Two-dimensional Cu Plates with Steady Fluid Fields for High-rate Nitrate Electroreduction to Ammonia and Efficient Zn-Nitrate Batteries

Nitrate electroreduction reaction (eNO₃⁻RR) to ammonia (NH₃) provides a promising strategy for nitrogen utilization, while achieving high selectivity and durability at an industrial scale has remained challenging. Herein, we demonstrated that the performance of eNO₃⁻RR could be significantly boosted by introducing two-dimensional Cu plates as electrocatalysts and eliminating the general carrier gas to construct a steady fluid field. The developed eNO₃⁻RR setup provided superior NH₃ Faradaic efficiency (FE) of 99 %, exceptional long-term electrolysis for 120 h at 200 mA cm⁻², and a record-high yield rate of 3.14 mmol cm⁻² h⁻¹. Furthermore, the proposed strategy was successfully extended to the Zn-nitrate battery system, providing a power density of 12.09 mW cm⁻² and NH₃ FE of 85.4 %, outperforming the state-of-the-art eNO₃⁻RR catalysts. Coupled with the COMSOL multiphysics simulations and in situ infrared spectroscopy, the main contributor for the high-efficiency NH₃ production could be the steady fluid field to timely rejuvenate the electrocatalyst surface during the electrocatalysis.
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