Defect‐Enhanced CO2 Reduction Catalytic Performance in O‐Terminated MXenes

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Defect‐Enhanced CO2 Reduction Catalytic Performance in O‐Terminated MXenes
Title:
Defect‐Enhanced CO2 Reduction Catalytic Performance in O‐Terminated MXenes
Journal Title:
ChemSusChem
Publication Date:
19 August 2020
Citation:
H. Chen, A. D. Handoko, T. Wang, J. Qu, J. Xiao, X. Liu, D. Legut, Z. Wei Seh, Q. Zhang, ChemSusChem 2020, 13, 5690.
Abstract:
Electrochemical carbon dioxide reduction reaction (CO2RR) represents a promising way to generate fuels and chemical feedstock sustainably. Recently, studies have shown that two‐dimensional metal carbides and nitrides (MXenes) can be promising CO2RR electrocatalysts due to the alternating −C and −H coordination with intermediates that decouples scaling relations seen on transition metal catalysts. However, further by tuning the electronic and surface structure of MXenes it should still be possible to reach higher turnover number and selectivities. To this end, defect engineering of MXenes for electrochemical CO2RR has not been investigated to date. In this work, first‐principles modelling simulations are employed to systematically investigate CO2RR on M2XO2‐type MXenes with transition metal and carbon/nitrogen vacancies. We found that the −C‐coordinated intermediates take the form of fragments (e. g., *COOH, *CHO) whereas the −H‐coordinated intermediates form a complete molecule (e. g., *HCOOH, *H2CO). Interestingly, the fragment‐type intermediates become more strongly bound when transition‐metal vacancies are present on most MXenes, while the molecule‐type intermediates are largely unaffected, allowing the CO2RR overpotential to be tuned. The most promising defective MXene is Hf2NO2 containing Hf vacancies, with a low overpotential of 0.45 V. More importantly, through electronic structure analysis it could be observed that the Fermi level of the MXene changes significantly in the presence of vacancies, indicating that the Fermi level shift can be used as an ideal descriptor to rapidly predict the catalytic performance of defective MXenes. Such an evaluation strategy is applicable to other catalysts beyond MXenes, which could enhance high throughput screening efforts for accelerated catalyst discovery.
License type:
PublisherCopyrights
Funding Info:
Q.F.Z. was supported by National Key Research and Development Program of China (No. 2017YFB0702100), Beijing Natural Science Foundation (2192029) and Technology Foundation for Selected Overseas Chinese Scholar, Ministry of Human Resources and Social Security of China. Z.W.S. was supported by the Singapore National Research Foundation (NRF-NRFF2017-04). D. L. was supported by the European Regional Development Fund in the IT4Innovations national supercomputing center - path to exascale project, project number CZ.02.1.01/0.0/0.0/16_013/0001791 within the Operational Programme Research, Development and Education and SGS No. SP2020/150.
Description:
This is the peer reviewed version of the following article: H. Chen, A. D. Handoko, T. Wang, J. Qu, J. Xiao, X. Liu, D. Legut, Z. Wei Seh, Q. Zhang, ChemSusChem 2020, 13, 5690., which has been published in final form at https://doi.org/10.1002/cssc.202001624. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
ISSN:
1864-564X
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