1. Standard SCR (SSCR) Reaction Mechanism

• Active Sites: In SSCR, the dynamic dinuclear Cu⁺ species are the primary active sites. These Cu⁺ species can cycle between CuI and CuII oxidation states during the reaction, facilitating the conversion of NO and NH₃ into N₂ and H₂O.
• Redox Cycle: The redox cycle of Cu ions is crucial for SSCR. CuII is first reduced to CuI, which then reacts with NO and NH₃ to form intermediate products. Subsequently, CuI is oxidized back to CuII, completing the catalytic cycle.
• Reaction Intermediates: Studies suggest the formation of intermediates such as [CuI(NH₃)₂]⁺-O₂-[CuI(NH₃)₂]⁺ during SSCR. These intermediates help lower the activation energy of the reaction, thereby enhancing the reaction rate.
• Reaction Pathway: The SSCR reaction typically follows a Langmuir-Hinshelwood mechanism, where NO and NH₃ adsorb onto adjacent Cu active sites, react to form intermediate species, and then desorb as N₂ and H₂O.

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