For
electrochemical nitrogen reduction reaction (NRR), hybridizing
transition metal (TM) compounds with nitrogen-doped carbonaceous materials
has been recognized as a promising strategy to improve the activity
and stability of electrocatalysts due to the synergistic interaction
from the TM–N–C active sites. Nevertheless, up to date,
the fundamental mechanism of this so-called synergistic electrocatalysis
for NRR is still unclear. Particularly, it remains ambiguous which
configuration of N dopants, either pyridinic N or pyrrolic N, when
coordinated with the TM, predominately contributes to this synergy.
Herein, a self-assembled three-dimensional 1T-phase MoS2 microsphere coupled with N-doped carbon was developed (termed MoS2/NC), showing an impressive NRR performance in neutral medium.
The hybridization of MoS2 and N-doped carbon can synergistically
enhance the NRR efficiency by optimizing the electron transfer of
catalyst. Acidification/blocking/poisoning experiments reveal the
decisive role of pyridinic-N–Mo bonding, rather than pyrrolic-N–Mo
bonding, in synergistically enhancing NRR electrocatalysis. The electrochemical-based in situ Fourier transform infrared spectroscopy (in situ FTIR) technology provides deep insights into the
substantial contribution of pyridinic-N–MoS2 sites
to NRR electrocatalysis and further uncover the underlying mechanism
(associative pathway) at a molecular level.