N掺杂TiO_2光催化剂的制备与表征

Preparation and characterization of N-doped TiO_2 photocatalyst

以饱和尿素溶液水解沉淀工艺制备水合TiO2，将水合TiO2在400～700℃的空气气氛下煅烧2h，制得淡黄色的N掺杂TiO2光催化剂。对样品的煅烧过程进行分析，采用XRD，TEM，BET及UV-Vis等对其物相、粒径、比表面积、掺氮量、吸光性能及可见光催化性能等进行测试和表征。结果表明：掺杂氮元素主要以形成配合物分子形式均匀分布在煅烧前驱体中，在TiO2从无定形转变为锐态矿型的过程中，掺杂氮元素以Ti—N化学键的形式进入到Ti02晶格中；该N掺杂TiＯ2光催化剂样品的粒径为10-30nm，比表面积为30～70m^2／g，掺氮量约3％，能吸收波长400nm以上的可见光；样品在波长主峰420nm的荧光灯激发下，反应3h后对2，4一二氯苯酚的光催化降解率超过40％。

Under 400-700 ℃ and ambient atmosphere, N-doped TiO2 photocatalyst was prepared by calcining hydrated titanium dioxide which was obtained by using saturate urea solutions as precipitant. The obtained yellow samples were characterized by XRD, TEM and UV-Vis, the calcine process was analyzed, and their photocatalytic activities under visible light were also evaluated. The results indicate that the presence of nitrogen element in the precursor is in the form of complex formation, and nitrogen is doped into TiO2 lattice in the form of Ti--N bond when the crystalline structure of TiO2 changes from amorphous to anatase. The samples grain sizes, specific surface area and nitrogen doping contents are 10-30 urn, 30-70 m^2/g and 3%, respectively, and can absorb visible light with wavelength above 400 urn. Photocatalytic activities results show that over 40% 2,4-dichlorophenol can be degraded under visible light irradiation after 3 h reaction.