A Single Copper–Vanadium Oxide Cluster Cu 3 VO 3 – Reduces Four NO Molecules with the Accomplishment of a Catalytic Cycle by CO

Catalytic removal of NO and CO from exhaust is imperative due to their detrimental effects on the environment and human health, while the nature of active sites driving efficient NO reduction remains elusive. Herein, in combination with state-of-the-art mass spectrometry and quantum-chemical calculations, we demonstrate that copper–vanadium oxide clusters Cu 3 VO 3–5 – can catalytically reduce four NO molecules into N 2 O by CO. This finding represents a significant improvement in cluster science in which two NO molecules are commonly involved in the catalysis. The key to driving this substantially improved NO reduction efficiency by Cu 3 VO 3 – lies in the unique structure of intermediate product Cu 3 VO 4 –, which electronically resembles Cu 3 VO 3 – with a single unpaired electron localized in the V 3d orbital. This electronic configuration is vital to selectively reducing NO into N 2 O. Cu 3 VO 3 – can be regenerated through CO oxidation by product Cu 3 VO 5 – to complete the catalysis. The fundamental reasons behind this intriguing NO reduction behavior were further rationalized by theoretical calculations.