Purpose/Aim
SF₆ is widely used in gas- insulated equipments for its non-toxicity, great insulation strength and outstanding arc-distinguishing performance. However, it is inevitable to encounter operational faults like partial over thermal and discharge, and part of SF₆ may decompose into sulfur-containing components, in which H₂S is a vital marker to effectively reflect the severity of insulation faults inside gas- insulated equipments. Thus, fast and accurate detection of H₂S is of vital significance for judging the type and severity of internal faults in equipments and monitoring insulation states of the equipment. For this reason, we propose a chemical method using Ag-modified Ti₃C₂T_x MXene to detect low concentration H₂S.
Experimental/Modeling methods
Ti₃C₂T_x MXene was prepared by LiF/HCl etching and Ag NPs was introduced by self-reduction of Ag⁺ in Ti₃C₂T_x MXene suspension. Gas sensor was fabricated by drop-coating on interdigital electrodes and gas sensing performance was tested by electrochemical workstation(CHI600E).
Results/discussion
Ag-modified Ti₃C₂T_x MXene achieves a response of -5.98% to 0.1 ppm H₂S and -19.77% to 10 ppm H₂S, enhanced 6 and 12 times than those of pristine Ti₃C₂T_x MXene. Ag-modified Ti₃C₂T_x MXene exhbits fast response and recovery time of about 100s/5s and excellent response characteristic in dynamic sensing detection.
Conclusions
We reported a method of synthesizing Ag-modified Ti₃C₂T_x MXene for detecting low concentration H₂S, significantly promoting response value and detection speed. Meanwhile, this study further explained the sensing mechanism in both experiment and theory, explaining that the introduction of Ag NPs and the increasing specific surface area are main reasons for gas-sensing promotion.
 

H2S,gas sensing,Ti3C2Tx,Ag doping