Enhanced Rhodamine B and coking wastewater degradation and simultaneous electricity generation via anodic g-C3N4/Fe0(1%)/TiO2 and cathodic WO3 in photocatalytic fuel cell system under visible light irradiation

Abstract

Degradation of pollutants can be integrated with electricity generation in Photocatalytic fuel cell under light irradiation or self-powered fuel cell in the dark. In fuel cell driven by electrode reactions, the electrode reduction and oxidation transforms chemical energy in pollutants into electrical energy. In this work, Rhodamine B and coking wastewater were treated, using an efficient Z-scheme g-C3N4/Fe0(1%)/TiO2 as an anodic catalyst and WO3 as a cathodic catalyst. After 100 min of reaction in a single chamber fuel cell with 10 Ω of external resistance, in 0.05 M Na2SO4 electrolyte, the paired stainless-steel electrodes loaded respectively with g-C3N4/Fe0(1%)/TiO2 and WO3, degraded 98% Rhodamine B and generated 0.95 V cell voltage under 50 W visible-light irradiation, while removed 60% RhB and generated 0.5 V without light. To investigate the PFC performance of g-C3N4/Fe0(1%)/TiO2 in treating real coking wastewater, at optimal pH 2, 91% chemical oxygen demand (COD) and 89% total organic carbon (TOC) were removed and generated 0.3 V cell voltage. The influence of pH on photocatalytic degradation performance and cell voltage are evaluated. The high cell voltage is attributed to the very low impedance of the g-C3N4/Fe0(1%)/TiO2 loaded anode. The excellent electrochemical properties of paired electrodes help in generating higher current density, due to the increased photocatalyst activity of the tridimensional catalyst as proved by electron spinning resonance spectrum, photoluminescence, and Electric Impedance Spectrum analysis.