Two-Dimensional Vanadium Carbide Mxene for High Performance Chemiresistive Sensing

Abstract

Recently emerging materials for advancing gas sensor technology have potentialized versatile applications of a sensor in the society of safety, health, environmental protection and much more [1]. In accordance with significant progress of chemical and physical approaches, gas sensing materials are not limited to metal oxide but include various 2D nanostructures such as graphene and metal dichalcogenides, etc. [2, 3]. Of these, the rise of interest on newly discovered 2D transition metal carbides and/or carbonitrides (called MXenes) have recently shown their potential as sensing materials with their intriguing surface chemistry [4]. The first MXene material introducing in chemiresistive sensor is titanium carbide (Ti3C2Tx). Gas sensing capabilities of Ti3C2Tx MXene to detect various gases were demonstrated with their sensing mechanism [5], and now, further enhancement of its sensing performance is actively studied in many academic domains. Beginning with Ti3C2Tx, vast diversity in a combination of constituent elements and ordered structure in MXenes offers future possibilities to find out a new generation of sensing materials with their superior performance. In this study, 2D V2CTx gas sensors were firstly demonstrated in chemiresistive sensing. The sensor device was fabricated with single/few-layer 2D V2CTx on polyimide film after the selective etching process. This device measured both polar and non-polar chemical species such as hydrogen and methane at room temperature (23 °C) with an ultra-low limit of detection of 2 ppm and 25 ppm, respectively. 2D V2CTx gas sensors showed excellent gas sensing performance in terms of high response toward non-polar gases, which is originated from the surface oxygen functional groups on the surface of V2CTx nanoflakes. Compared to the sensing properties of Ti3C2Tx MXene [5], 2D V2CTx sensor showed higher selectivity and long-term stability. This comparative result suggests that the modification of ordered structure and constituent elements of MXenes play a pivot role in the interaction between analyte and MXenes leading to an extensive change in performance.