Photocatalytic oxidation of benzyl alcohol coupled with p-dinitrobenzene reduction over poly(o-phenylenediamine) nanowires-decorated Gd-TiO2 nanorods

Abstract

Simultaneous oxidation of benzyl alcohol (BA) and reduction of p-dinitrobenzene (p-DNB) over Gd-doped TiO2nanorods decorated with poly(o-phenylenediamine, PoPD) nanowires was reported in this work. The doping of TiO2 with Gd induced surface defects, i.e., oxygen vacancy (OV) and the Ti3+–on-Ti4+site, while incorporating PoPD highly enhanced the light absorption capability and electron conductivity of TiO2nanorods,as confirmed by UV–vis diffuse reflectance spectroscopy (DRS) and electrochemical measurements, respectively. BA was selectively oxidized by photogenerated h+to form benzaldehyde with a yield of 70.5% in water and 90.6% in acetonitrile solvent. Conversely, p-DNB was selectively reduced to p-nitroaniline (p-NA) with a yield of 89.1% in acetonitrile and to p-phenylenediamine (p-PDA) of 85.0% yield in water. This work demonstrates a vital strategy to utilize the full economic potential of photogenerated charge carriers and the decisive role of solvent for product selectivity in the course of selective organic transformations.