Ruthenium Anchored Laser‐Induced Graphene as Binder‐Free and Free‐Standing Electrode for Selective Electrosynthesis of Ammonia from Nitrate

Abstract

Abstract Developing effective electrocatalysts for the nitrate reduction reaction (NO3RR) is a promising alternative to conventional industrial ammonia (NH3) synthesis. Herein, starting from a flexible laser‐induced graphene (LIG) film with hierarchical and interconnected macroporous architecture, a binder‐free and free‐standing Ru‐modified LIG electrode (Ru‐LIG) is fabricated for electrocatalytic NO3RR via a facile electrodeposition method. The relationship between the laser‐scribing parameters and the NO3RR performance of Ru‐LIG electrodes is studied in‐depth. At −0.59 VRHE, the Ru‐LIG electrode exhibited the optimal and stable NO3RR performance (NH3 yield rate of 655.9 µg cm−2 h−1 with NH3 Faradaic efficiency of up to 93.7%) under a laser defocus setting of +2 mm and an applied laser power of 4.8 W, outperforming most of the reported NO3RR electrodes operated under similar conditions. The optimized laser‐scribing parameters promoted the surface properties of LIG with increased graphitization degree and decreased charge‐transfer resistance, leading to synergistically improved Ru electrodeposition with more exposed NO3RR active sites. This work not only provides a new insight to enhance the electrocatalytic NO3RR performance of LIG‐based electrodes via the coordination with metal electrocatalysts as well as identification of the critical laser‐scribing parameters but also will inspire the rational design of future advanced laser‐induced electrocatalysts for NO3RR.

Keywords

• ammonia
• electrocatalysis
• laser‐induced graphene
• nitrate reduction reaction
• ruthenium