Experimental  parameters Experimental results Pseudo-first order model Experimental results Pseudo-first order model CR BP4B ADS / % PCD /% kapp /min-1 t1/2 /min R2/% ADS/% PCD/% kapp/min-1 t1/2/min R2 /% Band gap of catalyst  [Eg ] (eV) Zn O 10.50 95.02 0.041 16.906 88.1 3.89 97.24 0.026 26.456 95.6 Ti O2 13.47 93.34 0.045 15.40 98.5 28, 52 68.54 0.002 346.57 78.2 Ce O2 8.00 14.93 0.003 231.05 49.0 25, 59 47.19 0.033 20.94 70.7 Al2O3 4.21 7.91 0.001 693.15 88.7 13, 73 50.21 0.011 63.01 46.4 Fe2O3 5.15 4.72 0.001 693.15 34.0 1, 74 12.77 0.018 38.08 95.0 R2: Regression coefficient, ADS: Adsorption and PCD: Photocatalytic degradation

Table 5: Kinetic parameters of photocatalytic degradation of dyes in aqueous solution as a function of band gap of semiconductors. ([Catalyst]=0.5g/L (for CR) and 1g/L (for BP4B), [CR]=20mg/l, pH =8, T=298K,λmax=365 nm and I=90j/cm2).