Comparative Density Functional Theory Insights Into B 16 C 16 and Si 16 C 16 Nanocages for Sensing Oil‐Derived Fault Gases in Energy and Industrial Systems

Oil‐immersed electrical equipment, including power transformers and underground cables, generates fault‐related decomposition gases such as C 2 H 4 , CO, and H 2 S under abnormal operating conditions. Prompt and accurate detection of these toxic gases is critical for safe operations and system reliability. In this study, the adsorption and sensing behavior of these gases on boron carbide (B 16 C 16 ) and silicon carbide (Si 16 C 16 ) nanocages were investigated using density functional theory (DFT) at the B3LYP‐D3/6‐31G(d, p) level. Results show that gas adsorption is more effective on the BC nanocage than on SiC. The highest negative adsorption energies were recorded for C 2 H 4 and CO on BC, reaching −80.274 and −84.580 kcal, for the C 2 H 4 _C4_BC and CO_C6_BC systems, respectively. H 2 S adsorption on BC produced the lowest energy gaps of 1.867 and 1.914 eV in H 2 S_C6_BC and H 2 S_C4_BC, respectively, significantly enhancing electrical conductivity to 5.45 × 10 12 S/m and 5.40 × 10 12 S/m. BC‐based systems consistently yielded positive sensing responses, while SiC‐based systems showed mostly negative values. NCI and QTAIM analyses confirmed covalent and partially covalent interactions between the analytes and nanocages. These findings establish BC nanocages as superior candidates for detecting fault gases, offering theoretical guidance for next‐generation sensors in power transformer diagnostics, renewable energy safety monitoring, and industrial hazard detection.