Facile Synthesis and Characterization of N-Doped TiO₂ Photocatalyst and Its Visible-Light Activity for Photo-Oxidation of Ethylene

Table 1

Characteristics and rate constant of N-doped TiO₂ prepared at various N/Ti ratio and calcinations temperature.

Sample	BET				XRD		SEM	UV-vis		Activity
	Specific surface area	Pore size	Pore volume	Adsorption type^a	Phase content^b	Crystalline size^c	Size	Band gap^d		Rate constant
	m^2/g	nm	cm^3/g	cm^3/g	A/R/B (%)	nm	nm	Eg1 (eV)	Eg2 (eV)	×10^−2 h^−1
N00T2	258.9	3.4	0.28	IV	78/00/22	14	—	—	—	—
N00T3	144.7	4.8	0.24	IV	79/00/22	17	—	2.03	2.99	—
N00T4	70.1	5.3	0.25	IV	82/00/18	24	—	—	3.04	—
N00T5	65.8	6.2	0.17	IV	86/00/14	55	22	—	3.05	0.63^*
N00T6	19.5	9.6	0.08	IV	92/08/00	113	—	—	2.91	—
N00T7	0.5	18.3	0.01	V	28/72/00	138	—	—	2.87	—
N00T8	0.2	25.9	0.00	V	06/94/00	155	—	—	—	—
N50T3	144.8	4.8	0.24	IV	100/00/0	31	—	2.51	3.18	1.72^#
N100T3	231.7	3.9	0.28	IV	100/00/0	28	—	2.51	3.06	1.09^#
N150T3	186.1	4.0	0.27	IV	100/00/0	27	—	2.46	3.12	1.93^#
										0.87^*
N200T3	260.4	3.5	0.27	IV	100/00/0	25	—	2.52	3.05	1.29^*
N150T2	319.9	3.2	0.22	IV	—	—^e	—	—	—	—
N150T4	61.0	6.6	0.16	IV	100/00/0	36	—	2.38	3.10	1.50^*
N150T5	45.3	6.9	0.13	IV	100/00/0	37	21.3	2.39	3.13	1.76^*
N150T6	34.2	9.3	0.11	IV	100/00/0	62	—	—	3.01	1.54^*
N150T7	0.8	29.5	0.03	V	78/22/00	108	—	—	2.92	0.01^*
N150T8	1.6	39.7	0.04	V	58/42/00	113	—	—	2.92	0.00^*
P25	51.2	18.7	0.25	IV	82/18/00	62	—		3.04	0.47^*

Adsorption isotherm type and hysteresis loop were based on the IUPAC manual; ^bA, R, and B denote anatase, rutile, and brookite, respectively; ^cfrom XRD data using Scherer formula; ^dthe band gap is determined by the plot of ()^1/2 versus photon energy, as shown in Figure 4; ^eno obvious characteristic pattern of crystal to calculate the size; ^*experimental conditions: reaction temp. = 20°C, R.H. = 63%, = 140 ppmv, light intensity = 0.62 mW/cm²; ^#experimental conditions: reaction temp. = 20°C, R.H. = 53%, = 85 ppmv, light intensity = 0.62 mW/cm².