NEST Lab, Department of Chemistry, College of Science, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
Shenzhen Key Laboratory of Advanced Thin Films and Applications, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
ACS Sens. 2024 Apr 26;9(4):1906-1915. doi: 10.1021/acssensors.3c02659. Epub 2024 Apr 2.
As a carcinogenic and highly neurotoxic hazardous gas, benzene vapor is particularly difficult to be distinguished in BTEX (benzene, toluene, ethylbenzene, xylene) atmosphere and be detected in low concentrations due to its chemical inertness. Herein, we develop a depth-related pore structure in Cu-TCPP-Cu to thermodynamically and kinetically enhance the adsorption of benzene vapor and realize the detection of ultralow-temperature benzene gas. We find that the in-plane π electronic nature and proper pore sizes in Cu-TCPP-Cu can selectively induce the adsorption and diffusion of BTEX. Interestingly, the theoretical calculations (including density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations) exhibit that benzene molecules are preferred to adsorb and array as a consecutive arrangement mode in the Cu-TCPP-Cu pore, while the TEX (toluene, ethylbenzene, xylene) dominate the jumping arrangement model. The differences in distribution behaviors can allow adsorption and diffusion of more benzene molecules within limited room. Furthermore, the optimal pore-depth range (60-65 nm) of Cu-TCPP-Cu allows more exposure of active sites and hinders the gas-blocking process. The optimized sensor exhibits ultrahigh sensitivity to benzene vapor (155 Hz/μg@1 ppm), fast response time (less than 10 s), extremely low limit of detection (65 ppb), and excellent selectivity (83%). Our research thus provides a fundamental understanding to design and optimize two-dimensional metal-organic framework (MOF)-based gas sensors.
苯蒸气是一种致癌和高度神经毒性的危险气体，由于其化学惰性，在 BTEX（苯、甲苯、乙苯、二甲苯）环境中特别难以区分，并且在低浓度下难以检测。在此，我们在 Cu-TCPP-Cu 中开发了一种与深度相关的孔结构，以热力学和动力学增强苯蒸气的吸附，并实现超低温度苯气体的检测。我们发现，Cu-TCPP-Cu 的面内π电子性质和适当的孔径可以选择性地诱导 BTEX 的吸附和扩散。有趣的是，理论计算（包括密度泛函理论（DFT）和巨正则蒙特卡罗（GCMC）模拟）表明，苯分子优先在 Cu-TCPP-Cu 孔中以连续排列的方式吸附和排列，而 TEX（甲苯、乙苯、二甲苯）则占据跳跃排列的模式。分布行为的差异可以允许在有限的空间内吸附和扩散更多的苯分子。此外，Cu-TCPP-Cu 的最佳孔深范围（60-65nm）允许更多的活性位点暴露，并阻碍气体堵塞过程。优化后的传感器对苯蒸气具有超高的灵敏度（155Hz/μg@1ppm）、快速的响应时间（小于 10s）、极低的检测限（65ppb）和出色的选择性（83%）。因此，我们的研究为设计和优化二维金属有机骨架（MOF）基气体传感器提供了基本的理解。
