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

ABSTRACT

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.