Selective methane chemiresistive detection using MWCNTs array decorated by metal organic framework layer

Abstract

Methane as a main component of natural gas, but simultaneously an explosive compound with pronounced negative environmental impact. Therefore, methane should be detected with high precision and reliability. However, the inertness and non-polar nature of methane is limiting its simple detection (e.g., by a chemiresistive approach) living a gap in sensing solution. In this paper, we propose a selective chemiresistive methane sensor consisting of abundant carbon materials (multi-walled carbon nanotubes - MWCNTs) with a metal-organic framework (PCN-14). The sensor is based on decorating a non-ordered array of MWCNTs with PCN-14, which is known to have high selectivity towards methane. The methane molecules are selectively entrapped by PCN-14 pores, which significantly affect the resistance of created hybrid materials. As a result, we could detect methane under air pressure and at room temperature, with a negligible false response from other interfering gases or moisture (except hydrogen or ethane). Despite its extreme simplicity, our chemiresistive sensor does not require chemical reaction or material-destructive binding/oxidation of methane. Therefore, long operation time and sensor stability were expected and experimentally confirmed. Finally, the initial resistance of MWCNTs-PСN-14 hybrid materials was adjusted to be measurable by a portative multimeter range, which makes our approach very simple and technically undemanding.