Catalytic decomposition of NO₂ over a copper-decorated metal–organic framework by non-thermal plasma

Efficient catalytic conversion of NO₂ to non-harmful species remains an important target for research. State-of-the-art deNO_x processes are based upon ammonia (NH₃)-assisted selective catalytic reduction (NH₃-SCR) over Cu-exchanged zeolites at elevated temperatures. Here, we describe a highly efficient non-thermal plasma (NTP) deNO_x process catalyzed by a Cu-embedded metal-organic framework, Cu/MFM-300(Al), at room temperature. Under NTP activation at 25°C, Cu/MFM-300(Al) enables direct decomposition of NO₂ into N₂, NO, N₂O, and O₂ without the use of NH₃ or other reducing agents. NO₂ conversion of 96% with a N₂ selectivity of 82% at a turnover frequency of 2.9 h⁻¹ is achieved, comparable to leading NH₃-SCR catalysts that use NH₃ operating at 250°C–550°C. The mechanism for the rate-determining step (NO→N₂) is elucidated by in operando diffuse reflectance infrared Fourier transform spectroscopy, and electron paramagnetic resonance spectroscopy confirms the formation of Cu²⁺⋯NO nitrosylic adducts on Cu/MFM-300(Al), which facilitates NO dissociation and results in the notable N₂ selectivity. Nitrogen oxide causes significant effects on the environment and human health. Xu et al. report, to the best of their knowledge, the first example of nonthermal plasma-activated direct decomposition of NO₂ over stable and efficient metal-organic framework-based catalysts at room temperature and without the use of NH₃ or other reducing agents.