Bioinspired Multi-metallic Relay Catalyst for Efficient Nitrate Reduction and Zn-NO3– Battery Performance

Electrocatalytic nitrate reduction (e-NO3– RR) to ammonia offers an effective pathway for environmental remediation and clean energy production. However, its efficiency is often constrained by sluggish multi-electron/proton transfer and mismatched intermediate adsorption. Herein, we report a bioinspired multi-metallic cobalt copper molybdate (CCM) catalyst that overcomes these limitations through a relay-type catalytic mechanism enabled by spatially distinct metal centers. In this architecture, Cu, Co, and Mo sites cooperatively orchestrate intermediate stabilization and proton activation in successive reaction steps, thereby facilitating an efficient cascade conversion of nitrate to ammonia. As a result, the optimized CCM catalyst achieves an ammonia yield rate of 2.6 mmol h–1 cm–2 and a Faradaic efficiency up to 92%. Combined experimental and theoretical analyses identify the synergistic interplay among the multiple metal active centers as the mechanistic basis for the enhanced nitrate-to-ammonia performance. Beyond half-cell evaluation, integration of the CCM catalyst into a Zn-NO3– battery delivers an output voltage of 1.34 V and a power density of 4.1 mW cm–2, demonstrating its viability for coupled ammonia synthesis and energy generation. This study identifies multi-metallic relay catalysis as an effective strategy for efficient electrocatalytic nitrate-to-ammonia conversion.