Shamim Siraj Ud Daula, Akter Taslima, Ananna Aditi Ahmed, Dash Bivas Kumar, Piya Afiya Akter
Department of Physics, Mawlana Bhashani Science and Technology University Tangail-1902 Dhaka Bangladesh
RSC Adv. 2025 Jun 18;15(26):20712-20722. doi: 10.1039/d5ra03541d. eCollection 2025 Jun 16.
In this study, we utilized density functional theory (DFT) with plane-wave calculations to investigate the gas-sensing capabilities of Mo- and Nb-based MXene nanosheets, including NbC, NbN, MoC, and MoN, as well as their heterostructures (NbMoC and NbMoN). We focused on assessing their effectiveness in detecting hazardous airborne gases, such as carbon monoxide (CO) and nitrogen monoxide (NO). The adsorption energy, charge transfer, work function, and electronic properties of the nanosheets and their heterostructures were examined to understand their adsorption behavior. Molecular dynamics and phonon calculations confirmed the thermal and mechanical stability of the nanosheets, with NbMoC being more stable than NbMoN. The band structures and density of states (DOS) indicate the metallic behavior of the nanosheets. CO and NO were adsorbed on NbC, with adsorption energies of -3.014 and -4.479 eV, respectively. A similar adsorption phenomenon was found for NbN. The adsorption of CO and NO on MoC occurred with adsorption energies of -2.456 and -2.984 eV, respectively. For heterostructures, gas molecules were adsorbed on the Mo and Nb sites of the nanosheets, with the Nb site being more favorable. Therefore, all MXenes exhibit strong sensitivity towards gas molecules, high interaction properties in the chemisorption range, short adsorption distance, and a significant amount of charge transfer to the gases. Although MoN interacts with gas molecules at exceptionally high adsorption energies, it is unsuitable for gas adsorption because of its high recovery time and high structural deformation upon adsorption. Therefore, all nanosheets, except for MoN, were considered promising candidates for detecting CO and NO gas molecules.
在本研究中，我们利用密度泛函理论（DFT）结合平面波计算，研究了基于钼（Mo）和铌（Nb）的MXene纳米片（包括NbC、NbN、MoC和MoN）及其异质结构（NbMoC和NbMoN）的气敏性能。我们着重评估它们在检测有害空气传播气体（如一氧化碳（CO）和一氧化氮（NO））方面的有效性。研究了纳米片及其异质结构的吸附能、电荷转移、功函数和电子性质，以了解它们的吸附行为。分子动力学和声子计算证实了纳米片的热稳定性和机械稳定性，其中NbMoC比NbMoN更稳定。能带结构和态密度（DOS）表明了纳米片的金属行为。CO和NO吸附在NbC上，吸附能分别为-3.014和-4.479 eV。在NbN上也发现了类似的吸附现象。CO和NO吸附在MoC上的吸附能分别为-2.456和-2.984 eV。对于异质结构，气体分子吸附在纳米片的Mo和Nb位点上，其中Nb位点更有利于吸附。因此，所有MXene对气体分子都表现出很强的敏感性、在化学吸附范围内具有高相互作用特性、吸附距离短以及向气体大量电荷转移。尽管MoN在极高的吸附能下与气体分子相互作用，但由于其高恢复时间和吸附时的高结构变形，它不适合用于气体吸附。因此，除MoN外，所有纳米片都被认为是检测CO和NO气体分子的有前途的候选材料。
