Hydrothermal Self‐Assembly of Gold Nanoparticles Embed on Carbon Felt for Effective Nitrogen Reduction

Abstract

Gold‐based electrocatalysts are potential candidates for electrocatalytic nitrogen reduction reaction (e‐NRR) application due to their high conductivity and low hydrogen evolution tendency. However, the role of nonmetallic Au surfaces is not widely studied. Herein, the self‐assembly of gold nanoparticles confined in carbon felts (Au NPs@CFs) containing two different states of Au is reported, showing effective e‐NRR performance. The effects of surfactant concentration on the morphology and electrochemical performance of the Au NPs are analyzed. X‐ray photoelectron spectroscopy indicates two valence states of Au (Au0 and Au3+) in Au NPs@CFs. Interestingly, it is found that the e‐NRR properties of Au NPs@CFs enhance with the increase of Au3+ content. A typical sample Au NPs@CF‐1.0 with the highest Au3+ content exhibits the best e‐NRR performance (NH3 yield of 66.1 μg h−1 mg−1cat. and Faradaic efficiency of 24.9% at −0.3 V vs reversible hydrogen electrode), which, in part due to the presence of Au3+, is conducive to nitrogen adsorption. Theoretical calculation results find that a stable Au3+ surface can adsorb N2 strongly, which in turn can lead to energetically favorable formation of ammonia. This study provides new insights into the relation between oxidation states and performance of gold‐based electrocatalyst with high e‐NRR performance.