Study on Adsorption Characteristics and Sensing Performance of Zr-MOF-808@GO for SF6 Discharge Decomposition Gas

Sulfur hexafluoride (SF ₆ ) gas-insulated switchgear (GIS) is widely used in electrical power engineering. The decomposition products of SF ₆ have attracted significant attention as key indicators for assessing the operational safety of GIS. Consequently, developing sensing materials capable of detecting SF ₆ decomposition products at or near room temperature has become a significant research objective in this field. Resistive chemical sensors are commonly employed as research tools in gas detection studies and have been applied to the development of such sensing materials. Zr-MOF-808, a metal–organic framework known for its excellent gas adsorption properties, is widely used in gas storage applications. However, its practical application in chemical sensing is limited by its high initial electrical resistance and excessive gas response sensitivity. In this study, a Zr-MOF-808@GO composite was synthesized by coating Zr-MOF-808 with graphene oxide (GO). The introduction of GO, which possesses a large specific surface area and excellent electrical conductivity, serves three main purposes: (1) it mitigates the adverse effect of the high intrinsic resistivity of Zr-MOF-808 on the detection accuracy of resistive sensors; (2) it partially blocks the porous structure of Zr-MOF-808, reducing effective gas–material contact; and (3) it occupies active adsorption sites through electron pair interactions between oxygen atoms in GO and zirconium in the MOF, thereby attenuating the adsorption capacity. This synergistic interaction passivates the gas adsorption effect of the MOF, bringing the resistive response into a more readily measurable range.Furthermore, due to differences in adsorption energy and electron transfer between Zr-MOF-808@GO and various gas molecules, the composite exhibits distinct rates of resistance increase, enabling the discriminative detection of SF6 decomposition gases. By adjusting the mass ratio of Zr-MOF-808 to GO, the sensing responses to major SF6 decomposition products were systematically investigated. The resistance response trends indicate that a mass ratio of 1:2 provides optimal differentiation among the four target gases (CF ₄  < SO ₂ F ₂  < H ₂ S < SO ₂ ). In addition, density functional theory (DFT) calculations were employed to elucidate the underlying adsorption mechanisms, revealing principles for selective gas detection.