Identifying the Dominant Role of Pyridinic-N–Mo Bonding in Synergistic Electrocatalysis for Ambient Nitrogen Reduction
Xian‐Wei Lv, Xiaolu Liu, Yujun Suo, Yuping Liu, Zhong‐Yong Yuan
Abstract
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.