Photocatalytic decomposition of phenol over N–TiO₂–SiO₂ catalyst under natural sunlight

Figures & data

Figure 1. Schematic diagram of TiO₂–SiO₂ mixed oxide preparation.

Figure 2. FE-SEM images of different catalysts. (a) TiO₂; (b) TiO₂–SiO₂ and (c) N–TiO₂–SiO₂.

Figure 3. (A) XRD patterns of N–TiO₂–SiO₂ calcined at different temperatures: (a) 350°C, (b) 400°C, (c) 450°C, (d) 500°C, (e) 550°C, (f) 600°C, (g) 700°C, (h) 900°C and (j) TiO₂ (P25-Degussa); (B) XRD patterns of different catalyst: (a) N–TiO₂–SiO₂–550, (b) TiO₂–SiO₂–550, (c) TiO₂–550 and (d) TiO₂ (P25-Degussa).

Table 1. BET specific surface areas of different catalysts.

Catalyst	TiO2 : SiO2 weight ratio	S BET (m^2 g^−1)
TiO2 (P25)	100 : 0	53.1
TiO2	100 : 0	82.7
TiO2–SiO2	95 : 5	143.5
N–TiO2–SiO2-350	95 : 5	198.7
N–TiO2-SiO2-400	95 : 5	229.8
N–TiO2-SiO2-450	95 : 5	124.4
N–TiO2-SiO2-500	95 : 5	145.7
N–TiO2-SiO2-550	95 : 5	165.7
N–TiO2-SiO2-600	95 : 5	133.2
N–TiO2-SiO2-700	95 : 5	130.4
N–TiO2-SiO2-900	95 : 5	56.4

Figure 4. UV-vis DRS of N–TiO₂–SiO₂ mixed oxide calcined at different temperatures.

Table 2. Phenol removal efficiency of different catalysts under UVA irradiation.

Catalysts	Phenol removal efficiency (%)
TiO2-SiO2-550	39.72 ± 1.6
N–TiO2-SiO2-350	16.49 ± 0.4
N–TiO2-SiO2-400	20.64 ± 0.5
N–TiO2-SiO2-450	41.10 ± 1.2
N–TiO2-SiO2-500	46.40 ± 1.4
N–TiO2-SiO2-550	49.48 ± 1.6
N–TiO2-SiO2-600	56.03 ± 1.7
N–TiO2-SiO2-700	40.41 ± 1.6
N–TiO2-SiO2-900	27.91 ± 1.1

Figure 5. Phenol removal efficiency of different catalysts according to time under natural sunlight. The experiment was carried out outdoor in Hochiminh city from 11:00 am to 13:00 pm on 17 September, 2007 with the average light intensity of 80 klux.