Potassium Titanate Nanobelts: A Unique Support for Au and AuRh Nanoparticles in the Catalytic Reduction of NO with CO

摘要

The catalytic reduction of NO with CO was examined over monometallic Au and bimetallic AuRh nanoparticles supported on potassium titanate (K2Ti8O17) nanobelts (KTN) and TiO2. The highly crystalline KTN, prepared from TiO2 by a hydrothermal process using KOH, were several mu m long and ca. 8 nm wide. Both Au and bimetallic AuRh catalysts showed a striking enhancement of the catalytic performance with KTN as support, compared to corresponding TiO2-supported catalysts. The reasons for this behavior could be traced back using in situ diffuse reflectance infrared Fourier transform spectroscopy in tandem with modulation excitation spectroscopy, which proved that the KTN support promotes the formation of surface nitrate (-NO3-), carbonate (-CO32-), and isocyanide (-NCO) species. In particular, the combination of KTN with bimetallic AuRh nanoparticles results in the facile formation of isocyanide, which is a pivotal intermediate for producing dinitrogen molecules via the reaction with NO; NCO(a)+NO(a)-> N-2+CO2.