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Mimicking Hydrazine Dehydrogenase for Efficient Electrocatalytic Oxidation of N2H4 by Fe–NC
journal contribution
posted on 2020-08-17, 04:44 authored by Yan Zheng, Fei He, Mingxu Chen, Jin Zhang, Guangzhi Hu, Delong Ma, Jinghua Guo, Huailin Fan, Wei Li, Xun HuPursuing
nonprecious doped carbon with Pt-like electrocatalytic
N2H4 oxidation activity for hydrazine fuel cells
(HzFCs) remains a challenge. Herein, we present a Fe/N-doped carbon
(Fe–NC) catalyst with mesopore-rich channel and highly dispersed
Fe–N sites incorporated in N-doped carbon, as an analogue of
hydrazine dehydrogenase (HDH), showing the structure-dependent activity
for electrocatalytic oxidation of N2H4. The
maximal turnover frequency of the N2H4 oxidation
reaction (HzOR) over the Fe–N sites (62870 h–1) is 149-fold that over the pyridinic-N sites of N-doped carbon.
The Fe mass activity of HzOR and maximal power density of HzFCs driven
by Fe–NC approximately surpass those of Pt/C by 2.3 and 2.2
times, respectively. Theoretical calculation reveals that the Fe–N
sites improve the dehydrogenation process of HzOR-related intermediates.
One of the roles of the mesoporous structure in Fe–NC resembles
that of a substrate channel in HDH for enhancing the transport of
N2H4 besides exposing Fe–N sites and
improving storage capacity of HzOR-related species.