物理化学学报2020，Vol.36Issue(3)：48-55,8.DOI:10.3866/PKU.WHXB201905086
棒状金属有机框架结构PCN-222(Cu)/TiO2复合材料的制备及其高效光催化CO2还原性能
Rod-Shaped Metal Organic Framework Structured PCN-222(Cu)/TiO2 Composites for Efficient Photocatalytic CO2 Reduction
摘要
Abstract
The photocatalytic reduction of CO2 has attracted considerable attention owing to the dual suppression of environmental pollution and energy shortage. The technology uses solar energy to convert carbon dioxide into hydrocarbon fuel, which is of great significance for achieving the carbon cycle. The development of low-cost photocatalytic materials is critical to achieving efficient solar energy to fuels conversion. One of the most commonly employed photocatalysts is TiO2. However, it suffers from broad band gap as well as the recombination of photo-excited holes and electron. Hence, in this work, we report the photochemical reduction of CO2 using rod-like PCN-222(Cu)/TiO2 composites as photocatalyst through a simple hydrothermal method, in which TiO2 nanoparticles are anchored at theinterface of the SiC rod PCN-222(Cu). Multiple characterization techniques were used to analyze the structure, morphology, and properties of the PCN-222(Cu)/TiO2 composite. A series of characterizations including X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy, photo-electrochemical, and photoluminescence (PL) confirm the successful preparation of PCN-222(Cu)/TiO2 composites. SEM reveals that the TiO2 nanoparticles are uniformly distributed on the surface of the rod-shaped PCN-222(Cu)/TiO2. XRD results show that PCN-222(Cu) and PCN-222(Cu)/TiO2 composite photocatalysts with good crystal structure were successfully synthesized. According to the DRS results, the prepared PCN-222(Cu)/TiO2 composite samples exhibit characteristic absorption peaks of metalloporphyrins in the visible region. PL spectroscopy, transient photocurrent response, and electrochemical impedance spectroscopy further confirm that the rod-like PCN-222(Cu)/TiO2 samples have high electron-hole pair separation efficiency. By controlling the mass ratio of PCN-222(Cu) and TiO2, the photocatalytic CO2 reduction performance test shows that the 10％ PCN-222(Cu)/TiO2 composite achieves optimal catalytic performance, yielding 13.24 μmol·g?1·h?1 CO and 1.73 μmol·g?1·h?1 CH4, respectively. All the rod-like PCN-222(Cu)/TiO2 composites exhibit better photocatalytic CO2 activity than that of TiO2 nanoparticles or PCN-222(Cu) under the illumination of xenon lamps, which is attributed to charge transport and electron-hole separation capabilities. After three test cycles, the catalytic activity of PCN-222(Cu)/TiO2 photocatalyst was virtually unchanged. The reduction yield of the catalyst increased for 8 h under continuous illumination, indicating that PCN-222(Cu)/TiO2 composites have acceptable stability. The estimation of the band gap curve and the Mote-Schottky curve test show that the lowest unoccupied molecular orbital position of PCN-222(Cu) is more negative than the TiO2 of the conduction band; hence, a possible photocatalytic reaction mechanism of the PCN-222(Cu)/TiO2 composite is proposed. This study provides a new strategy for the integration of metal-organic frameworks and oxide semiconductors to construct efficient photocatalytic systems.关键词
复合材料/金属有机框架/PCN-222(Cu)/光催化CO2还原/TiO2Key words
Composite/Metal-organic frameworks/PCN-222(Cu)/Photocatalytic CO2 reduction/TiO2分类
化学化工引用本文复制引用
段树华,巫树锋,王磊,佘厚德,黄静伟,王其召..棒状金属有机框架结构PCN-222(Cu)/TiO2复合材料的制备及其高效光催化CO2还原性能[J].物理化学学报,2020,36(3):48-55,8.基金项目
The project was supported by the National Natural Science Foundation of China (21663027, 21808189).国家自然科学基金(21663027, 21808189)资助项目 （21663027, 21808189）
