Investigation on the transport mechanism of gas molecules in porous graphene membranes

IF 3.8 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Vacuum Pub Date : 2025-05-08 DOI:10.1016/j.vacuum.2025.114389

Jun Zhang, Chenhui Liu, Rui Huang, Xudi Wang, Qing Cao

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引用次数: 0

Abstract

Porous Graphene Membranes (PGM) show great promise for ultra-sensitive gas leak detection, gas separation, and filtration. Unlike traditional micro/nanochannels, PGM contains nanopores with single-atom thickness. Gas transport in PGM combines surface diffusion (SD) and direct transport (DT) under atomic-scale confinement. Classical rarefied gas theories cannot explain these processes. This study uses an extremely low flow setup to measure PGM's gas transport properties. Molecular dynamics simulations analyze DT and SD mechanisms. The effects of nanopore diameter, pressure, temperature, and gas species on the ratio of total flux to DT flux (Ratio-T/DT) are systematically investigated. Results reveal that PGM's gas transport deviates from Graham's law. As the nanopore diameter varies from 0.6 to 9 nm, Ratio-T/DT exhibits three distinct regimes: dominated by (1) two-dimensional motion and energy barrier (0.6–0.8 nm), (2) steric effect (0.8–2 nm), and (3) direct transport (>2 nm). This study reveals the gas transport mechanisms within PGM and provides insights for expanding its applications.

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多孔石墨烯膜中气体分子输运机理的研究

多孔石墨烯膜（PGM）在超灵敏气体泄漏检测、气体分离和过滤方面显示出巨大的前景。与传统的微纳米通道不同，PGM含有单原子厚度的纳米孔。PGM中的气体输运结合了原子尺度约束下的表面扩散和直接输运。经典的稀薄气体理论无法解释这些过程。本研究使用极低流量装置来测量PGM的气体输运特性。分子动力学模拟分析了DT和SD的机理。系统研究了纳米孔径、压力、温度和气体种类对总通量与DT通量之比（ratio - t /DT）的影响。结果表明，PGM气体输运偏离格雷厄姆定律。当纳米孔直径在0.6 ~ 9 nm范围内变化时，Ratio-T/DT表现出三种不同的机制：由(1)二维运动和能量势垒（0.6 ~ 0.8 nm）、(2)位阻效应（0.8 ~ 2 nm）和(3)直接输运（>2 nm）主导。该研究揭示了PGM内部的气体输运机制，为扩大PGM的应用提供了见解。

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来源期刊

Vacuum 工程技术-材料科学：综合

CiteScore

6.80

自引率

17.50%

发文量

审稿时长

34 days

期刊介绍： Vacuum is an international rapid publications journal with a focus on short communication. All papers are peer-reviewed, with the review process for short communication geared towards very fast turnaround times. The journal also published full research papers, thematic issues and selected papers from leading conferences. A report in Vacuum should represent a major advance in an area that involves a controlled environment at pressures of one atmosphere or below. The scope of the journal includes: 1. Vacuum; original developments in vacuum pumping and instrumentation, vacuum measurement, vacuum gas dynamics, gas-surface interactions, surface treatment for UHV applications and low outgassing, vacuum melting, sintering, and vacuum metrology. Technology and solutions for large-scale facilities (e.g., particle accelerators and fusion devices). New instrumentation ( e.g., detectors and electron microscopes). 2. Plasma science; advances in PVD, CVD, plasma-assisted CVD, ion sources, deposition processes and analysis. 3. Surface science; surface engineering, surface chemistry, surface analysis, crystal growth, ion-surface interactions and etching, nanometer-scale processing, surface modification. 4. Materials science; novel functional or structural materials. Metals, ceramics, and polymers. Experiments, simulations, and modelling for understanding structure-property relationships. Thin films and coatings. Nanostructures and ion implantation.