Design Rules for Nanogap‐Based Hydrogen Gas Sensors

Lee, Junmin; Shim, Wooyoung; Noh, Jin−Seo; Lee, Wooyoung

doi:10.1002/cphc.201200014

Cited by 59 publications

(42 citation statements)

References 84 publications

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“…Furthermore, the metal film consisting of electroplated Pd NPs is predicted to maintain its intrinsic properties for H 2 gas sensor upon volume expansion of Pd to Pd:H. The proposed H 2 sensor based on Pd on n + -Si/SiO 2 -NH 2 -AuNP requires extremely low power and costs less owing to much simpler and reproducible fabrication than ever, i.e. transfer process of Pd to insulator substrate, [22][23][24] etching of photoresist leaving Pd on substrate, [24][25][26] deposition of Pd and SiO 2 on n-GaN layer by co-evaporation, 27 etc. One more thing that is worth to note is that the pro-posed H 2 gas detector shows high performance comparable to other H 2 gas sensors.…”

Section: Resultsmentioning

confidence: 99%

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

Lee

Shin

Lee

et al. 2016

J. Electrochem. Soc.

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Harnessing cathodic hydrogen atom generation, metals such as Pt, Pd, Cu, Au and Ni are directly electrodeposited on functionalized dielectric layers of 6 nm thick silicon oxide formed by thermal oxidation of c-Si substrate. Modifying the oxide layer with functional molecules and Au nanoparticles by simple wet chemistry, we can enhance electrodeposition efficiently and thereby electroplate nanoparticles of Pd and Pt to obtain such thin metal films. In particular, Au nanoparticles on amine-modified silicon oxides remarkably enhance electrodeposition of metal nanoparticles to create sturdy metal films on the dielectric layer, n + -Si/SiO 2 -NH 2 . Such enhancement is ascribed to good affinity of Au nanoparticles with electrodeposited metal as well as enhanced current density across the silicon oxide. For an example of potential applications, we show one-step electrodeposition Pd film on dielectric layers to fabricate conductometric hydrogen gas sensor without transferring Pd film. 8 and so on. Electrochemical methods 9,10 allow the solution process under fine and easy control without reducing agents by directly delivering electrons to precursors. Importantly, it can create stabilizer-free NPs or films with pristine surfaces that potentially serve as catalytically active sites for sensors and chemical reactions.11 Therefore, electroplating method has been widely considered as a cost-effective alternative. Especially, electro-synthesis of nanoparticles on conducting surfaces 12,13 has been attracting steady attention as highlighted by shape-control of nanoparticles using the programmed electrochemical methods on glassy carbon electrode. 14 Despite its valuable merits, programmed electro-synthesis can produce nanoparticles on the conducting electrode, while need to be transferred to other substrates, mostly dielectric materials, for practical applications in many cases. Recently reported strategy gives an inspiration of direct electrodeposition on dielectric layer; Pd NPs deposited on n + -Si/thermal SiO 2 . 15 It appears to be counterintuitive to electroplate on insulating substrates but it works owing to electrogenerated hydrogen (H) atoms in the thermal SiO 2 layer. H atom-mediated electro-reduction on thermal SiO 2 layers can be finely controlled by not only the applied bias but also pH in the solution, producing pristine Pd NPs deposited without any stabilizer or additive. H atoms, which are created by reduction of protons migrating across thermal SiO 2 layers, are expected to make precursors reduced at the interface between SiO 2 and solution. Indeed, this suggests a new breakthrough toward direct electroplating technology for thin metal films on dielectric layer.There are a few critical issues to overcome. Low density of current carried by H atoms and poor affinity of metal onto pristine SiO 2 are likely to make the metal grow too slow to be a film. Furthermore, there is a limitation in uniformity of particles in terms of both size and shape. For fine and steady control of electroplating process, it is undesir...

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Section: Resultsmentioning

confidence: 99%

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

Lee

Shin

Lee

et al. 2016

J. Electrochem. Soc.

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“…Thus, this system enables the single-step electrochemical fabrication of Pd NPs firmly adhered to the SiO 2 layer in aqueous solution at room temperature without surfactants or stabilizers. Pd NPs prepared in this manner are expected to have application in hydrogen storage as catalysts on solid supports and as sensing devices 29 .…”

Section: Resultsmentioning

confidence: 99%

“…Once Pd NPs are formed on the SiO 2 layer, the excess H atoms are predicted to be adsorbed on the surfaces of the Pd NPs spontaneously at room temperature. Even if H 2 molecules are formed, they would be readily dissociated on the Pd surface 29 . Thus, the hydrogen-rich surfaces of the Pd NPs are expected to facilitate deposition of metals, such as Cu, which otherwise do not adhere to the SiO 2 surface 27 .…”

Section: Resultsmentioning

confidence: 99%

Hydrogen-atom-mediated electrochemistry

Lee

et al. 2013

Nat Commun

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“…Among the different metals that can be used for this application, Pd stands as a good option to be included in a H 2 sensor, due to its very good H 2 adsorption and absorption properties and the possibility of forming the metal hydride (PdH x ). The formation of this hydride has been widely reported to be responsible for a very good and reversible performance of the Pd-based H 2 sensors [8,14,15,16]. Pd-based alloys with other metals that present a high affinity for H 2 also appear as a suitable option for these devices, since they would lower the amount of noble metal used and therefore the cost of the device.…”

Section: Introductionmentioning

confidence: 99%

Single wall carbon nanotubes loaded with Pd and NiPd nanoparticles for H2 sensing at room temperature

García-Aguilar

Miguel-García

Berenguer-Murcia

et al. 2014

Carbon

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Pd and bimetallic Ni 50 Pd 50 nanoparticles protected by polyvinylpyrrolidone (PVP) have been synthesized by the reduction-by-solvent method and deposited on single wall carbon nanotubes (SWCNTs) to be tested as H 2 sensors. The SWCNTs were deposited by drop casting from different suspensions. The Pd nanoparticles-based sensors show a very reproducible performance with good sensitivity and very low response times (few seconds) for different H 2 concentrations, ranging from 0.2 to 5 % vol. H 2 in air at atmospheric pressure. The influence of the metal nanoparticle composition, the quality of SWCNTs suspension and the metal loading have been studied, observing that all these parameters play an important role in the H 2 sensor performance. Evidence for water formation during the H 2 detection on Pd nanoparticles has been found, and its repercussion on the behaviour of the assembled sensors is discussed.The sensor preparation procedure detailed in this work has proven to be simple and reproducible to prepare cost-effective and highly efficient H 2 sensors that perform very well under real application conditions. * Corresponding author. Fax: +34 965 903454 E-mail: a.berenguer@ua.es (Á. Berenguer-Murcia) 2 1. Introduction.

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Design Rules for Nanogap‐Based Hydrogen Gas Sensors

Cited by 59 publications

References 84 publications

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

Hydrogen-atom-mediated electrochemistry

Single wall carbon nanotubes loaded with Pd and NiPd nanoparticles for H2 sensing at room temperature

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