N掺杂TiO_2纳米纤维高可见光催化CO_2合成甲醇  

Photocatalytic Reduction of Carbon Dioxide to Methanol over N-doped TiO_2 Nanofibers under Visible Irradiation

作　　者：柯银环 曾敏[1] 姜宏[1] 熊春荣[1] KE Yin-Huan;ZENG Min;JIANG Hong;XIONG Chun-Rong(Special Glass Key Lab of Hainan Province,Skate Key Laboratory of Marine Resource Utilization in South China Sea,Hainan University,Haikou 570228,Chin)

机构地区：[1]海南大学南海海洋资源利用国家重点实验室海南省特种玻璃实验室,海口570228

出　　处：《无机材料学报》2018年第8期839-844,共6页Journal of Inorganic Materials

基　　金：海南省重大科技计划项目(ZDKJ2017011);海南省重点研发计划项目(ZDYF2016017)~~

摘　　要：采用气相生长法在介孔SiO_2球的表面上制备了?8~10 nm的TiO_2纳米纤维,采用相同的方法,还成功地制备了氮掺杂的TiO_2(N-TiO_2)纳米纤维,它具有更高的可见光催化活性。采用X射线光电子能谱(XPS)、紫外光电子能谱(UPS)、X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)、紫外-可见分光光度计(UV-Vis)、荧光分光光度计(PL)等对样品进行了测试分析。TiO_2纳米纤维具有高结晶度的锐钛矿晶型,掺氮后的TiO_2纳米纤维带隙变窄,在可见光波段有明显的吸收,同时,光生电子还原能力更强,大大提高了可见光下催化还原CO_2合成甲醇的产率。在300 W氙灯光照2 h后,用纯TiO_2纤维催化CO_2合成甲醇,产率为493.4μmol×g^(–1)?h^(–1),转换频率(TOF)为0.089 h^(–1);以N-TiO_2为催化剂合成甲醇产率提高了40.1%,达695.1μmol?g^(–1)?h^(–1),转换频率(TOF)提高了40.4%,为0.125 h^(–1)。TiO2 nanofibers with a diameter size of 8^（–1）0 nm were prepared on the surface of the mesoporous SiO2 spheres through a vapor-phase growth method. And nitrogen doped TiO2（N-TiO2） nanofibers were also successfully fabricated in the same way. The N atoms replaced the oxygen sites in the lattices of TiO2. The N-TiO2 nanofibers exhibited a highly catalytic activity under visible irradiation. XPS, UPS, XRD, SEM, TEM, UV-Vis, and PL were used to analyze and characterize the nanofibers. The annealed nanofibers were composed of highly crystalline anatase phase. Nitrogen doping narrowed band gap of the TiO2 nanofibers and enhanced absorption of the visible light. Meanwhile, photo-generated electrons over the N-TiO2 nanofibers exhibited more reductive potential than those over the TiO2 nanofibers. Thus, methanol yield was remarkably improved in CO2 photocatalytic reduction. Upon irradiation of 300 W Xe lamp for 2 h, methanol yield was 493.4 μmol？g^（–1）？h^（–1） over the N-doped TiO2 nanofibers, and the corresponding turnover frequency（TOF） was 0.089 h^（–1）. Comparatively, methanol yield reached 695.1 μmol？g^（–1）？h^（–1） for N-TiO2 with a TOF of 0.125 h^（–1）, which enhanced by 40.1% and 40.4%, respectioely.

关 键 词：CO2 可见光 甲醇 TiO2纳米纤维 

分 类 号：TQ174[化学工程—陶瓷工业]