption in visible light region. Nanostructured thin films for all the samples were used as photoelectrode in the Photoelectrochemical cell for water splitting reaction.  Maximum photocurrent density of 2.22 mA/cm² at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe₂O₃/Cu₂O bilayered photoelectrode (Fig.1). Increased photocurrent density and enhanced photoconversion efficiency, exhibited by the bilayered thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe₂O₃/Cu₂O interface. 

Fig. 1 Photocurrent density vs. Applied potential curve for pure Cu₂O(A), Fe₂O₃(B), Ti –Fe₂O₃(C), and Fe₂O₃/Cu₂O(D), Ti-Fe₂O₃/Cu₂O(E) bilayered thin films respectively ,under visible light illumination in 0.1M NaOH electrolytic solution using 150W visible light source of irradiation 150 mW cm^-2 at the position of sample.

 

Keywords: Photoelectrochemical, Water splitting, Bilayered, Cu₂O, Fe₂O₃, Ti- Fe₂O_3, Spray-Pyrolysis