Flow-Through Electrochemical Membrane Reactor with a Self-Supported Carbon Membrane Electrode for Highly Efficient...

In situ electroreduction of O₂ to H₂O₂ by using electrons as reagents is known as a green process, which is highly desirable for environmental remediation and chemical industries. However, the development of a cost-effective electrode with superior H₂O₂ synthesis rate and stability is challenging. A self-supported carbon membrane (CM) was prepared in this study from activated carbon and phenolic resin by carbonization under a H₂ atmosphere. It was employed as the cathode to build a flow-through electrochemical membrane reactor (FT-ECMR) for electrosynthesis of H₂O₂. The results showed that the CM had a small pore size (34 nm), a high porosity (42.3%), and a high surface area (450.7 m² g^-1). In contrast to most of the state-of-the-art self-supported carbon electrode reported in the previous works, the FT-ECMR exhibited a high concentration of continuous and stable H₂O₂ electrosynthesis (1042 mg L^-1) as well as a H₂O₂ synthesis rate of 5.21 mg h^-1 cm^-2. It had also demonstrated a high oxygen conversion (0.37%) and current efficiency (88%). The outstanding performance of the FT-ECMR for H₂O₂ synthesis was attributed to the enhanced mass transfer of the reactor, the existence of a relatively high surface area of CM, and the abundant disordered carbon structures (sp³-C, defects, and edges). In conclusion, our work highlighted using the FT-ECMR with the CM to synthesize H₂O₂ efficiently and cost-effectively.