化学学报 ›› 2023, Vol. 81 ›› Issue (3): 231-238.DOI: 10.6023/A22120509 上一篇    下一篇

研究论文

W量对Pt/GaWZrOx催化剂结构及甘油选择氢解性能的影响

姜兰a, 范义秋, 张晓昕a, 裴燕b, 闫世润a, 乔明华a,*(), 范康年a, 宗保宁a,*()   

  1. a 复旦大学化学系 上海市分子催化和功能材料重点实验室 上海 200438
    b 中国石化石油化工科学研究院 催化材料与反应工程国家重点实验室 北京 100083
  • 投稿日期:2022-12-26 发布日期:2023-02-17
  • 基金资助:
    国家自然科学基金(22272030); 石油化工催化材料与反应工程国家重点实验室(中国石油化工股份有限公司石油化工科学研究院)开放基金及上海市科委科技基金(19DZ2270100)

Effect of W Content on Structure and Catalytic Performance of Pt/GaWZrOx Catalysts in Glycerol Selective Hydrogenolysis

Lan Jianga, Yiqiu Fan, Xiaoxin Zhanga, Yan Peib, Shirun Yana, Minghua Qiaoa(), Kangnian Fana, Baoning Zonga()   

  1. a Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438, China
    b State Key Laboratory of Catalytic Materials and Reaction Engineering, Research Institute of Petroleum Processing, SINOPEC, Beijing 100083, China
  • Received:2022-12-26 Published:2023-02-17
  • Contact: E-mail: mhqiao@fudan.edu.cn; zongbn.ripp@sinopec.com; Tel.: 021-31244679
  • Supported by:
    National Natural Science Foundation of China(22272030); State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC), and Science and Technology Commission of Shanghai Municipality(19DZ2270100)

在甘油选择氢解制1,3-丙二醇(1,3-PDO)反应中, Pt-WOx催化剂体系因其高活性和高选择性而受到研究者的广泛关注. 本工作制备了W量不同的Ga掺杂GaWZrOx固体酸(GaWZ), 然后作为载体采用浸渍法制备了Pt/GaWZ催化剂, 系统考察了W的量对催化剂物化性质和催化性能的影响. CO化学吸附和X射线光电子能谱(XPS)表征发现, 随着GaWZ载体中W量的增加, 其上负载的Pt的分散度先增加, 在10% (w) W的Pt/GaWZ(10)催化剂上达到最高值86%, 然后在15% (w) W时降低. 紫外-可见漫反射(UV-Vis DRS)、傅里叶变换红外(FTIR)和XPS表征表明, Pt/GaWZ催化剂中的W与四方相ZrO2表面的Zr—OH基团存在较强作用, 形成了单分散的WOx物种; 当大于7.5% (w) W时, 开始出现第二层WOx物种. 单分散的WOx物种可能是Pt分散度提高的重要原因. 由程序升温氨脱附(NH3-TPD)和吡啶吸附红外(Py-IR)表征结果可见, W的量越高, 催化剂的酸量越大, Brønsted酸和Lewis酸同时增加. 在甘油氢解反应中, 随着W的增加, Pt/GaWZ催化剂上的甘油转化率呈火山型变化趋势, 而目标产物1,3-PDO的选择性则持续提高. 1,3-PDO得率在Pt/GaWZ(10)催化剂上达到最高, 为47.5%, 而且该催化剂有良好的套用稳定性. 根据表征结果, 我们推测Pt的分散度及Pt与WOx物种之间的协同作用决定了Pt/GaWZ催化剂在甘油氢解反应中的活性; 而1,3-PDO选择性与Brønsted酸量之间呈现的良好的线性关系, 说明WOx物种上的Brønsted酸位是决定Pt/GaWZ催化剂上1,3-PDO选择性的关键.

关键词: 钨含量, 甘油氢解, 1,3-丙二醇, 铂分散度, Brønsted酸

The Pt-WOx catalyst system has received much attention for its high activity and selectivity in glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO). In this work, the Ga-doped GaWZrOx solid acid supports (GaWZ) with different W contents were prepared, and then Pt/GaWZ catalysts were prepared by the wetness impregnation method. The effects of the W contents on the physicochemical properties and catalytic performance of the Pt/GaWZ catalysts were systematically investigated. CO chemisorption and X-ray photoelectron spectroscopy (XPS) characterizations revealed that the dispersion of Pt on the GaWZ supports first increasesd with the increase in the W content, reached a maximum of 86% on the Pt/GaWZ(10) catalyst with 10% (w) of W, and then decreased at 15% (w) of W. UV-Vis diffuse reflectance (UV-Vis DRS), Fourier transform infrared (FTIR), and XPS characterization showed that the W in the Pt/GaWZ catalysts interacted with the Zr—OH functional groups on the tetragonal phase ZrO2, thus forming mono-dispersed WOx species. When the W content was greater than 7.5% (w), the second layer of the WOx species began to emerge. The mono-dispersed WOx species may be conducive to the high dispersion of Pt. The results of the temperature-programmed desorption of NH3 (NH3-TPD) and pyridine adsorption infrared (Py-IR) characterizations showed that the higher the W content, the higher the amount of the acid on the catalyst, with the simultaneous increase in the amounts of both the Brønsted acids and Lewis acids. In glycerol hydrogenolysis over the Pt/GaWZ catalysts, with the increase in the W content, the glycerol conversion evolved in a volcano-shaped trend, while the selectivity to the target product 1,3-PDO increased monotonically. The highest yield of 1,3-PDO of 47.5% was achieved over the Pt/GaWZ(10) catalyst, and the catalyst also displayed excellent recycling stability. On the basis of the characterization results, we propose that the Pt dispersion and the synergistic interaction between Pt and WOx species determine the activity of the Pt/GaWZ catalysts in glycerol hydrogenolysis, and the Brønsted acid site pertaining to the WOx species is the key to determine the selectivity to 1,3-PDO over the Pt/GaWZ catalysts, as evidenced by the good linear relationship between the 1,3-PDO selectivity and the amount of the Brønsted acid sites.

Key words: W content, glycerol hydrogenolysis, 1,3-propanediol, Pt dispersion, Brønsted acid