Local Enhanced Electric Field Assisted Electrocatalytic Nitrate Reduction to Ammonia Using Ni(TCNQ)2/NF Nanostructures

Abstract

Environmentally sustainable electrocatalytic nitrate reduction (NO3RR) is a very promising method for the synthesis of ammonia at room temperature via the complex eight‐electron/nine‐proton transfer mechanism. Herein, the local electric field‐assisted electrochemical NO3RR process is proposed to identify the origin of catalytic activity and charge transfer kinetics resulting from different morphologies of the electrocatalyst. Accordingly, Ni(TCNQ)2/NF nanorods (NRs) and nanotips (NTs) are fabricated on Ni foam as electrocatalysts for the NO3RR. The Ni(TCNQ)2/NF NTs exhibits an impressive ammonia yield of up to 11286.9 µg h−1 cm−2 and a Faradaic efficiency (FE) of 83.7% at −1.0 V versus RHE, representing nearly a 2.2‐fold increase in yield compared to the Ni(TCNQ)2/NF NRs. This greater performance is attributed to the local enhanced electric field (LEEF) generated at the tip‐like Ni(TCNQ)2/NF NTs. Furthermore, a Zn–NO3− battery is developed here, and Ni(TCNQ)2/NF NTs shows a maximum power density of 2.15 mW cm−2. Experimental and computational findings demonstrate that the geometric and electrical properties of the nanostructures' shape significantly influence the electrochemical NO3RR by enhancing the kinetics of charge transfer. This study seeks to advance research on morphology‐dependent electrochemical NO3RR through the strategic control of local electric field intensity in electrocatalysts.