Elucidating the electro-catalytic oxidation of hydrazine over carbon nanotube-based transition metal single atom catalysts
Jin Zhang, Yaxin Wang, Chujie Yang, Sian Chen, Zheng Jian Li, Yi Cheng, Haining Wang, Yan Xiang, Shanfu Lu, Shuangyin Wang
Abstract
Elucidating the reaction mechanism of hydrazine oxidation reaction (HzOR) over carbon-based catalysts is highly propitious for the rational design of novel electrocatalysts for HzOR. In present work, isolated first-row transition metal atoms have been coordinated with N atoms on the graphite layers of carbon nanotubes via a M-N4-C configuration (MSA/CNT, M=Fe, Co and Ni). The HzOR over the three single atom catalysts follows a predominant 4-electron reaction pathway to emit N2 and a negligible 1-electron pathway to emit trace of NH3, while their electrocatalytic activity for HzOR is dominated by the absorption energy of N2H4 on them. Furthermore, FeSA/CNT reverses the passivation effect on Fe/C and shows superior performance than CoSA/CNT and NiSA/CNT with a recorded high mass activity for HzOR due to the higher electronic charge of Fe over Co and Ni in the M-N4-C configuration and the lowest absorption energy of N2H4 on FeSA/CNT among the three MSA/CNT catalysts.