Note from the field Enhanced electricity generation and degradation of the azo dye Reactive Green 19 in a photocatalytic fuel cell using ZnO/Zn as the photoanode Sin-Li Lee a , Li-Ngee Ho a, * , Soon-An Ong b , Yee-Shian Wong b , Chun-Hong Voon c , Wan Fadhilah Khalik b , Nik Athirah Yusoff b , Noradiba Nordin a a School of Materials Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia b Water Research Group (WAREG), School of Environmental Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia c Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia article info Article history: Received 23 September 2015 Received in revised form 22 March 2016 Accepted 30 March 2016 Available online xxx Keywords: Photocatalytic fuel cell ZnO/Zn photoanode Degradation Electricity generation Wastewater treatment Electrolyte abstract 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 photo- catalytic 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 ef- ficiency 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. UltravioleteVisible spectroscopy and chemical oxygen demand analysis deter- mined 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. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Various wastewater treatment technologies have been employed to treat dye-containing wastewater. Although conven- tional biological processes degrade dye effluents, it has been found that these technologies are ineffective due to the recalcitrant nature of synthetic dyes (Wang et al., 2011). The photocatalytic fuel cell (PFC) is under consideration as a potential alternative system due to its ability to recover energy from photocatalytic degradation pro- cesses. Numerous studies have been reported on PFC systems based on the TiO 2 nanoparticulate film photoanode (Liu et al., 2011a; Li et al., 2013a) due to the ability of TiO 2 to non-selectively degrade a wide range of organic substances (Cheng et al., 2015; Chong et al., 2015; Shen et al., 2015). Different types of semiconductors such as WO 3 (Chen et al., 2012, 2014), CdS (Liu et al., 2011b; Wu et al., 2015) and CuO (Yang et al., 2014) have also been investigated as photo- anodes in PFC systems. However, little work has been reported on the application of zinc oxide (ZnO) as a functional photoanode in PFC systems. ZnO is a photocatalyst of interest as its reactivity is comparable to TiO 2 (Di Paola et al., 2012). Moreover, the addition of suitable supporting electrolytes is another important concern in PFC systems. Several researchers have reported that the addition of supporting electrolytes can enhance the mineralization process (Ca~ nizares et al., 2009; Panizza and Cerisola, 2007) and electricity generation (Li et al., 2015). Sodium sulfate (Na 2 SO 4 ) is the most commonly used electrolyte in PFC systems (Liu et al., 2011a; Iyatani et al., 2012; Wang et al., 2014). In this study, the performance of a PFC based on the ZnO/Zn photoanode was evaluated. The effects of variables such as different types of supporting electrolytes and initial dye concentration on electricity generation and RG 19 degradation were investigated. * Corresponding author. E-mail addresses: holingee@yahoo.com, lnho@unimap.edu.my (L.-N. Ho). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro http://dx.doi.org/10.1016/j.jclepro.2016.03.169 0959-6526/© 2016 Elsevier Ltd. All rights reserved. Journal of Cleaner Production xxx (2016) 1e6 Please cite this article in press as: Lee, S.-L., et al., Enhanced electricity generation and degradation of the azo dye Reactive Green 19 in a photocatalytic fuel cell using ZnO/Znas the photoanode, Journal of Cleaner Production (2016), http://dx.doi.org/10.1016/j.jclepro.2016.03.169