A Dual Photoelectrode System for Solar-Driven Saltwater Electrolysis: Simultaneous Production of Chlorine and Hydrogen

Abstract

Chlorine plays an essential role in various industries, such as wastewater treatment, disinfection, plastics, and pharmaceuticals, contributing to a significant global demand. Traditional methods of chlorine production, including chemical reactions involving manganese dioxide, potassium chlorate, and potassium permanganate, as well as the electrolysis of saturated salt solutions, are associated with safety and efficiency concerns. This study introduces a novel approach for the photoelectrocatalytic production of chlorine gas through the oxidation of chloride ions in potassium chloride solutions using a dual semiconductor photoelectrode system composed of TiO2 and Cu2O. By harnessing solar energy, this system enables the concurrent, safe, and efficient production of both chlorine and hydrogen gases. The TiO2 photoelectrode is employed for chlorine production, while Cu2O is used for hydrogen generation. The dual photoelectrode system mimics the process of electrolytic seawater electrolysis, offering a promising alternative to conventional methods. Through linear sweep voltammetry, current–time tests, and electrochemical impedance spectroscopy, we demonstrate the effectiveness of this approach, supported by a detailed analysis of the energy band structure. Additionally, the material’s characteristics were verified using X-ray diffraction (XRD) and scanning electron microscopy (SEM). This work not only provides a safer and more efficient method for chlorine production but also highlights the potential of solar-powered photoelectrocatalysis in large-scale applications. These findings point toward a sustainable and environmentally friendly direction for chlorine production under simulated seawater conditions, with significant implications for renewable energy-driven industrial processes.