TiO₂/g-C₃N₄/Fe₂O₃复合光催化剂的制备、表征及其在模拟太阳光下光催化还原CO₂性能  

Preparation and Characterization of TiO2/g-C3N4/Fe2O3 Composite Catalyst and Its Photocatalytic Performance of CO2 Reduction under a Xenon Lamp

作　　者：马宇谦 徐琴 齐秀芳[1] 

机构地区：[1]西南科技大学国防科技学院,四川 绵阳

出　　处：《材料科学》2022年第8期781-792,共12页Material Sciences

摘　　要：光催化还原CO2是改善环境和缓解温室效应的有效方式之一,TiO2、g-C3N4、Fe2O3是目前最具有应用前景的紫外/可见光催化剂。本文采用水热合成法,摩尔比为1:1:1,制备TiO2/g-C3N4/Fe2O3三元复合光催化剂,并采用相同方法和比例制备了二元光催化剂g-C3N4/Fe2O3、TiO2/g-C3N4、TiO2/Fe2O3。通过EDS-SEM、FT-IR、XRD、UV-vis对其形貌、结构和光学性质进行表征,考察了三元和二元光催化剂在氙灯光源(模拟太阳光)的照射下光催化还原CO2的效率。结果表明:三元光催化剂呈纳米级复合在一起,其表面Ti、C、N、Fe、O的原子含量分别为2.91%、18.08%、28.71%、10.40%、39.90%;复合后的三元光催化剂中的TiO2为锐钛型,Fe2O3属于α-Fe2O3;复合三元光催化剂的主要光吸收区域由紫外光区扩宽到了可见光区,约为200~607 nm之间,产生多个带隙,分别为1.64 eV、1.70 eV、2.02 eV,在整个紫外–可见波段有多个吸收,能够实现对光源的充分利用。三元光催化剂光催化CO2反应1 h产生醇的效率为2.0557 µmol∙g−1∙h−1;光反应6 h的平均效率为0.8114 µmol∙g−1∙h−1,随着辐照时间的延长,反应速率变慢,因此单次光催化反应时间不宜过长。Photocatalytic reduction of CO2 is one of the most effective ways to improve the environment and alleviate the greenhouse effect. TiO2, g-C3N4 and Fe2O3 are the most promising UV and/or visible light catalysts at present. In this paper, TiO2/g-C3N4/Fe2O3 ternary photocatalyst was prepared by hydrothermal synthesis method with water as the medium and molar ratio of 1:1:1. The binary photocatalysts g-C3N4/Fe2O3, TiO2/g-C3N4 and TiO2/Fe2O3 were prepared by the same method and proportion. The morphology, structure and optical properties were characterized by EDS-SEM, FT-IR, XRD and UV-vis. The efficiency of ternary and binary photocatalysts in the photocatalytic reduction of CO2 under the irradiation of a xenon lamp (simulated sunlight) was investigated, and the products were characterized by chemical and instrumental methods. EDS-SEM showed that the ternary photocatalyst was nanocomposite, and the atomic contents of Ti, C, N, Fe and O on the surface were 2.91, 18.08, 28.71, 10.40 and 39.90, respectively. By comparing the IR spectra of monadic, binary and ternary photocatalysts, the results show that the ternary photocatalyst still retains the molecular group of monadic photocatalyst. XRD showed that TiO2/g-C3N4/Fe2O3 still retained a monadic molecular structure. According to FT-IR and XRD patterns, TiO2 and Fe2O3 belong to anatase type and α-Fe2O3 respectively. The results of solid UV-vis diffuse reflectance spectra show that the main light absorption region of the composite ternary photocatalyst expands from the ultraviolet region to the visible region, which is about 200~607 nm. Multiple band gaps are generated, which are 1.64 eV, 1.70 eV and 2.02 eV, respectively. There are multiple absorptions in the whole band, which can realize the comprehensive application of light sources. The yield of alcohol produced by ternary photocatalyst was 2.0557 µmol∙g−1∙h−1. The average yield of 6 h photoreaction was 0.8114 µmol∙g−1∙h−1. With the extension of photoreaction time, the reaction rate slowed d

关 键 词：物理化学 CO₂ 光催化 TiO₂/g-C₃N₄/Fe₂O₃ 甲醇 乙醇 

分 类 号：TB332[一般工业技术—材料科学与工程]