Ag + and Cu 2+ doped CdS nanorods with tunable band structure and superior photocatalytic activity under sunlight

Abstract The influence of Ag+ and Cu2+ doping (1 to 10 mol%) on the optical, structural and photocatalytic properties of CdS-nanorods is systematically studied. Doping of metal ions slightly distorts the hexagonal-phase of CdS though they have a strong bonding interaction with S2−. The bandedge positions of CdS-nanorods are significantly shifted; 2.56 → 2.29 eV and 2.56 → 2.31 eV with gradual doping of Ag+ and Cu2+ ions. The catalytic-activity is studied by photooxidation of salicyladehyde and photoreduction of m-dinitrobenzene under sunlight. The activity is improved with doping, where AgxCd1-xS (x = 0.1) composite displayed the highest photooxidation of 0.5 mM salicylaldehyde ( > 90%) and photoreduction of 5 mM, m-DNB (89.6%) to m-NA (38%) and m-PDA (52%) as compared to pure CdS and CuxCd1−xS (x = 0.1) composite. It is found that doping in CdS results in narrowing of bandedge potentials and distortion in the crystal that leads to weakening of bonds to avail charge carriers for corresponding reactions.