Amorphous Pd-assisted H 2 detection of ZnO nanorod gas sensor with enhanced sensitivity and stability

Hyeonghun Kim, Yusin Pak, Yeonggyo Jeong, Woochul Kim, Jeongnam Kim, Gun Young Jung

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


For monitoring H2 concentrations in air, diverse resistive gas sensors have been demonstrated. In particular, Pd-decorated metal oxides have shown remarkable selectivity and sensing response for H2 detection. In this work, H2 sensing behavior of amorphous Pd layer covering ZnO nanorods (am-Pd/ZnO NRs) is investigated. This is the first report on the enhanced gas sensing performance attained by using an amorphous metal layer. The amorphous Pd layer is generated by reduction reaction with a strong reducing agent (NaBH4), and it covers the ZnO nanorods completely with a thickness of 2 ∼ 5 nm. For comparison, crystalline Pd nanoparticles-decorated ZnO nanorods (c-Pd/ZnO NRs) are produced using a milder reducing agent like hydrazine. Comparing the c-Pd/ZnO NRs sensor and other previously reported hydrogen sensors based on the crystalline Pd and metal oxides, the am-Pd/ZnO NRs sensor exhibits a remarkable sensing response (12,400% at 2% H2). The enhancement is attributed to complete cover of the amorphous Pd layer on the ZnO NRs, inducing larger interfaces between the Pd and ZnO. In addition, the amorphous Pd layer prevents surface contamination of the ZnO NRs. Therefore, the am-Pd/ZnO NRs sensor maintains initial sensing performance even after 5 months.
Original languageEnglish (US)
Pages (from-to)460-468
Number of pages9
JournalSensors and Actuators B: Chemical
StatePublished - Feb 5 2018

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the by the Small and Medium Business Administration’s 2016 start-up growth technology development project, (No. S2425024) and by the Basic Science Research Program (NRF-2016R1A2B4006395) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education. The research was partially supported by the GIST Research Institute (GRI) project through a grant provided by GIST in 2017. H. Kim is supported by the NRF Grant funded by the Korean Government (NRF-2015-Fostering Core Leaders of the Future Basic Science Program/Global Ph. D. Fellowship Program).


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