Preparation of N-TiO₂ Using a Microwave/Sol-Gel Method and Its Photocatalytic Activity for Bisphenol A under Visible-Light and Sunlight Irradiation

Table 2

Nitrogen doping ratio of 0.05 NT, 0.1 NT, 0.2 NT, and 0.5 NT.

	0.05 NT	0.1 NT	0.2 NT	0.5 NT
N1/Ti	0.00200	0.00249	0.00546	0.00384
N2/Ti	0.00053	0.00007	0.00009	0.00196
N1/N2	3.8	35.5	63.5	2.0
Total doping N	0.15%	0.16%	0.33%	0.35%

N1 refers to N in N–Ti–O linkages. N2 refers to N in Ti–O–N.