Unique Hollow Ni-Fe@MoS2 Nanocubes with Boosted Electrocatalytic Activity for N2 Reduction to NH3
Nanostructure tailoring is being thought as an efficient strategy to design high-performance electrocatalysts for improving electrocatalytic properties by exposing more active sites and promoting rapid electron transfer. Unfortunately, well-constructed morphology of nanomaterials on the nitrogen reduction reaction (NRR) at ambient conditions is urgently insufficient, and the yields rate and Faradaic efficiency are still not high. Herein, NiFe-MoS2 nanocubes (NiFe@MoS2 NCs) are successfully synthesized derived from the corresponding Prussian blue analog self-templating strategy. Owing to this four-pointed star face-dependent hollow structure and trimetallic synergistic interactions, it largely exposes abundant active sites, making it present superb electrocatalytic performance for N2 conversion to NH3. In 0.1 M Na2SO4 electrolyte, this as-prepared Ni-Fe@MoS2 NCs exhibits significant NH3 yield of 128.17 μg h-1 mgcat.-1 and satisfied Faradaic efficiency of 11.34% at -0.3 V vs. reversible hydrogen electrode (RHE) operation at 40℃. The stability of the catalyst was performed by 20-hour continuous N2 reduction with a constant current density. The possible NRR catalytic paths, mechanism and electrons transfer paths are elucidated in detail by in situ electrochemical-Fourier transform infrared spectroscopy combined with density functional theory calculations. This work offers new inspirations to the development of various cost-effective electrocatalysts for N2 fixation.