Photocatalytic hydrodenitrogenation of aromatic cyanides on TiO2 loaded with Pd nanoparticles

• Published in: Catalysis science & technology 2013-01, Vol.3 (7), p.1718-1724
• Main Authors: Sugano, Yoshitsune, Fujiwara, Keisuke, Shiraishi, Yasuhiro, Ichikawa, Satoshi, Hirai, Takayuki
• Format: Article
• Language: English
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/c3cy20748j

Photocatalytic hydrodenitrogenation of aromatic cyanides has been carried out on TiO 2 loaded with Pd nanoparticles (PdTiO 2 ) in the presence of ethanol as a hydrogen source. Photoirradiation of PdTiO 2 at > 300 nm in ethanol containing aromatic cyanides successfully produces the corresponding toluene derivatives and triethylamine with almost quantitative yields. Photoexcited PdTiO 2 catalysts promote oxidation of ethanol and reduction of protons, producing acetaldehyde and hydrogen atoms on the surface of Pd particles (HPd species). Aromatic cyanides undergo hydrodenitrogenation via consecutive reactions involving hydrogenation by the HPd species and condensation with aldehydes. The catalytic activity strongly depends on the amount of Pd loaded. The catalyst containing 2 wt% Pd, with a relatively low Schottky barrier height at the PdTiO 2 heterojunction and a large number of surface Pd atoms, exhibits the highest denitrogenation activity. TiO 2 loaded with Pd particles, when photoirradiated in ethanol at room temperature, successfully promotes hydrodenitrogenation of aromatic cyanides, producing toluenes and triethylamine with almost quantitative yields.