Pyridine-Covalent Triazine Framework (py-CTF) as a Metal-Free Catalyst for Effective Toluene Abatement in Post-Plasma Catalytic Systems

In this study, we explore, for the first time, the use of a new pyridine-covalent triazine framework (py-CTF), containing both nitrogen and oxygen, as a metal-free catalyst in a post-plasma catalytic (PPC) system for abatement of toluene, a common volatile organic compound (VOC). The PPC system was evaluated under varying specific energy densities (SEDs) from 100 to 400 J/L and catalyst temperatures ranging from room temperature to 200 °C. Our findings reveal that combining py-CTF with non-thermal plasma significantly enhanced toluene removal efficiency compared to both plasma alone and catalyst alone systems. A remarkable toluene removal efficiency of 97.2% and CO_x (CO + CO₂) selectivity of 67.1% were achieved in the PPC system at an optimal catalyst temperature of 150 °C and an SED of 400 J/L, with minimized ozone production. In contrast, the plasma alone showed a removal efficiency of 54.8% and CO_x selectivity of 21.6% at the same SED, while the catalyst-alone reached 31.1% removal efficiency and 50.4% CO_x selectivity at the higher temperature of 400 °C. Notably, the energy yield (EY) improved from 4.1 g/kWh in plasma alone to 14.0 g/kWh in PPC at an SED of 100 J/L. Moreover, the py-CTF catalyst demonstrated excellent long-term stability, maintaining high efficiency and selectivity over extended operation times. Catalyst characterization before and after plasma treatment demonstrated minimal changes in physicochemical properties, confirming its durability. This study thus highlights the potential of py-CTF as a sustainable alternative to metal-based catalysts in plasma-catalytic VOC abatement.