Table 2 First order rate constants (k′ × 105, s−1) Cr(VI) to Cr(III) ions photoreduction in the presence of TiO2 and Mn+/TiO2 (M–Co, Ni, Mn, Cu) films with different dopant concentrations
| Sample | Concentration of dopant ions | ||||
|---|---|---|---|---|---|
| 0% | 1% | 3% | 5% | 7% | |
| First order rate constants (k′ × 105, s−1) | |||||
| Co/TiO2 | 3.3 | 4.4 | 4.1 | 4.4 | 3.8 |
| Ni/TiO2 | 4.6 | 4.7 | 5.2 | 3.8 | |
| Mn/TiO2 | 4.5 | 4.2 | 3.5 | 3.6 | |
| Cu/TiO2 | 5.8 | 6.3 | 6.7 | 5.8 | |