化学学报 ›› 2025, Vol. 83 ›› Issue (3): 247-255.DOI: 10.6023/A24110345 上一篇    下一篇

研究论文

金属原子表面修饰TiO2光电催化CO2与$NO_{2}^{-}$共还原合成尿素

王瑛琦a,b,, 常嘉怡a,b,, 李敏a,b,*(), 梁红a,b, 李知恒a,b, 谢文富a,b, 王强a,b,*()   

  1. a 北京林业大学环境科学与工程学院 水体污染源控制技术北京市重点实验室 北京 100083
    b 北京林业大学环境科学与工程学院 污染水体源控制与生态修复技术北京市高等学校工程研究中心 北京 100083
  • 投稿日期:2024-11-13 发布日期:2025-02-03
  • 基金资助:
    国家自然科学基金(52300125); 国家自然科学基金(22109004); 中央高校基本科研业务费(BLX202259); 中央高校基本科研业务费(BLX202257)

Photoelectrocatalytic Urea Synthesis via co-Reduction of CO2 and $NO_{2}^{-}$ over Metallic Surface Modified TiO2

Yingqi Wanga,b,, Jiayi Changa,b,, Min Lia,b(), Hong Lianga,b, Zhiheng Lia,b, Wenfu Xiea,b, Qiang Wanga,b()   

  1. a Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
    b Beijing Engineering Research Center of Source Control and Ecological Restoration Technology for Contaminated Water Bodies, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
  • Received:2024-11-13 Published:2025-02-03
  • Contact: *E-mail: limin2022@bjfu.edu.cn; qiangwang@bjfu.edu.cn
  • About author:
    These authors contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(52300125); National Natural Science Foundation of China(22109004); Fundamental Research Funds for the Central Universities(BLX202259); Fundamental Research Funds for the Central Universities(BLX202257)

采用温和的光电催化技术将大气中CO2与水体污染物$NO_{2}^{-}$共还原合成高附加值化学品尿素是实现减污降碳目标的有效途径之一. 然而该反应为双底物分子参与的12电子共还原反应, 反应难度较大、路径复杂、对催化剂要求较高, 目前针对该反应还鲜有报道. 本工作采用水热法结合光沉积法制备了Ru、Cu、Zn金属原子表面修饰的TiO2催化材料, 并研究了其光电催化CO2与$NO_{2}^{-}$共还原合成尿素的性能. 实验结果表明: 5% (w)修饰的Ru-TiO2在-0.1 V (vs. RHE)、光照2 h条件下, 尿素产率为50.58 μmol•g⁻1•h⁻1, 法拉第效率(FE)为16.66%, 是TiO2的1.65倍. 紫外可见漫反射光谱(DRS)和电化学阻抗谱(EIS)表明TiO2材料表面修饰的Ru原子能够有效地提高材料的光吸收、电荷分离和迁移性能. 光生电子从TiO2转移到Ru原子位点, 参与C—N偶联反应. 本工作为光电催化尿素合成体系中的高效催化剂设计提供理论指导, 为实现减污降碳提供新的思路和途径.

关键词: 二氧化钛, 光电催化, 二氧化碳, 亚硝酸根, 尿素

Using mild photoelectrocatalytic technology to co-reduce CO2 from the atmosphere and $NO_{2}^{-}$ from water pollutants into high-value-added chemical urea is an effective approach to achieving pollution reduction and carbon reduction goals. However, this reaction involves a 12-electron co-reduction with dual-substrate molecules, making it highly challenging with a complex pathway and high demands on the catalyst. So, there are few reports on this reaction currently. In this study, Ru, Cu, and Zn atom-modified TiO2 catalytic materials (Ru, Cu, and Zn-TiO2) were prepared via a hydrothermal method combined with photodeposition method. The specific synthesis processes are as follows: titanium butoxide was dropwise added into a H2O/HCl mixed solution. Then the solution and fluorine-doped tin oxide (FTO) substrate were transferred and sealed in a Teflon-lined stainless-steel autoclave and heated to 150 ℃ for 20 h. The obtained TiO2 photoelectrode was annealed in a muffle furnace at 350 ℃ for 2 h. The TiO2 with different metal atom surface modifications were prepared by adding metal salt solution and methanol in a beaker, placing the TiO2 photoelectrode in the solution and irradiating it with a 300 W xenon lamp for 1 h. We conducted catalytic urea synthesis experiments by using three-electrode configuration in a H-type quartz cell equipped with pretreated Nafion 117 membrane. The as-prepared semiconductor, Ag/AgCl electrode and Pt foil were utilized as the photocathode, reference and counter electrodes, respectively. 0.1 mol•L⁻1 KNO2 was used as the electrolyte in both the cathode and anode compartments. CO2 gas was injected into the cathode chamber during the photoelectrocatalytic test. The experimental results showed that Ru-TiO2 modified with 5% (w) Ru achieved a urea yield of 50.58 μmol•g⁻1•h⁻1 and a Faradaic efficiency (FE) of 16.66% under 2 h light irradiation at -0.1 V (vs. RHE). The 5% (w) Ru-TiO₂ catalyst exhibits a FE 1.65 times than that of TiO₂ under identical conditions. UV-Vis diffuse reflectance spectra (DRS) and electrochemical impedance spectra (EIS) indicate that Ru atoms can effectively enhance the light absorption, charge separation and transfer of TiO2. Photogenerated electrons transfer from TiO2 to Ru atomic sites, participating in the C—N coupling reaction. This work provides theoretical guidance for designing and synthesizing efficient catalysts for photoelectrocatalytic urea synthesis, offering novel idea and pathway for synergetic control of environmental pollution and carbon emissions.

Key words: titanium dioxide, photoelectrocatalysis, carbon dioxide, nitrite, urea