CaltechAUTHORS
  A Caltech Library Service

Development of a Mechanically Flexible 2D-MXene Membrane Cathode for Selective Electrochemical Reduction of Nitrate to N₂: Mechanisms and Implications

Li, Yang and Ma, Jinxing and Waite, T. David and Hoffmann, Michael R. and Wang, Zhiwei (2021) Development of a Mechanically Flexible 2D-MXene Membrane Cathode for Selective Electrochemical Reduction of Nitrate to N₂: Mechanisms and Implications. Environmental Science and Technology, 55 (15). pp. 10695-10703. ISSN 0013-936X. doi:10.1021/acs.est.1c00264. https://resolver.caltech.edu/CaltechAUTHORS:20210625-222301100

[img] PDF - Supplemental Material
See Usage Policy.

3MB

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20210625-222301100

Abstract

The contamination of water resources by nitrate is a major problem. Herein, we report a mechanically flexible 2D-MXene (Ti₃C₂T_x) membrane with multilayered nanofluidic channels for a selective electrochemical reduction of nitrate to nitrogen gas (N₂). At a low applied potential of −0.8 V (vs Ag/AgCl), the MXene electrochemical membrane was found to exhibit high selectivity for NO₃⁻ reduction to N₂ (82.8%) due to a relatively low desorption energy barrier for the release of adsorbed N₂ (*N₂) compared to that for the adsorbed NH₃ (*NH₃) based on density functional theory (DFT) calculations. Long-term use of the MXene membrane for treating 10 mg-NO₃-N L⁻¹ in water was found to have a high faradic efficiency of 72.6% for NO₃⁻ reduction to N₂ at a very low electrical cost of 0.28 kWh m⁻³. Results of theoretical calculations and experimental results showed that defects on the MXene nanosheet surfaces played an important role in achieving high activity, primarily at the low-coordinated Ti sites. Water flowing through the MXene nanosheets facilitated the mass transfer of nitrate onto the low-coordinated Ti sites with this enhancement of particular importance under cathodic polarization of the MXene membrane. This study provides insight into the tailoring of nanoengineered materials for practical application in water treatment and environmental remediation.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.est.1c00264DOIArticle
ORCID:
AuthorORCID
Ma, Jinxing0000-0002-5087-3972
Waite, T. David0000-0002-5411-3233
Hoffmann, Michael R.0000-0001-6495-1946
Wang, Zhiwei0000-0001-6729-2237
Alternate Title:Development of a Mechanically Flexible 2D-MXene Membrane Cathode for Selective Electrochemical Reduction of Nitrate to N2: Mechanisms and Implications
Additional Information:© 2021 American Chemical Society. Received: January 13, 2021; Revised: June 4, 2021; Accepted: June 4, 2021. We thank the National Natural Science Foundation of China (grants 51838009 and 51925806) and the National Key Research and Development Program of China (grant 2019YFC0408200) for the financial support of the work. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China51838009
National Natural Science Foundation of China51925806
National Key Research and Development Program of China2019YFC0408200
Subject Keywords:nitrate reduction, MXene membrane, electrochemical reduction, nanofluidic channels, membrane filtration, water treatment
Issue or Number:15
DOI:10.1021/acs.est.1c00264
Record Number:CaltechAUTHORS:20210625-222301100
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210625-222301100
Official Citation:Development of a Mechanically Flexible 2D-MXene Membrane Cathode for Selective Electrochemical Reduction of Nitrate to N2: Mechanisms and Implications. Yang Li, Jinxing Ma, T. David Waite, Michael R. Hoffmann, and Zhiwei Wang. Environmental Science & Technology 2021 55 (15), 10695-10703; DOI: 10.1021/acs.est.1c00264
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109587
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Jun 2021 23:09
Last Modified:09 Aug 2021 21:45

Repository Staff Only: item control page