高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (6): 20220126.doi: 10.7503/cjcu20220126

• 物理化学 • 上一篇    下一篇

CuO/BiVO4光催化剂的制备及光催化CO2还原性能

宋颖颖, 黄琳, 李庆森, 陈立妙()   

  1. 中南大学化学化工学院, 长沙 410083
  • 收稿日期:2022-03-01 出版日期:2022-06-10 发布日期:2022-04-15
  • 通讯作者: 陈立妙 E-mail:chenlimiao@csu.edu.cn
  • 基金资助:
    国家自然科学基金(21776317);湖南省自然科学基金(2021JJ30787);中南大学中央高校基本科研业务费专项资金(1053320210679)

Preparation of CuO/BiVO4 Photocatalyst and Research on Carbon Dioxide Reduction

SONG Yingying, HUANG Lin, LI Qingsen, CHEN Limiao()   

  1. School of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China
  • Received:2022-03-01 Online:2022-06-10 Published:2022-04-15
  • Contact: CHEN Limiao E-mail:chenlimiao@csu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21776317);the Natural Science Foundation of Hunan Province, China(2021JJ30787);the Fundamental Research Funds for the Central Universities of Central South University, China(1053320210679)

摘要:

基于类十面体钒酸铋(BiVO4)和氧化铜(CuO)纳米颗粒, 构筑了CuO/BiVO4异质结光催化剂; 利用X射线衍射仪(XRD)、 X射线光电子能谱仪(XPS)、 扫描电子显微镜(SEM)、 紫外-可见吸收光谱(UV-Vis)、 光电流响应谱(I-t)、 电化学阻抗谱(EIS)和荧光发射光谱(PL)对催化剂的形貌、 结构和光电性能进行了表征和分析. 结果表明, CuO纳米颗粒均匀地负载在BiVO4的表面, 通过控制铜源的用量可以调节CuO的含量, 其含量对CuO/ BiVO4异质结的可见光吸收能力和光生载流子的分离效率有很大的影响. 在气固反应体系下, 对CuO/BiVO4异质结的光催化还原CO2的性能进行了研究. 结果显示, 光催化还原CO2的主要产物为CO和CH4; 随着CuO含量的增加, CO的产率逐渐降低, 而CH4的产率先增加后降低, 最优化催化剂CuO/BiVO4的CO和CH4的产率分别为0.62和1.81 μmol·g-1·h-1, 对CH4的选择性达到最大值(93%). 能带结构分析和电子顺磁共振(EPR)测试结果表明, CuO/BiVO4中光生电荷的转移符合Z型转移机制. Z型异质结构的形成, 促进了光生电子和空穴的分离, 提升了催化体系的氧化还原能力.

关键词: 光催化, 二氧化碳还原, Z型异质结, 甲烷选择性

Abstract:

The CuO/BiVO4 heterojunction photocatalyst was constructed based on decahedral bismuth vanadate (BiVO4) and copper oxide(CuO) nanoparticles. The morphology, structure and optoelectronic properties of the catalysts were analyzed by X-ray diffractometer(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), ultraviolet-visible absorption spectroscopy(UV-Vis), photocurrent response spectroscopy(I-t), electrochemical impedance spectroscopy(EIS) and fluorescence emission spectroscopy(PL). The results show that CuO nanoparticles are uniformly supported on the surface of BiVO4, and the content of CuO can be adjusted by controlling the amount of copper source. The content of CuO has a great effect on the visible light absorption capacity and the separation efficiency of photogenerated carriers of the CuO/BiVO4 heterojunction. The photocatalytic CO2 reduction performance of CuO/BiVO4 heterojunction under gas-solid reaction system was investigated. The results showed that the main products of photocatalytic reduction of CO2 were CO and CH4. With the increase of CuO content, the yield of CO decreased gradually, while the yield of CH4 increased first and then decreased. The CO and CH4 yields of the optimized catalyst CuO/BiVO4 were 0.62 and 1.81 μmol·g-1·h-1, respectively, and the selectivity to CH4 reached the maximum value(93%). Band structure analysis and electron paramagnetic resonance(EPR) test results show that the transfer of photogenerated charges in CuO/BiVO4 conforms to the Z-type transfer mechanism. The formation of the Z-type heterostructure promotes the separation of photogenerated electrons and holes and enhances the redox capacity of the catalytic system.

Key words: Photocatalyst, Carbon dioxide reduction, Z-type heterojunction, CH4 selectivity

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