Adsorption and sensing of dissolved gases in transformer oil by Ni-modified h-BN monolayer: A DFT study

The use of high-sensitivity gas sensors to detect dissolved gases in the oil is a repeatable and effective method to assess the operating condition of a transformer. Based on DFT calculations, analysis of the adsorption and sensing performance of Ni-doped h-BN monolayer on three major dissolved gases H2, CH4 and C2H4 in transformer oil were performed. The gas adsorption and sensing mechanisms were explored using the geometry optimization, adsorption energy, band structure, charge transfer, deformation charge density, molecular orbitals, density of states and recovery time. The results show that the doped modified Ni-BN has the sensing ability for all three gases. The adsorption energies for H2, CH4 and C2H4 are -1.418, -1.300 and -2.633 eV, respectively. In particular, it has the best adsorption capacity for C2H4, but is difficult desorb with a desorption time of 4.39 x 1014s at 498 K; the adsorption performance for CH4 is excellent, while the desorption time is 14.10 s when the temperature is 498 K. In conclusion, this work provides a reference for the selection of materials for the detection of dissolved gases in transformer oil and provides theoretical guidance for the development of Ni-BN gas-sensitive sensors.