Preparation And NO₂ Gas Sensing Performance Of Two-dimensional Tellurium

Air pollution is nowadays a big issue regarding the health of human beings.Among the toxic gases emitted in the atmosphere,NO₂ is the most serious one and a lot of countries or cities want to monitor its concentration so that it can take measures to reduce its content.Therefore,there is an urgent need to develop high-performance,low-power and low-cost NO₂ sensors.Since the successful synthesis of graphene,two-dimensional materials have provided broader research directions for new basic sciences and important technical applications.After graphene,other emerging 2D materials,such as phosphorene?single element 2D material?,MoS₂?transition-metal sulfides,TMDC?,and Ti₃C₂T_x?MXene?,have been used for gas sensing.Compared with traditional metal oxide gas sensors,two-dimensional materials have higher sensitivity,the possibility of operating at room temperature and low power consumption.However,existing studies have shown that graphene and MXene lack energy band gaps,transition metal dihalides?such as MoS₂?lack high sensitivity,and the poor air stability of phosphoene limits their further development.Against this background,a simple hydrothermal method was used to prepare a highly sensitive,fast response,and low detection limit room temperature NO₂ gas sensor material-a new emerging single element 2D material tellurene.The response time of the tellurene-based sensor at room temperature to 2.5 ppm is 14.5 s at 1 ppm,with completely recovering,and the response is 61%.Devices based on tellurene exhibit a detection limit of 20 ppb,and the baseline noise RMS as low as 0.2%.Density functional theory calculations show that the larger the adsorption energy and the more obvious changes in the electronic structure are the reasons for the high sensitivity and selectivity of tellurene for detecting NO₂.Most importantly,tellurene has excellent air stability,making it a promising candidate for the next generation of chemical sensors.