Using first-principles theory, we investigated the most stable configuration for the Rh dopant on a MoSe₂ monolayer, and the interaction of the Rh-doped MoSe₂ (Rh-MoSe₂) monolayer with four toxic gases (CO, NO, NO₂ and SO₂) to exploit the potential application of the Rh-MoS₂ monolayer as a gas sensor or adsorbent.

A gas sensor is used to detect SF₆ decomposed gases, which are related to insulation faults, to accurately assess the insulated status of electrical equipment. Graphene films (GrF) modified with Au nanoparticles are used as an adsorbent for the detection of H₂S and SOF₂, which are two characteristic products of SF₆ decomposed gases. Sensing experiments are conducted at room temperature. Results demonstrate that Au‐modified GrF yields opposite responses to the tested gases and is thus considered a promising material for developing H₂S‐ and SOF₂‐selective sensors. The first‐principles approach is applied to simulate the interaction between the gases and Au‐modified GrF systems and to interpret experimental data. The observed opposite resistance responses can be attributed to the charge‐transfer differences related to the interfacial interaction between the gases and systems. The density of states and Mulliken population analysis results confirm the apparent charge transfer in Au‐modified GrF chemisorption, whereas the van der Waals effect dominates the pristine graphene adsorption systems. Calculation results can also explicate the significant SOF₂ responses on Au‐modified GrF. This work is important in graphene modulation and device design for selective detection.

Partial discharge (PD) is usually aroused before the failure of gas insulated switchgear (GIS) caused by defects, which results in the decomposition of the SF₆ used as insulating gas. Analyzing SF₆ decomposition products can aid in PD detection. Before recognizing PD types by analyzing SF6 decomposition products, the decomposition characteristics of SF₆ under different types of PD should be investigated first. In this paper, a gas chamber and four typical types of artificial defects were designed to simulate the SF₆ decomposition phenomenon under PD in GIS. A gas chromatography system was established to detect SF₆ decomposition products. By selecting the chromatographic column, SF₆ decomposition products were successfully separated and their concentrations were measured. Numerous SF₆ decomposition experiments under four kinds of PD generated by four kinds of artificial defects were carried out and the SF6 decomposition products produced by each experiment were detected. The decomposition characteristics of SF₆ under the four defects were different in terms of decomposition amount, generation rate, and concentration ratio, among others. It is feasible to recognize the type of PD by analyzing SF₆ decomposition products.

In recent years, many novel sensing nanomaterials were explored experimentally and theoretically as chemical gas sensors to detect sulphur hexafluoride (SF ₆ ) decomposed species with rapid response, high sensitivity and selectivity, as well as low cost, in order to estimate and guarantee the operation status of SF ₆ insulation devices. However, there has been no systemic review yet to comprehensively understand their sensing mechanism and conclude their sensing application. Such kinds of nanomaterials include traditional carbon‐based materials such as carbon nanotube and graphene, metal oxides such as SnO ₂ , ZnO and TiO ₂ , transition metal dichalcogenides such as MoS ₂ monolayer and MoTe ₂ monolayer as well as graphene‐like InN monolayer. A systemic review would be significant to give a profound insight into the exploration of nanomaterial‐based chemical gas sensors in the field of electrical engineering and to help youth scholars first stepping in this field rapidly master the progress inside. Thus, the authors attempt to complete this review here. They are hopeful that this review could provide some guidance to fulfil such purpose in the near future, and it would be full of perspective to explore more novel nanomaterials as defect indicators in SF ₆ insulated devices. Furthermore, it is their hope that this review could broaden the sensing application of admirable nanomaterials in many fields such as environmental monitoring and pollutant scavenging.