Improvement of photoelectrochemical performance of high-stable Mo-BiVO۴thin film by optimization of preparation condition

BiVO۴ is considered an excellent semiconductor [۱], widely used in photocatalysis, photodegradation and water oxidation [۲]. However, the photoelectrochemical (PEC) activity of pure BiVO۴ thin film is fairly low due to its poor charge transport condition and poor adhesion to the substrate [۳,۴]. Herein, Mo doping approach was employed to enhance charge transportconductivity and a modified spin coating technique was utilized to increase the adhesion anduniformity of Mo-BiVO۴ thin films. This layer was synthesized from the combination ofammonium metavanadate, sodium molybdate and bismuth nitrate in ethylene glycol solvent, then it was coated via a modified spin coating method on the substrate in the form of a thin layer and it was calcined by placing in an oven at a temperature of ۴۰۰οC for ۱ h. The obtained Mo-BiVO۴ thin film exhibited a mesoporous surface which was coated uniformly on the whole of the ITO substrate surface with excellent adhesion. Mo-BiVO۴/ITO layer was used as a photoanode in a PEC cell.Different electrolytes namely Na۲SO۴, Na۲SO۳, NaOH and NaNO۳, were investigated to get the best PEC performance. The obtained photo-current of Mo-BiVO۴ photoanode in the Na۲SO۳solution was higher than the other mentioned electrolytes. After that, the concentration of the Na۲SO۳ electrolyte was evaluated in the range of ۰.۰۱ to ۰.۱M. The highest current was obtained for the electrolyte with concentration of ۰.۰.۰۷M. using such optimal conditions, the photocurrent of Mo-BiVO۴ photoanode was ۴-fold higher than primary conditions with high stability.

کلیدواژه ها:

Photoelectrochemical ، Mo-BiVO۴ thin film ، High-stable electrode ، spin coating method