Room Temperature and Humidity Resistant NH3 Detection Based on a Composite of Hydrophobic CNTs with Sulfur Nanosheets

Abstract

A composite of sulfur nanosheets (S-NSs) with hydrophobic carbon nanotubes (H-CNTs) was designed, and a chemiresistive gas sensor based on this composite material was constructed for breath analysis of NH₃ detection at room temperature. Taking advantage of the capillary condensation of CNTs, the hydrophobic effect of hexadecyltrimethoxysilane (HDTMS), and the high sensitivity of S-NSs to NH₃ detection, the constructed sensor showed an improved humidity-resistant capacity and is capable of detecting breath-relevant NH₃ concentrations down to ppb level under high humidity. The fabricated gas sensor exhibited fast response/recovery (18/26 s) and good stability. Online monitoring for exhaled breath analysis shows good recovery with a stable baseline, providing a potential practical application. The research also facilitates the development of commercial low-cost breath analysis sensors.