高等学校化学学报 ›› 2025, Vol. 46 ›› Issue (9): 20250109.doi: 10.7503/cjcu20250109

• 物理化学 • 上一篇    下一篇

Pt/Cd-TiO2选择性催化CO2加氢反应的性能

张明文1, 周杰2, 王兆宇1()   

  1. 1.福建技术师范学院食品软塑包装技术福建省高校工程研究中心,福清 350300
    2.福州大学化工学院,福州 350000
  • 收稿日期:2025-04-11 出版日期:2025-09-10 发布日期:2025-06-24
  • 通讯作者: 王兆宇 E-mail:1058238843@qq.com
  • 基金资助:
    福建省科技计划面上项目(2024J01969)

Selective Catalytic Performance of Pt/Cd-TiO2 for CO2 Hydrogenation Reactions

ZHANG Mingwen1, ZHOU Jie2, WANG Zhaoyu1()   

  1. 1.Fujian Provincial Engineering Research Center for Food Flexible Packaging Technology,Fujian Polytechnic Normal University,Fuqing 350300,China
    2.College of Chemical Engineering,Fuzhou University,Fuzhou 350000,China
  • Received:2025-04-11 Online:2025-09-10 Published:2025-06-24
  • Contact: WANG Zhaoyu E-mail:1058238843@qq.com
  • Supported by:
    the Science and Technology General Program of Fujian Province, China(2024J01969)

摘要:

CO2加氢过程中间体CO在分子水平上的吸附/脱附行为会显著影响产物选择性. 本文采用浸渍法制备了Pt/Cd-TiO2催化剂. 通过X射线衍射(XRD)、 H2气程序升温还原(H2-TPR)、 拉曼光谱(Raman)、 电子顺磁共振波谱(ESR)、 透射电子显微镜(TEM)、 X射线光电子能谱(XPS)、 CO2程序升温脱附(CO2-TPD)和N₂气吸附-脱附实验等表征手段对Pt/Cd-TiO2催化剂进行表征, 并将其应用于CO2加氢反应中. 活性测试结果显示, Pt/TiO2加氢产物中CO选择性是87.5%, CH4选择性是12.5%. 随着Cd2+的引入, Pt/Cd-TiO2的加氢产物中CO选择性提升至98.1%, CH4选择性降低至1.9%. 以Pt/Cd-TiO2为催化剂, CO的生成温度降低至225 ℃(Pt/TiO2是250 ℃). 原位傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)分析结果表明, Cd2+的引入能够降低Pt纳米颗粒(Pt NPs)表面的电子密度, Pt NPs表面电子密度的降低有利于吸附态CO(COads)脱附生成气态CO, 同时抑制COads加氢生成CH4. 在CO甲烷化实验中, Cd2+的引入使CH4产量降低了约6.6倍, 证明Cd2+抑制了CO甲烷化生成CH4, 这与Pt/Cd-TiO2在CO2加氢中CO选择性提升的结果一致. 通过多种阳离子(Cd2+, Mn2+, Ba2+, K+, Na+)对Pt/TiO2进行修饰, 均能提升CO选择性, 其中Pt/Cd-TiO2表现出最高的CO选择性.

关键词: 二氧化碳加氢, Pt/Cd-TiO2催化剂, 电子密度, 一氧化碳选择性, 一氧化碳吸附

Abstract:

The adsorption/desorption of the key intermediate at the molecular level in CO2 hydrogenation deserves significant attention since the intermediate stability can greatly affect the products selectivity. In this paper, the Pt/Cd-TiO2 catalysts were synthetized by impregnation method. The Pt/Cd-TiO2 catalyst is characterized through X-Ray diffraction(XRD), H2-temperature programmed reduction(H2-TPR), Raman spectra, electron spin resonance(ESR), transmission electron microscope(TEM), X-ray photoelectron spectroscopy(XPS), CO2 temperature programmed desorption(CO2-TPD), and N2 sorption experiments. With the introduction of Cd2+, CO selectivity increases to 98.1% and CH4 selectivity decreases to 1.9% over Pt/Cd-TiO2 compared to Pt/TiO2(87.5% for CO and 12.5% for CH4) during CO2 hydrogenation. Additionally, CO was produced at 225 ℃ over Pt/Cd-TiO2, which is 25 ℃ lower than Pt/TiO2 catalyst(250 ℃). In situ FTIR and XPS measurements reveal that the Cd2+ could reduce the electron density of Pt nanoparticles(Pt NPs), and the reduced electron density of Pt NPs will contribute to the desorption of adsorbed COads into CO in the gas phase and inhibit the hydrogenation of COads to produce CH4. During CO methanation contrast experiments, CH4 evolution decreases by approximately 6.6 times with the introduction of Cd2+, indicating that Cd2+ hinders the reaction of CO with H to produce CH4, in accordance with the increased CO selectivity in CO2 hydrogenation over Pt/Cd-TiO2. The CO selectivity was all improved over Pt/TiO2 promoted with several cations(Cd2+, Mn2+, Ba2+, K+ and Na+), and Pt/Cd-TiO2 exhibits the highest CO selectivity. This study sheds light on the enhanced CO evolution over Pt/Cd-TiO2 in CO2 hydrogenation and provides guidance for catalyst design.

Key words: CO2 hydrogenation, Pt/Cd-TiO2 catalyst, Electron density, CO selectivity, CO binding

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