Metal-Organic Framework-Templated PdO-Co3O4 Nanocubes Functionalized by SWCNTs: Improved NO2 Reaction Kinetics on Flexible Heating Film

Seon Jin Choi, Hak Jong Choi, Won Tae Koo, Daihong Huh, Heon Lee, Il Doo Kim

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Detection and control of air quality are major concerns in recent years for environmental monitoring and healthcare. In this work, we developed an integrated sensor architecture comprised of nanostructured composite sensing layers and a flexible heating substrate for portable and real-time detection of nitrogen dioxide (NO2). As sensing layers, PdO-infiltrated Co3O4 hollow nanocubes (PdO-Co3O4 HNCs) were prepared by calcination of Pd-embedded Co-based metal-organic framework polyhedron particles. Single-walled carbon nanotubes (SWCNTs) were functionalized with PdO-Co3O4 HNCs to control conductivity of sensing layers. As a flexible heating substrate, the Ni mesh electrode covered with a 40 nm thick Au layer (i.e., Ni(core)/Au(shell) mesh) was embedded in a colorless polyimide (cPI) film. As a result, SWCNT-functionalized PdO-Co3O4 HNCs sensor exhibited improved NO2 detection property at 100 °C, with high sensitivity (S) of 44.11% at 20 ppm and a low detection limit of 1 ppm. The accelerated reaction and recovery kinetics toward NO2 of SWCNT-functionalized PdO-Co3O4 HNCs were achieved by generating heat on the Ni(core)/Au(shell) mesh-embedded cPI substrate. The SWCNT-functionalized porous metal oxide sensing layers integrated on the mechanically stable Ni(core)/Au(shell) mesh heating substrate can be envisioned as an essential sensing platform for realization of low-temperature operation wearable chemical sensor.

Original languageEnglish
Pages (from-to)40593-40603
Number of pages11
JournalACS Applied Materials and Interfaces
Issue number46
Publication statusPublished - 2017 Nov 22


  • CoO nanocubes
  • carbon nanotube
  • flexible gas sensor
  • metal mesh
  • metal-organic framework

ASJC Scopus subject areas

  • Materials Science(all)


Dive into the research topics of 'Metal-Organic Framework-Templated PdO-Co<sub>3</sub>O<sub>4</sub> Nanocubes Functionalized by SWCNTs: Improved NO<sub>2</sub> Reaction Kinetics on Flexible Heating Film'. Together they form a unique fingerprint.

Cite this