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

Abstract

A N2 fixation by the electrocatalytic nitrogen reduction reaction (NRR) from humidified air is regarded to be a critical approach for producing NH3 and reducing the globally accelerating CO2 emissions. Notwithstanding great efforts to optimize 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 (2D) 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 embedding in the Ti3C2 web strengthen 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 N2* 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.