CuO/Er-Yb-TiO2的制备及在模拟可见光下催化CO2合成甲醇  

Preparation of CuO/Er-Yb-TiO2 and Catalytic Synthesis of Methanol from CO2 Under Simulated Visible-light

作　　者：肖洒[1] 谈恒 吴珊妮 曾敏[1] 熊春荣[1] XIAO Sa;TAN Heng;WU Shanni;ZENG Min;XIONG Chunrong(Special Glass Key Laboratory of Hainan Province,State Key Laboratory of Marine Resource Utilization in South China Sea,Hainan University,Haikou 570228,China)

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

出　　处：《材料导报》2020年第2期2005-2009,共5页Materials Reports

基　　金：海南省重大科技计划项目(ZDKJ2017011);国家自然科学基金(51761010)~~

摘　　要：采用溶胶-凝胶法制备了Er^3+和Yb^3+掺杂的TiO2纳米颗粒(Er-Yb-TiO2),并进一步通过浸渍法负载了CuO,得到CuO/Er-Yb-TiO2用于催化还原CO2合成甲醇。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)仪、X射线光电子能谱(XPS)、紫外-可见光谱仪(UV-vis)、荧光分光光度计(PL)等对样品进行了表征。结果表明,在TiO2中掺入Er^3+和Yb^3+,在980 nm近红外光的激发下,可分别获得525 nm(2H11/2→4I 15/2)、549 nm(4S3/2→4I 15/2)和661 nm(4F9/2→4I15/2)的上转换可见光,并抑制了光生电子-空穴对的复合。负载CuO后,增强了TiO2对可见光的吸收,光生电子-空穴对更加稳定。在300 W氙灯模拟可见光下,分别采用纯TiO2、CuO/TiO2、Er-Yb-TiO2和CuO/Er-Yb-TiO2催化还原CO2合成甲醇,反应时间为2 h。结果显示,以纯TiO2为催化剂,甲醇的产率仅为23.9μmol·g^-1;Yb^3+与Er^3+的掺杂量分别为2.5%和1%(均为摩尔分数)的Er-Yb-TiO2获得的甲醇产率提高到116.7μmol·g^-1;CuO/TiO2和CuO/Er-Yb-TiO2由于CuO的负载提高了纳米颗粒对可见光的吸收,所得的甲醇产率分别提高到69.1μmol·g^-1及281.2μmol·g^-1。由此可见,CuO/Er-Yb-TiO2能高效催化还原CO2合成甲醇。Er^3+and Yb^3+co-doped TiO2(Er-Yb-TiO2)nanoparticles were successfully synthesized by employing sol-gel method.Furthermore,CuO was loaded onto the Er-Yb-TiO2 by impregnation method,thus CuO/Er-Yb-TiO2 was obtained,utilizing in catalysis of CO2 reduction to prepare methanol.The characterization of the catalysts samples was carried out by means of scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),X-ray photoelectron spectroscope(XPS),ultraviolet-visible spectrometer(UV-vis)and fluorescence spectrophotometer(PL).According to the analytic results,the doping of Er^3+and Yb^3+in TiO2 would bring about intense upconverted emissions in the visible region at 525 nm,549 nm and 661 nm,which are ascribed to the 2H11/2→4I15/2,4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er^3+,under the excitation of near-infrared light at 980 nm.Additionally,incorporation of Er^3+and Yb^3+in TiO2 also inhabited the recombination of the excited electron-hole pairs.Loading CuO onto the Er-Yb-TiO2 or TiO2 might contribute to the absorption of the visible light and the stability of the photogenerated electron-hole pairs,which resulted in a better photocatalytic performance.Visible-light driven reduction of CO2 for methanol preparation was conducted under irradiation of 300 W Xe lamp for 2 h,taking pure TiO2,CuO/TiO2,Er-Yb-TiO2 and CuO/Er-Yb-TiO2 as catalysts.The results revealed that pure TiO2 showed a methanol yield of 23.9μmol·g&-1,the Er-Yb-TiO2 doped with 2.5mol%Yb^3+and 1mol%Er 3+exhibited a methanol yield of 116.7μmol·g^-1.The methanol yields of CuO/TiO2 and CuO/Er-Yb-TiO2 were raised to 69.1μmol·g^-1 and 281.2μmol·g^-1,due to the increased absorption of visible light by CuO loading.Consequently,CuO/Er-Yb-TiO2 can efficiently catalyze the reduction of CO 2 for methanol preparation.

关 键 词：二氧化钛 稀土 上转换 可见光催化 二氧化碳 甲醇 

分 类 号：TQ034[化学工程]