Pd-based catalysts promoted by hierarchical porous Al2O3 and ZnO microsphere supports/coatings for ethyl acetate highly active and stable destruction

Mudi Ma; Rui Yang; Chi He; Zeyu Jiang; Jian-Wen Shi; Reem Albilali; Khaled Fayaz; Baojun Liu

doi:10.1016/j.jhazmat.2020.123281

Pd-based catalysts promoted by hierarchical porous Al₂O₃ and ZnO microsphere supports/coatings for ethyl acetate highly active and stable destruction

J Hazard Mater. 2021 Jan 5:401:123281. doi: 10.1016/j.jhazmat.2020.123281. Epub 2020 Jun 22.

Authors

Mudi Ma¹, Rui Yang¹, Chi He², Zeyu Jiang¹, Jian-Wen Shi³, Reem Albilali⁴, Khaled Fayaz⁵, Baojun Liu⁶

Affiliations

¹ State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, PR China.
² State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, PR China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, PR China. Electronic address: chi_he@xjtu.edu.cn.
³ State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, PR China.
⁴ Department of Chemistry, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
⁵ Department of Criminal Justice and Forensic Science, King Fahd Security College, P.O. Box 2511, Riyadh 11461, Saudi Arabia.
⁶ College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, PR China. Electronic address: jbliu@gzu.edu.cn.

PMID: 32629352
DOI: 10.1016/j.jhazmat.2020.123281

Abstract

Developing economical and active materials is of great significance for VOC purification. Here, hierarchical porous Al₂O₃ and ZnO microspheres (Al₂O₃-pm and ZnO-pm) were synthesized by a facile hydrothermal strategy. The urchin-like Al₂O₃-pm and flower-like ZnO-pm possess high specific surface area (especially; external surface area) obviously boost the dispersion of Pd with 29.3 % and 30.1 % over Pd/Al₂O₃-pm and Pd/ZnO-pm, respectively, over 3.4 times higher than those of commercial Al₂O₃- and ZnO-supported counterparts. Pd/Al₂O₃-pm possesses excellent activity and CO₂ yield in ethyl acetate (EA) degradation, with TOF reaches 7.76 × 10^-3 s^-1 at 160 °C under GHSV of 50,000 h^-1. Moreover, Pd/Al₂O₃-pm exhibits satisfied performance in EA-contained binary VOCs oxidation and has high long-term stability under both dry and humid conditions. Both Pd sites and Brønsted acid sites participated in reaction process and initially react with EA to form ethylene and ethanol, respectively. Larger amount Brønsted acid sites over Pd/Al₂O₃-pm promote ethanol formation and C-C cleavage, resulting in different CO₂ yields and EA activation mechanisms. The coating greatly enhances Pd dispersion over Pd supported monolithic catalyst, endowing its desired activity and stability even with a much lower Pd loading. This work promotes the potential application of noble-metal-based monolithic materials in VOC degradation.

Keywords: Catalytic oxidation; Ethyl acetate; Hierarchical porous Al(2)O(3)/ZnO microsphere; Monolithic catalyst; Palladium.