Heteroatom decorated C2N monolayer for gas-sensing application: Insight from first-principles.

Development of novel gas-sensing materials is essential to high-performance gas sensors for monitoring target gases in industrial production and environmental protection. Herein, we investigate two types of the heteroatom-decorated C2N monolayer, denoted as M@C2N (M = Mn and Ni) and B-C2N, for their gas-sensing functionality toward seven small gaseous molecules (H2, O2, N2, CO, CO2, NH3, and H2O). The key gas-sensing characteristics concerning chemiresistive (CR) and field-effect transistor (FET) gas sensing have been thoroughly explored. The results show that Mn@C2N and Ni@C2N can work as either CR or FET gas-sensing materials for detecting H2, O2, N2, CO, CO2, NH3, and H2O, whereas B-C2N can work as a disposable gas sensor for O2, H2O, and NH3. Mn@C2N and Ni@C2N are the most selective toward O2 and NH3, followed by CO and H2O in an oxygen- and ammonia-free environment, while B-C2N is the most selective toward H2O and NH3. More importantly, the adsorption strength of target molecule plays a critical role in gas-sensing mechanism as well as selectivity, recovery time, and sensitivity. This study offers theoretical perspectives on 2D hybrid carbon-based nanomaterials for efficient gas sensing.