posted on 2024-01-04, 22:04authored byHongmei Li, Panpan Li, Yong Guo, Zhaoyu Jin
Single-atom
catalysts (SACs), specifically iron single atoms dispersed
on nitrogen-doped carbon (Fe-NC), have shown promising potential in
the electrocatalytic reduction of nitrate to ammonia (NitRR), but
there is a lack of understanding of their intrinsic activity. The
conventional measurements often overlook the intrinsic performance
of SACs, leading to significant underestimation. This study presents
an in situ electrochemical probing protocol, using two poisoning molecules
(SCN– and NO2–), to
characterize the reactivity of Fe sites in Fe-NC SACs for NitRR. The
technique aids in quantifying the yield rate of ammonia on Fe sites
and the active site number. The findings reveal the intrinsic turnover
frequency (TOF) based on the number and ammonia yield rate of Fe sites,
challenging the current understanding of SACs’ inherent performances.
This unique approach holds considerable potential for determining
the intrinsic activity of other SACs in complex reactions, opening
new avenues for the exploration of electrocatalytic processes.