Insights into the mechanism of low-temperature H2S oxidation over Zn–Cu/Al2O3 catalyst

Mengxue Yin, Zhichao Yun, Feiyue Fan, Suresh C. Pillai, Zhihao Wu, Yan Zheng, Long Zhao, Hailong Wang, Hong Hou*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Odor pollution caused by toxic chemicals with low human olfactory thresholds, such as hydrogen sulfide (H2S), has become a major cause of environmental grievance world-wide. Although the low-temperature (<180 °C) catalytic oxidation of H2S using metal oxides has received widespread attention, desulfurization performance is not ideal. Herein, a series of Zn–Cu/Al2O3 catalysts were developed using an impregnation method based on the Al2O3 hydrophilicity and the effects of zinc loading on the catalyst physicochemical properties and performance were systematically studied. The catalysts were characterized using inductively coupled plasma-optical emission spectrometry (ICP–OES), N2 adsorption–desorption isotherms, scanning electron microscopy with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). It was found that optimization of zinc doping could improve the hydrophilicity of the catalyst, and hence its activity. Catalytic activity was also dependent on operational parameters such as temperature, humidity and space velocity. The Zn3Cu3 catalyst exhibited the highest breakthrough capacity of 353.91 mg/g at 50 °C and at a relative humidity of 50%. The excellent desulfurization performance was attributed to oxygen vacancies contributed by CuO, Cu2O and ZnO, which facilitated the conversion of H2O into hydroxyl radicals. Consequently, a hydroxyl radical-induced desulfurization mechanism over Zn–Cu/Al2O3 is proposed. This work provides a potential green and efficient catalyst for the selective oxidation of H2S.

Original languageEnglish
Article number133105
JournalChemosphere
DOIs
Publication statusAccepted/In press - 2021
Externally publishedYes

Keywords

  • Catalytic oxidation
  • Desulfurization mechanism
  • Hydrogen sulfide
  • Zn–Cu/AlO

ASJC Scopus subject areas

  • Environmental Engineering
  • Chemistry(all)
  • Environmental Chemistry
  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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