Novel Two-Dimensional MC2N4 (M = Cr, Mo, W) Monolayers for Overall Water Splitting with High Visible-Light Absorption. (15th July 2022)

• Record Type: Journal Article
• Authors: Ur Rehman, Sajid; Tariq, Zeeshan; Butt, Faheem K.; Zhang, Xiaoming; Ul Haq, Bakhtiar; Li, Chuanbo
• Is Part Of: Solar energy. Volume 241(2022)
• Page Start: 416
• Page End: 427
• Publication Date: 2022-07-15
• Subjects: Novel 2D materials -- Highly Stability -- Excellent Photocatalysts -- Visible light absorption; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2022.06.014
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: Research highlights: MC2 N4 (M = Cr, Mo, W) monolayers show excellent mechanical and dynamical stabilities. CrC2 N4 exhibits direct bandgap along with strong visible absorption. All monolayers have suitable band edges for overall photocatalytic water splitting. CrC2 N4 performs better overall water splitting under compressive strain. Abstract: Recently, the synthesis of 2D MoSi2 N4 (Science; 2020;369; 670) proclaimed the dawn of a new family of 2D MA2 Z4 materials. In this regard, through first-principles calculations, we proposed novel MC2 N4 (M = Cr, Mo, W) monolayers with outstanding stability, which indicates a high possibility for experimental synthesis. The current study reveals that CrC2 N4 (2.67 eV) is a direct bandgap semiconductor, whereas MoC2 N4 (2.80 eV) and WC2 N4 (2.84 eV) are indirect bandgap semiconductors, employing the HSE06 hybrid functional. All monolayers yield suitable band edge positions, making them ideal for photocatalytic water splitting and optoelectronics applications. Interestingly, the CrC2 N4 monolayer has strong optical absorption in the visible spectrum. In contrast to MoC2 N4 (WC2 N4 ) monolayer, the Young's and layered moduli of the CrC2 N4 monolayer are significantly high, 675 Nm −1 and 405 Nm −1, respectively. In contrast MC2 N4 (M = Mo, W) monolayers exhibited a highly anisotropic nature compared to CrC2 N4 . Moreover, strain (+6% to −6%) has played an exciting role in modulating the bandgap and band alignment positions of the MC2 N4 (M = Cr, Mo, W) monolayers. Interestingly, compressive strain is more beneficial for the CrC2 N4 monolayer to perform photocatalytic water splitting under strong visible light. This work highlights the CrC2 N4 monolayer as a novel 2D semiconductor with high stability and excellent photocatalytic properties.