CuO/ZnO Modified C4N Monolayer for SF6 Decomposition: Experimental Analysis and First-Principles Simulation

Sulfur hexafluoride (SF6) serves as an essential insulating and arc-extinguishing medium in power facilities, while it is an extremely potent greenhouse gas with an ultra-long atmospheric lifetime. To realize efficient medium-temperature harmless disposal of waste SF6, two-dimensional stable C4N monolayers were adopted as substrates to load ZnO and CuO nanoparticles for composite catalyst fabrication. XRD, TEM, and EDS characterizations confirmed the uniform dispersion of the metal oxides without destroying the C4N two-dimensional skeleton. Comparative experiments proved that an NH3 reducing atmosphere significantly accelerates SF6 decomposition. The 3:1 CuO-modified catalyst achieved a maximum SF6 conversion of 91%, and a CaO additive effectively restrained high-temperature sintering and irreversible HF halogen poisoning, boosting overall catalytic efficiency by approximately 30%. DFT adsorption simulations revealed totally different active centers: hollow sites dominate ZnO-C4N with broad adsorption capacity for SO2, SO2F2, and other fluorinated intermediates, whereas surface O sites of CuO-C4N exhibit exclusive strong chemisorption toward SO2. Combined with macroscopic kinetics and atomic-scale interfacial interaction rules, their distinct stepwise defluorination pathways were illustrated. This study offers solid experimental data and microscopic theoretical guidance for designing advanced C4N-based catalysts for waste SF6 abatement.