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The term MXenes (pronounced ‘maxenes’) was first introduced in 2011 by Naguib et al. to indicate the exfoliated material obtained from a MAX bulk phase. A MAX phase (general formula Mx+1AXn, with n = 1–4) is a ternary carbide or nitride (X = C, N), with M an early transition metal and A an element from groups 13 or 14 of the periodic table. An important MAX phase material is Ti3AlC2 . To make the corresponding MXenes, Naguib et al. treated it with HF, which extracts the Al layer from the crystal structure, exposing the Ti atoms to possible chemical functionalization. In the first report, functionalization consisted of either F atoms or OH groups (after reacting with water). A sonication step then led to exfoliation into nanometer-thick crystal layers of the corresponding Ti3C2 MXene (general formula Mx+1Xn).
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This content will become publicly available on July 22, 2026
Computational discovery of a novel double transition metal nitride MXene and its applications as an anchoring and catalytic material in Li–Se batteries
Double transition metal (DTM) nitride MXenes offer enhanced electrical conductivity and tunable catalytic properties compared to conventional carbide-based MXenes. In this study, we employed first-principles density functional theory (DFT) calculations to discover and computationally validate a novel DTM nitride MXene, Nb2TiN2, derived from its MAX phase precursor and investigated its potential as an anchoring material (AM) for Li–Se batteries. This newly proposed MXene expands the compositional landscape of DTM nitrides and opens new avenues for functional material design. We performed a comprehensive analysis of the thermodynamic and electronic properties of Nb2TiAlN2, and the MAX phase precursor to Nb2TiN2 to assess its structural stability and exfoliation potential. Exfoliation energy calculations confirmed the feasibility of synthesizing Nb2TiN2 from Nb2TiAlN2. We then explored the functionalized form, Nb2TiN2S2, evaluating its capability to serve as an effective anchoring material (AM) in Li–Se batteries by analyzing the reaction mechanisms and kinetics of the selenium reduction reaction (SeRR). Our results indicate that Nb2TiN2S2 exhibits a strong binding affinity for lithium polyselenides (Li2Sen), effectively suppressing the shuttle effect. Gibbs free energy calculations for the rate-limiting step of the SeRR reveal favorable kinetics and reduced reaction barriers. Overall, this study provides a detailed evaluation of the structural and electronic properties of a newly proposed DTM nitride MXene and its S-functionalized derivative and the catalyzing effect of Nb2TiN2S2 in accelerating the reaction kinetics in Li–Se batteries. These findings underscore the potential importance of the further exploration of MXenes to address current challenges in high-performance Li–Se batteries.
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- Award ID(s):
- 2400109
- PAR ID:
- 10618538
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 13
- Issue:
- 29
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 24038 to 24050
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Two-dimensional (2D) transition metal carbides, nitrides and carbonitrides, known as MXenes, are of interest as electrocatalysts. Tungsten-based MXenes are predicted to have low overpotentials in the hydrogen evolution reaction but their synthesis has proven difficult due to the calculated instability of their hypothetical MAX precursors. In this study, we present a theory-guided synthesis of a tungsten-based MXene, W2TiC2Tx, derived from a non-MAX nanolaminated ternary carbide (W,Ti)4C4−y precursor by the selective etching of one of the covalently bonded tungsten layers. Our results indicate the importance of tungsten and titanium ordering, the presence of vacancy defects in the metal layers, and the lack of oxygen impurities in the carbon layers for the successful selective etching of the precursor. We confirm the atomistic out-of-plane ordering of tungsten and titanium using computational and experimental characterizations. The tungsten-rich basal plane endows W2TiC2Tx MXene with a high electrocatalytic hydrogen evolution reaction performance (∼144 mV overpotential at 10 mA cm−2). This study reports a tungsten-based MXene synthesized from a covalently bonded non-MAX precursor, adding to the synthetic strategies for 2D materials.more » « less
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