Improved Sensitivity with Low Limit of Detection of a Hydrogen Gas Sensor Based on rGO-Loaded Ni-Doped ZnO Nanostructures

Vijendra Singh Bhati, Sapana Ranwa, Saravanan Rajamani, Kusum Kumari, Ramesh Raliya, Pratim Biswas, Mahesh Kumar

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

We report enhanced hydrogen-gas-sensing performance of a Ni-doped ZnO sensor decorated with the optimum concentration of reduced graphene oxide (rGO). Ni-doped ZnO nanoplates were grown by radio frequency sputtering, rGO was synthesized by Hummer's method and decorated by the drop cast method of various concentration of rGO (0-1.5 wt %). The current-voltage characteristics of the rGO-loaded sensor are highly influenced by the loading concentration of rGO, where current conduction decreases and sensor resistance increases as the rGO concentration is increased up to 0.75 wt % because of the formation of various Schottky heterojunctions at rGO/ZnO interfaces. With the combined effect of more active site availability and formation of various p-n heterojunctions due to the optimum loading concentration of rGO (0.75 wt %), the sensor shows the maximum sensing response of ∼63.8% for 100 ppm hydrogen at moderate operating temperature (150 °C). The rGO-loaded sensors were able to detect a minimum of 1 ppm hydrogen concentration and showed high selectivity. However, a further increase in the rGO concentration (1.5 wt %) leads to the reduction of the relative response of hydrogen gas, ascribed to the formation of interconnections of rGO between electrodes. Therefore, it reduces the total resistance of the sensor and minimizes the effect of p-n heterojunction on sensor response.

Original languageEnglish (US)
Pages (from-to)11116-11124
Number of pages9
JournalACS Applied Materials and Interfaces
Volume10
Issue number13
DOIs
StatePublished - Apr 4 2018
Externally publishedYes

Keywords

  • hydrogen
  • p-n heterojunction
  • RF sputtering
  • rGO-loaded Ni-doped ZnO nanostructures
  • selectivity

ASJC Scopus subject areas

  • Materials Science(all)

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