Visible light-induced photodegradation of rhodamine dyes over BiOCl, and the vital importance of the frontier orbital energy of the dye molecules in the reaction kinetics Kai Shen • M. A. Gondal • A. A. Al-Saadi • Liye Li • Xiaofeng Chang • Qingyu Xu Received: 22 April 2013 / Accepted: 29 August 2013 / Published online: 26 September 2013 Ó Springer Science+Business Media Dordrecht 2013 Abstract The interfacial adsorption process and the white-light-induced photo- sensitized degradation of different rhodamine dyes (rhodamine B, rhodamine 6G, and rhodamine 101) on the wide-band-gap semiconductor BiOCl have been investigated. Adsorption of all the rhodamine molecules on BiOCl is an exothermic process and the saturated adsorption capacities were best deduced by Langmuir model fitting. By using quantum chemical calculations (Gaussian 03 software), the relationship between the frontier orbital energy of the dye molecules and the rate of photodegradation was also established. The calculated absolute value of E LUMO was found to increase in the order Rh 101 \ Rh 6G \ RhB, which was similar to the trend of photodegradation reaction kinetics rate fitted by use of the pseudo-zero- order kinetics model. Keywords BiOCl  Adsorption  Photosensitized degradation  Rhodamine B  Rhodamine 6G  Rhodamine 101  Frontier molecular orbitals  Gaussian 03 program K. Shen  L. Li  X. Chang College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China M. A. Gondal (&)  X. Chang Laser Research Group, Physics Department and Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia e-mail: magondal@kfupm.edu.sa A. A. Al-Saadi Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia Q. Xu Department of Physics, Southeast University, Nanjing 211189, China 123 Res Chem Intermed (2015) 41:2753–2766 DOI 10.1007/s11164-013-1384-9