Scientists from the Institute of Solid State Physics, Hefei Institutes of Physical Science developed a new way to enhance ambient ammonia electrosynthesis performance. Their findings were published in Advanced Energy Materials.

Electrocatalytic reduction of N₂ to NH₃ under ambient conditions has been considered as a promising alternative to the energy and resource intensive Haber–Bosch process.

However, a high yield of NH₃ via electrocatalytic NRR is extremely challenge as it requires an electrocatalyst with high catalytic activity to efficiently break the stable triple-bonds of N₂  and simultaneously suppress the competitive hydrogen evolution reaction (HER).

It is well known that the 2D-MoS₂ is a typical electrocatalyst for HER. 2D-MoS₂ also has been reported as an electrocatalyst with NRR properties and can be significantly improved by structural modifications.

However, their studies were mainly focused on the influence of structural and surface defects on NRR catalytic activity rather than suppressing the concurrently occurred HER.

Herein, the team reported the in-operando created strong Li–S interactions to empower the S-rich MoS₂ nanosheets with superior NRR catalytic activity and HER suppression functionality. A NH₃ yield rate and a faradaic efficiency (FE) in presence of strong Li–S interactions could be achieved more than 8 and 18 times by the same electrocatalyst in the absence of Li–S interactions.

The DFT calculation results also confirmed that the strong Li-S interactions could occur at S-edge sites of MoS₂ and such in operando-induced interactions could effectively suppress HER process, enhance N₂ adsorption and activate N-N bonds to boost NRR performance.

The reported in-operando formation of catalytic active structures via catalyst– electrolyte interactions opens a new way to design and develop catalysts and catalysis systems.

Link to the paper: Dramatically Enhanced Ambient Ammonia Electrosynthesis Performance by In‐Operando Created Li–S Interactions on MoS₂Electrocatalyst

(a) Schematic illustration of the synthesis process of MoS₂/BCCF; (b) TEM image of MoS₂ nanosheets (insets: HRTEM images of MoS₂); (c) NRR performance of MoS₂/BCCF in N₂-saturated 0.1 M Li₂SO₄ solution at various potentials; (d) ⁷Li solid-state NMR spectra of the standard ⁷Li₂SO₄ and MoS₂/BCCF after NRR in 0.1 M 7Li₂SO₄ electrolyte; (e) High-resolution S 2p XPS spectra of the as-synthesized MoS₂/BCCF and MoS₂/BCCF after different NRR time; (f) Schematic illustration the NRR of MoS₂/BCCF with Li–S interactions. (Image by LIU Yanyan)

Contact:

ZHOU Shu

Hefei Institutes of Physical Science (http://english.hf.cas.cn/)

Email: zhous@hfcas.ac.cn