Figure 6: (a) Evolution of salicylic acid concentration versus irradiation time, in solution containing M salicylic acid and 1.0 g/L of photocatalyst. UVA and Vis correspond to experiments performed under black light (360 nm) or filtered white light nm, respectively. (b) Evolution of DHB/salicylic ratio versus irradiation time for different catalysts and light (DHB: dihydroxybenzoic acid). TiO2 and N-TiO2 samples are prepared from precursors with N : Ti, 0 and N : Ti, 4 : 1, respectively, fired at 250°C, 3 h, and 500°C 1 min. Ramp: 10°C/min.