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 H 2 O 2 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 H 2 O 2 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 H 2 O 2 (9.34 mol h –1 and 95.1%) and chlorine (9.26 mol 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. • A Janus c MOF-on- c MOF based bifunctional electrocatalyst is constructed to concurrently drive 2e − ORR and CER in seawater. • The anisotropic surface charges of the two cMOFs satisfy the distinct Cl - requirements in both reactions, while interfacial active sites enable H 2 O 2 and chlorine generation. • High production rates are achieved: 9.34 mol h –1 (H 2 O 2 ) and 9.26 mol h –1 (chlorine).