Zhang Youwei, Chen Xingzhu, Augustine Kwaw Blankson, Zhang Peng, Jiang Jizhou, Wu Qi, Li Neng
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, Hubei, China.
Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, China.
ACS Omega. 2021 Mar 24;6(13):9013-9019. doi: 10.1021/acsomega.1c00036. eCollection 2021 Apr 6.
The two dimensional (2D)-layered transition-metal carbides and nitrides (MXene) have been proved to be an excellent solid lubricant owing to their high mechanical strength, low shearing strength, and self-lubricating properties. However, the interfacial friction behavior between Ti C ( = 1, 2) MXene and its heterogeneous system is not thoroughly exploited yet. Here, four types of van der Waals structures (TiCO@TiCO, TiCO@TiCO MoS@MoS, and TiCO@MoS) have been investigated by density functional theory (DFT) calculations. The results exhibit that TiCO@MoS possesses the lowest sliding energy barrier around 0.015 eV/oxygen(O) atom compared with the other three constructed models. Therefore, this work mainly focuses on the inner relation of TiCO@MoS interlayer friction behaviors and its attributing factors, including normal force and charge density. The DFT analysis shows that the roughness of the potential energy corrugated plane is positively correlated with normal force and predicted the ultralow friction coefficient (μ) at 0.09 when sliding along the minimum energy potential route. Moreover, friction coefficient fluctuates at the normal force less than 10 nN determined by the combined effect of interfacial charge interlock and redistribution. This work reveals the intrinsic connection between the friction and charge interaction at heterogeneous interfaces.
二维（2D）层状过渡金属碳化物和氮化物（MXene）因其高机械强度、低剪切强度和自润滑性能，已被证明是一种优异的固体润滑剂。然而，TiₙCₘ（n = 1, 2）MXene与其异质体系之间的界面摩擦行为尚未得到充分研究。在此，通过密度泛函理论（DFT）计算研究了四种类型的范德华结构（TiCO@TiCO、TiCO@TiCO₂、MoS₂@MoS₂和TiCO@MoS₂）。结果表明，与其他三种构建模型相比，TiCO@MoS₂具有最低的滑动能垒，约为0.015 eV/氧（O）原子。因此，这项工作主要关注TiCO@MoS₂层间摩擦行为的内在关系及其影响因素，包括法向力和电荷密度。DFT分析表明，势能波纹平面的粗糙度与法向力呈正相关，并预测沿最小能量势路径滑动时的超低摩擦系数（μ）为0.09。此外，在小于10 nN的法向力下，摩擦系数因界面电荷互锁和重新分布的综合作用而波动。这项工作揭示了异质界面处摩擦与电荷相互作用之间的内在联系。
