Co3O4-SnO2 Hollow Heteronanostructures: Facile Control of Gas Selectivity by Compositional Tuning of Sensing Materials via Galvanic Replacement

Hyun Mook Jeong, Jae Hyeok Kim, Seong Yong Jeong, Chang Hoon Kwak, Jong Heun Lee

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Co3O4 hollow spheres prepared by ultrasonic spray pyrolysis were converted into Co3O4-SnO2 core-shell hollow spheres by galvanic replacement with subsequent calcination at 450 °C for 2 h for gas sensor applications. Gas selectivity of the obtained spheres can be controlled by varying the amount of SnO2 shells (14.6, 24.3, and 43.3 at. %) and sensor temperatures. Co3O4 sensors possess an ability to selectively detect ethanol at 275 °C. When the amount of SnO2 shells was increased to 14.6 and 24.3 at. %, highly selective detection of xylene and methylbenzenes (xylene + toluene) was achieved at 275 and 300 °C, respectively. Good selectivity of Co3O4 hollow spheres to ethanol can be explained by a catalytic activity of Co3O4; whereas high selectivity of Co3O4-SnO2 core-shell hollow spheres to methylbenzenes is attributed to a synergistic effect of catalytic SnO2 and Co3O4 and promotion of gas sensing reactions by a pore-size control of microreactors. (Figure Presented).

Original languageEnglish
Pages (from-to)7877-7883
Number of pages7
JournalACS Applied Materials and Interfaces
Issue number12
Publication statusPublished - 2016 Mar 30



  • CoO
  • galvanic replacement
  • gas sensor
  • heterostructure
  • methylbenzene
  • SnO

ASJC Scopus subject areas

  • Materials Science(all)

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