Degradation of rhodamine B photocatalyzed by Eu-doped CdS nanowires illuminated by visible radiation

Abstract

CdS nanowires doped with different contents of Eu dopant were synthesized by solvothermal method. XRD, SEM, TEM and Raman analyses certified that the as-synthesized samples were hexagonal CdS uniform nanowires. The pure CdS nanowires were 1–3 ​μm long and 80 ​nm diameter with the 1st and 2nd order longitudinal phonon modes at 298 and 594 ​cm−1. The 3% Eu-doped CdS wires were 800 ​nm–2.5 ​μm long and 75 ​nm diameter with the 1st and 2nd order longitudinal phonon modes at 296 and 593 ​cm−1. CdS nanowires grew along the [001] direction due to the surface energy effect. The photocatalytic properties of CdS and Eu-doped CdS nanowires were investigated for the degradation of rhodamine B (RhB) illuminated by visible radiation. In this research, Eu dopant played the role in promoting the photocatalytic kinetics because Eu3+ ions act as an electron acceptor to promote charge separation and photocatalytic activity. Both ●OH and ●O2− were the main active radicals used to transform RhB molecules into CO2, H2O and other intermediates.