Mechanism by which Tungsten Oxide Promotes the Activity of Supported V 2 O 5 /TiO 2 Catalysts for NO X Abatement: Structural Effects Revealed by 51 V MAS NMR Spectroscopy

By Nicholas R. Jaegers, Jun‐Kun Lai, Yang He, E. Walter, D. Dixon, Monica Vasiliu, Ying Chen, Chongmin Wang, Mary Y. Hu, K. Mueller and 3 more. Angewandte Chemie, 2019

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The selective catalytic reduction (SCR) of NOx with NH3 to N2 with supported V2 O5 (-WO3 )/TiO2 catalysts is an industrial technology used to mitigate toxic emissions. Long-standing uncertainties in the molecular structures of surface vanadia are clarified, whereby progressive addition of vanadia to TiO2 forms oligomeric vanadia structures and reveals a proportional relationship of SCR reaction rate to [surface VOx concentration]2 , implying a 2-site mechanism. Unreactive surface tungsta (WO3 ) also promote the formation of oligomeric vanadia (V2 O5 ) sites, showing that promoter incorporation enhances the SCR reaction by a structural effect generating adjacent surface sites and not from electronic effects as previously proposed. The findings outline a method to assess structural effects of promoter incorporation on catalysts and reveal both the dual-site requirement for the SCR reaction and the important structural promotional effect that tungsten oxide offers for the SCR reaction by V2 O5 /TiO2 catalysts.

Subfields: Catalysis, Materials Chemistry, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/14c1f8264533dc8505125dcf4bf46db4205ee0d2