Promoting N2 electroreduction to ammonia by fluorine-terminating Ti3C2Tx MXene

Yu Ding,Si Li,Abdullah M Al-Enizi,Anxiang Guan,Junbo Zhang,Lijuan Zhang,Qihao Wang,Linping Qian,Gengfeng Zheng

doi:10.1186/s40580-021-00264-9

Yu Ding, Si Li + Show 7 more

Open Access

https://doi.org/10.1186/s40580-021-00264-9

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Journal: Nano Convergence	Publication Date: May 10, 2021
Citations: 15	License type: open-access

Affiliation: Fudan University, King Saud University

Abstract

Two-dimensional MXene-based materials are potential of presenting unique catalytic performances of electrocatalytic reactions. The surface functionalization of MXene-based catalysts is attractive for developing efficient electrocatalysts toward nitrogen reduction reaction. Herein, we reported a Ti3C2Tx MXene with a medium density of surface functionalized fluorine terminal groups, as an excellent N2 reduction reaction electrocatalyst with enhanced adsorption and activation of N2. The Ti3C2Tx MXene catalyst showed a production rate of ammonia as 2.81 × 10–5 μmol·s−1·cm−2, corresponding to a partial current density of 18.3 μA·cm−2 and a Faradic efficiency of 7.4% at − 0.7 V versus reversible hydrogen electrode in aqueous solutions at ambient conditions, substantially exceeding similar Ti3C2Tx MXene catalysts but with higher or lower densities of surface fluorine terminal groups. Our work suggests the capability of developing surface functionalization toolkit for enhancing electrochemical catalytic activities of two-dimensional MXene-based materials.

Highlights

Artificial nitrogen fixation to ammonia (NH3) plays a critical role in fabricating agricultural fertilizers and maintaining the earth’s ecosystems [1,2,3]
The surface of Ti3C2Tx MXene was covered by different terminal groups, mainly including O-containing groups (e.g.–O, − OH) and fluorine groups [29]
Energy-dispersive X-ray spectroscopy (EDS) elemental mapping analysis showed that Ti, C, O, and F elements were evenly distributed on the obtained Ti3C2Tx MXene (Fig. 1c)

Summary

Introduction

Artificial nitrogen fixation to ammonia (NH3) plays a critical role in fabricating agricultural fertilizers and maintaining the earth’s ecosystems [1,2,3]. Due to the combined effects including hydrogenation and N 2 activation, T i3C2Tx MXene with a medium F-terminal group density (designated as Ti3C2Tx-medium F) exhibited the optimal electrocatalytic N2RR performances. To modify the density of fluorine terminal groups on the surface of T i3C2Tx MXene, different fluorine-containing acids were used.

Results

Conclusion