CuO/ZrO2 catalysts for water-gas shift reaction: Nature of catalytically active copper species

Yanjie Zhang, Chongqi Chen, Xingyi Lin, Dalin Li, Xiaohui Chen, Yingying Zhan, Qi Zheng

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

A series of CuO/ZrO2 catalysts with different Cu loadings (4.1, 6.1 and 8.4 wt.%) were synthesized by a deposition-precipitation method and evaluated with the water-gas shift (WGS) reaction. In order to distinguish the different supported copper oxide species, (NH4)2CO 3-leaching process was conducted on the three CuO/ZrO2 catalysts. The parent and leached catalysts were characterized by ICP-OES, XPS, XRD, N2-physisorption, N2O titration, UV-Vis DRS, H 2-TPR and CO-TPR. The results reveal that three types of copper oxide species are present on the parent CuO/ZrO2 catalysts: (α) highly dispersed CuO that is weakly bound with ZrO2; (β) strongly bound Cu-[O]-Zr species, which can not be leached by (NH 4)2CO3 solution and is possibly associated with the surface oxygen vacancy of ZrO2; (γ) crystalline CuO. The XRD and TEM results of the freshly reduced catalysts disclose that the three types of CuO species are transformed into their corresponding metallic states after the H2-pretreatment. It is found that the reaction rate correlates well with the amount of Cu-[O]-Zr species, indicating the metallic Cu derived from this species should be the catalytically active copper species for the WGS reaction. Moreover, CO-TPR results disclose that the Cu-[O]-Zr species play a significant role in promoting the reactivity of the surface hydroxyl groups, as is thought to be responsible for the high WGS activity of the CuO/ZrO2 catalysts.

Original languageEnglish
Pages (from-to)3746-3754
Number of pages9
JournalInternational Journal of Hydrogen Energy
Volume39
Issue number8
DOIs
Publication statusPublished - 2014 Mar 6

Keywords

  • Active species
  • Copper
  • Surface hydroxyl groups
  • Water-gas shift reaction
  • Zirconia

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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