A Janus conductive MOF-on-conductive-MOF heterostructure enables simultaneous production of H₂O₂ and active chlorine by seawater electrolysis

Seawater electrolysis is an ideal strategy for the simultaneous production of H₂O₂ and active chlorine, but it has yet to be realized. In this study, a rationally designed conductive metal–organic framework ( c MOF)-on- c MOF electrocatalyst is presented for seawater electrolysis. The negatively charged Co- c MOF and positively charged Cu- c MOF units respectively facilitate Cl⁻ repulsion at the cathode and Cl⁻ enrichment at the anode. Moreover, the formation of interfacial Cu–O–Co bonds generates anisotropic active sites with tailored electronic structures for H₂O₂ and chlorine generation. Additionally, the c MOF-on- c MOF design provides a built-in electric field and enhanced charge transfer. Consequently, the Janus electrocatalyst delivers high production rates and Faradaic efficiencies for both H₂O₂ (9.34 mol catg⁻¹ h⁻¹ and 95.1%) and chlorine (9.26 mol catg⁻¹ h⁻¹ and 94.3%), with a long-term stability of over 100 h in an integrated seawater electrolyzer. This work provides insights into the design of both advanced materials and electrocatalytic systems for the production of value-added chemicals in seawater.