Highly efficient N-2 fixation catalysts: transition-metal carbides M2C (MXenes)

doi:10.1039/c9nr09157b

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	Highly efficient N-2 fixation catalysts: transition-metal carbides M2C (MXenes)
	Wang, Shuo ; Li, Bo ; Li, Lei ; Tian, Ziqi ; Zhang, Qiuju ; Chen, Liang ; Zeng, Xiao Cheng
刊名	NANOSCALE
	2020
卷号	12 期号:2 页码:538-547
关键词	NITROGEN-FIXATION AMMONIA-SYNTHESIS REDUCTION REACTION AMBIENT CONDITIONS ELECTROCATALYST CONVERSION DINITROGEN NANOSHEETS MONOLAYER DESIGN
DOI	10.1039/c9nr09157b
英文摘要	The development of highly efficient metal or metal compound electrocatalysts under mild conditions has always been a challenging task for N-2 reduction. Herein, we show that pristine two-dimensional (2D) MXenes are promising N-2 electroreduction catalysts due in part to the availability of multiple active sites per unit area. We systematically explore a series of 3d, 4d and 5d-transition metal M2C (M = Sc, Ti, V, Cr, Mn, Fe, Zr, Nb, Mo, Ta and Hf) MXenes and compute their limiting potentials for the N-2 reduction reaction (NRR). We find that 4d(4)-Mo2C gives rise to the lowest free-energy barrier (Delta G) of 0.46 eV, among the synthesized M2C MXenes as of today. More importantly, we find that two hypothetical MXenes, 3d(5)-Mn2C and 3d(6)-Fe2C, possess even lower Delta G of 0.28 and 0.23 eV, respectively, compared to the state-of-the-art 4d(4)-Mo2C, thereby likely being more efficient NRR catalysts. The N-2 capture strength, a key parameter of the potential-limiting step, is found to be closely related to the d-electron arrangement on the occupied and empty spin-split d-orbitals. Hence, the excellent NRR performance of Mn2C and Fe2C can be attributed to the desirable half-filled 3d(5) or 3d(6) electron arrangements. The adsorption of N-2 on Mn2C results in the donation of 1 sigma electrons to the empty spin-down 3d orbitals of Mn. The donated electrons weaken the N-2 adsorption strength and lower the energy barrier of the potential-limiting step of hydrogenation. The insights obtained from this comprehensive study offer guidance to design new and efficient electrocatalysts for N-2 fixation.
学科主题	Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics
内容类型	期刊论文
源URL	[http://ir.nimte.ac.cn/handle/174433/20201]
专题	2020专题
作者单位	1.Chen, L (corresponding author), Chinese Acad Sci, Ningbo Inst Mat Technol & Engn, Ningbo 315201, Zhejiang, Peoples R China. 2.Zeng, XC (corresponding author), Univ Nebraska, Dept Chem, Lincoln, NE 68588 USA. 3.Zhang, Q 4.Chen, L (corresponding author), Univ Chinese Acad Sci, Beijing 100049, Peoples R China.
推荐引用方式 GB/T 7714	Wang, Shuo,Li, Bo,Li, Lei,et al. Highly efficient N-2 fixation catalysts: transition-metal carbides M2C (MXenes)[J]. NANOSCALE,2020,12(2):538-547.
APA	Wang, Shuo.,Li, Bo.,Li, Lei.,Tian, Ziqi.,Zhang, Qiuju.,...&Zeng, Xiao Cheng.(2020).Highly efficient N-2 fixation catalysts: transition-metal carbides M2C (MXenes).NANOSCALE,12(2),538-547.
MLA	Wang, Shuo,et al."Highly efficient N-2 fixation catalysts: transition-metal carbides M2C (MXenes)".NANOSCALE 12.2(2020):538-547.