Synergistic Electrocatalytic Nitrogen Reduction Enabled by Confinement of Nanosized Au Particles onto a Two-Dimensional Ti₃C₂ Substrate

Abstract

A N2 fixation by the electrocatalytic nitrogen reduction reaction from humidified air is regarded to be a critical tool for producing NH3 and reducing the globally accelerating CO2 emissions. Notwithstanding great efforts to improve catalyst activity and selectivity, promoting catalyst accessibility to high N2 concentrations to ensure that active sites fulfill their function should be a promising design direction. Here, Au nanoparticles are firmly anchored through atomic O on the surface of two-dimensional Ti3C2 using an ultrasound reduction process. Akin to the conspicuous role of the web in the predatory process of spiders, N2 adsorption experiments primarily suggest that a Ti3C2 “web” is beneficial for extraction of N2 from air, and embedding high valence-state Au clusters in the Ti3C2 “web” strengthens the chemical bonding effect toward N2 molecules. The high energy of N2 adsorption on the interface between gold clusters and Ti3C2 is the driving force for weakening triple NN bonds, and thereby the activation energy barrier is lowered via effective stabilization of N2H* species and destabilizing NH2NH2* under an alternative pathway. With Au loading content of ∼0.94%, Au/Ti3C2 exhibits an outstanding average yield of 30.06 μg h–1 mg–1 for NH3 production, with a high Faraday efficiency of 18.34% at −0.2 V.

Exploration and Investigation of Periodic Elements for Electrocatalytic Nitrogen Reduction

“…To further enhance the NRR activity, gold particles were anchored on 2-D Ti 3 C 2 substrate via atomic O. Herein, Au-Ti 3 C 2 acts as web which effectively adsorb N 2 and effectively N 2 was activated by low energy barrier. [43] As a result, it has manifested efficiency as high as 18.34% in 0.1 m HCl at −0.2 V with 30.06 µg h −1 mg cat −1 ammonia yield rate. Similarly, titanium oxynitride containing high oxygen content was explored as NRR catalyst by Zhang and co-workers.…”

Recent Progress in MXene‐Based Materials: Potential High‐Performance Electrocatalysts

“…Besides, Cheng et al [22] also found that a single Mo atom immobilized on 2D Ti 2 NO 2 MXene acts as an electrocatalyst for NRR and exhibits good performance. Liu et al [79] applied nano-sized Au particles onto the surface of 2D Ti 3 C 2 by ultrasonic reduction method, and confirmed that a large amount of N 2 adsorption energy at the interface between high-valence gold clusters and Ti 3 C 2 is the driving force for weakening the NN triple bond. When the Au content of Au/Ti 3 C 2 is 0.94%, the average yield of NH 3 production is 30.06 µg h −1 mg −1 , and the FE is 18.34% at −0.2 V versus RHE.…”

Two-dimensional metal carbides and nitrides (MXenes): preparation, property, and applications in cancer therapy

“…Unterminated (bare) MXenes are metallic with a high density of states at the Fermi level. The electronic properties of MXenes are significant depending on the properties of M, X elements and surface terminations [11,19,[55][56][57][58][59]. Upon surface modification, some of the MXenes are tuned from metallic to semiconducting.…”