Enhancing Reactive Oxygen Generation through Contact-Electro-Catalysis Fenton for Efficient Pollutant Degradation

Contact-electro-catalysis (CEC), which induces electron transfer via contact electrification at solid-liquid interfaces to efficiently generate reactive oxygen species (ROS), represents a promising method for the degradation of organic pollutants. However, the low concentration of ROS generated solely by electron transfer at the solid-liquid interface limits the efficient degradation of pollutants. In this study, Fe²⁺ was introduced into the CEC system to construct a Contact-electro-catalysis Fenton (CEC-Fenton) system, which enhances the concentration of ROS. The addition of Fe²⁺ provides a pathway for electron transfer, which facilitates the generation of ROS, while the Fe²⁺/Fe³⁺ redox cycling supporting the sustained production of ROS. Methyl orange (MO) was employed as a model pollutant to evaluate the catalytic degradation performance. The degradation rate of MO in the CEC-Fenton system can reach up to 0.4 min^-1, which is 33 times higher than that in the traditional CEC system. The method exhibits broad-spectrum degradation capabilities for organic pollutants with degradation rates for Methylene Blue (MB) and Rhodamine B (RhB) enhanced by factors of 4.6 and 6.1, respectively. The superior performance of this method for azo pollutants originates from protonation-induced activation of the azo bond. The superoxide anion radical (·O₂^-) was identified as the primary ROS, whose generation was significantly promoted by the introduction of Fe²⁺ ions. This project offers a method for increasing the concentration of ROS within the CEC systems.