CuO/TiO2纳米纤维可见光催化CO2合成甲醇

Visible light driven reduction of CO2 to methanol over CuO/TiO2 nanofibers

摘要:

以介孔SiO2球为模板，TiCl4为前驱体, 采用气相生长法制备了直径为8~10 nm的TiO2纳米纤维，然后采用浸渍法制备了具有异质结结构的CuO/TiO2纳米纤维, 在可见光照射下催化CO2合成甲醇。通过SEM、TEM、XPS、UV-Vis、XRD、PL对催化剂进行了表征。结果表明：TiO2纳米纤维较锐钛矿TiO2纳米颗粒和德固赛TiO2纳米颗粒(P25)荧光强度明显降低，光生电子-空穴对更加稳定。通过在TiO2纳米纤维上负载CuO形成异质结结构后，进一步降低了催化剂的荧光强度，也增强了在可见光区的吸收。在300W氙灯照射5h进行光催化CO2合成甲醇实验中，P25负载CuO后，催化合成甲醇产量为676μmol/g-cat，而负载了CuO的TiO2纳米纤维，甲醇产量达1791μmol/g-cat，较CuO/P25提高了165%。

Abstract:

TiO2 nanofibers with a diameter of 8~10nm were successfully prepared by vapor-phase growth with mesoporous SiO2 spheres as templates and TiCl4 as precursor. Furthermore, CuO/TiO2 nanofibers with a heterojunction structure were also prepared through impregnation method for visible-light driven reduction of CO2 to methanol. XRD, SEM, TEM, XPS, ultraviolet visible diffuse reflection(UV-Vis) and photoluminescence(PL) were used to characterize the crystal structure, morphology, chemical valence, visible light absorption intensity and electron-hole recombination rate, respectively. Compared to P25 and anatase TiO2 nanoparticles, TiO2 nanofibers show much lower fluorescence intensity and more stable photogenerated electron-hole pair. Loading of CuO onto TiO2 nanofibers may further reduce the fluorescence intensity and enhance absorption of visible light. Under the irradiation of 300W xenon lamp for 5h, the yields of methanol over CuO/P25 was 696μmol/g-cat, and further enhanced to 1791μmol/g-cat over CuO/TiO2 nanofibers, 165% higher than that over CuO/P25.