Preparation and functionalization of free-standing nitrogen-doped carbon-based catalyst electrodes for electrocatalytic N2 fixation

Abstract

Nitrogen-doped carbon-based materials have been recently explored as promising electrocatalysts for N2 fixation. Herein, a nitrogen-doped carbon film as a self-standing electrode is synthesized through a novel and scalable strategy. After the film synthesis, a thin layer of Au nanoparticles is deposited, significantly enhancing the performance of such films in electrocatalytic N2 reduction. Owing to the exposed active sites and unique free-standing structure, it shows desirable performance towards electrochemical N2 fixation with a high Faradaic efficiency of 6.4 %, and a NH3 production rate of 18.3 μg h−1 cm−2 at a low given potential of -0.05 V vs. reversible hydrogen electrode. Such performance is superior in comparison with Au-nanoparticles-modified nitrogen-doped carbon powder. Further comparison of nitrogen-doped carbon film and nitrogen-doped carbon powder also demonstrates the benefits of the free-standing structure in comparison to film-based materials in terms of charge transfer and active sites per electrode surface area.