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

Graphical Potassium titanate (K 2 Ti 8 O 17 ) nanobelts (KTN) are a unique support for Au and bimetallic AuRh nanoparticles showing strong enhancement of the catalytic reduction of NO with CO to N 2 .The KTN support facilitates the formation of surface nitrate, carbonate and isocyanide species, resulting in superior catalytic activity compared to corresponding TiO 2 -supported catalysts. The catalytic reduction of NO with CO was examined over monometallic Au and bimetallic AuRh nanoparticles supported on potassium titanate (K 2 Ti 8 O 17 ) nanobelts (KTN) and TiO 2 . The highly crystalline KTN, prepared from TiO 2 by a hydrothermal process using KOH, were several μm 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 TiO 2 -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 (−NO 3 − ), carbonate (−CO 3 2− ), 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 +CO 2 .