SF6 decomposed gas sensing performance of van der Waals layered cobalt oxyhydroxide: insights from a computational study.

The detection of SF6 decomposition products plays a significant part in identifying and assessing the electric discharge faults in SF6 insulation equipment. We performed dispersion corrected density functional theory calculations to study the adsorption performance of CoOOH upon SO2, SF4, SOF2, CF4, and SO2F2 toxic gases, to investigate their potential application as a gas sensor. The results clearly show a weak force between the CoOOH sheet, and the molecular gas with moderate adsorption strength enhances the desorption processes. According to Löwdin charge population analysis, electrons transfer from the molecular gas to the CoOOH surface, where the molecular gas behaves like an electron donor. The lower bandgap energy of the adsorption systems compared with pristine CoOOH significantly increases its electrical conductivity and gas sensing performance. The higher charge transfer and adsorption energy of the SOF2 adsorption system compared with the other four molecular gas is due to orbital hybridization around the Fermi energy. The theoretical computed adsorption energy with ultrahigh sensitivity and fast recovery time suggests that SF6 decomposed gases reusability is achieved with CoOOH as a resistance-type gas sensor.