Effect of Electrolytes on the BiOI/SnO₂ Heterostructure to Achieve Stable Photo-Induced Carrier Generation

Abstract

Heterostructures have recently been used to generate stable photo-induced currents via photoelectrochemical (PEC) activity. However, the effect of electrolytes on charge-transfer kinetics and the generation of photo-induced currents on heterostructures are major challenges in PEC. The effect of the electrolyte on the synthesized photoelectrodes is demonstrated in this study under various conditions using electrochemical impedance spectroscopy, linear sweep voltammetry, chronoamperometry, and Tafel analyses. The lowest transfer kinetics resistance and highest photocurrent densities are achieved in 0.1 M KOH when compared to those in 0.1 M Na2SO4 aqueous electrolytes. Furthermore, various applied voltage effects on the generation of currents have been studied for the synthesized electrodes at a voltage of +0.5 V in both electrolytes. The maximum induced-current achieved was 1.39 mA cm−2 for BW-SO, under illumination in the 0.1 M KOH electrolyte. The BW-SO heterostructure presented enhanced performance due to improved light absorption capability, the lowest resistance values, and the synergistic effect of the heterostructures.

Keywords

• kinetics
• heterostructure
• electrolyte
• spectroscopy analysis
• nyquist plot