Enhanced electricity generation and degradation of the azo dye Reactive Green 19 in a photocatalytic fuel cell using ZnO/Zn as the photoanode

• A sustainable system has been developed to recover energy from organic wastewater.
• A novel ZnO/Zn plate was used as the photoanode in the photocatalytic fuel cell.
• Electricity generation was greatly affected by different supporting electrolytes.
• NaCl as the supporting electrolyte afforded the highest dye degradation efficiency.

The photocatalytic fuel cell is under consideration as a potential alternative system for recovering energy from the photocatalytic degradation of organic pollutants. In this study, a single-chambered photocatalytic fuel cell using ZnO/Zn as the photoanode and platinum loaded carbon as the cathode was constructed, and Reactive Green 19 was used as the organic pollutant. Operating parameters such as aeration, organic pollutant and photoanode were evaluated. Electricity generation and degradation efficiency were investigated in the presence of different supporting electrolytes such as sodium chloride, sodium sulfate and magnesium sulfate. The results indicated that the addition of sodium sulfate as the supporting electrolyte afforded the highest short circuit current: 2.64 mA cm−2 and a maximum power density of 1.2696 mW cm−2. However, in terms of photocatalytic degradation, the presence of sodium chloride as the supporting electrolyte led to the highest dye degradation efficiency. In addition to electrolytes, the voltage output and degradation rate were significantly affected by different initial concentrations of dye. Ultraviolet–Visible spectroscopy and chemical oxygen demand analysis determined that 100% decolorization and 92% mineralization of 10 mg L−1 of dye could be achieved after 8 h using sodium chloride as the supporting electrolyte in an aerated photocatalytic fuel cell.

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