In-situ ammonia synthesis and energy generation via aqueous Zn-NO3 -battery

Abstract

The sustainable generation of electricity and ammonia (NH3) is essential for modern industrial advancement. Electrochemical nitrate reduction reaction (NO3RR) offers a sustainable pathway for NH₃ production, complemented by energy generation and pollution mitigation. Herein, we have utilised FeCu(1:2)S_x as a cathode catalyst in Zn-NO₃^⁻ battery to produce NH3 via NO₃RR simultaneously generating the electricity. The assembled Zn-NO₃^⁻ battery demonstrated a remarkable Faradaic efficiency (F.E.) of 98.96% for NH₃ and a power density of 5.2 mW cm^⁻2 . The real time NH3 production examined by in-situ electrochemical Raman and attenuated total reflectance-Fourier transform infrared (ATR FT-IR) spectroscopy revealed that Cu promotes NO₃⁻ adsorption and reduction to NO₂^⁻, while Fe facilitates the hydrogenation resulted at a NH₃ yield of 3.69 mg h⁻¹ cm⁻ ² at -0.9 V vs. RHE. As a proof of concept two Zn-NO₃^⁻ batteries connected in series powered 62 LEDs for over 70 h.