Copper oxide based H2S dosimeters – Modeling of percolation and diffusion processes

Hennemann, Jörg; Kohl, Claus-Dieter; Smarsly, Bernd M.; Metelmann, Hauke; Rohnke, Marcus; Janek, Jürgen; Reppin, Daniel; Meyer, B. K.; Russ, Stefanie; Wagner, Thorsten

doi:10.1016/j.snb.2015.02.001

Cited by 39 publications

(45 citation statements)

References 33 publications

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“…For regeneration, only a heater has to be controlled and the trigger time can be directly correlated with the H 2 S dose (concentration × time). CuO thin films detect quite low doses (∼ 10 ppm × 15 min) which are in the same range as supposed working limits (Hennemann et al, 2015a;IFA, 2016).…”

Section: Introductionsupporting

confidence: 64%

“…However, in spite of these encouraging results, the impact of several parameters needs to be understood in more detail. For example, copper oxide can be a mixture of different species, in particular CuO, Cu 2 O and also Cu 4 O 3 , created either due to reducing conditions during the synthesis or by reducing gases during operation at elevated temperatures (Hennemann et al, 2015a). As discussed in previous works (Sharma, 1980) the reaction mechanism of Cu 2 O in a H 2 S-containing atmosphere is still not understood in detail.…”

Section: Introductionmentioning

confidence: 97%

“…Several works have already shown the principal suitability of CuO in H 2 S sensors, but the lifetime and precision are currently substantial problems to overcome (Hennemann et al, 2015a, b;Kneer et al, 2016). Since biogas represents a mixture of many gases containing only minor amounts of H 2 S, the sensors should be insensitive to other reducing gases being present in such mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…As discussed in previous works (Sharma, 1980) the reaction mechanism of Cu 2 O in a H 2 S-containing atmosphere is still not understood in detail. For instance, the role of diffusion effects in the percolation regime reaction of Cu 2 O films with H 2 S is not clear yet; see the discussion in the study of Hennemann et al (2015a). Also, Sharma (1980) noted that the reactivity of Cu 2 O towards H 2 S can strongly depend on the humidity (Sharma, 1980).…”

Section: Introductionmentioning

confidence: 99%

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H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

Seitz

Beck

Hennemann

et al. 2017

J. Sens. Sens. Syst.

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Abstract.Copper oxides, such as CuO and Cu 2 O, are promising materials for H 2 S detection because of the reversible reaction with H 2 S to copper sulfides (CuS, Cu 2 S). Along with the phase change, the electrical conductance increases by several orders of magnitude. On CuO x films the H 2 S reaction causes the formation of statistically distributed Cu x S islands. Continuous exposition to H 2 S leads to island growth and eventually to the formation of an electrical highly conductive path traversing the entire system: the so-called percolation path. The associated CuO x / Cu x S conversion ratio is referred to as the percolation threshold. This pronounced threshold causes a gas concentration dependent switch-like behaviour of the film conductance. However, to utilize this effect for the preparation of CuO-based H 2 S sensors, a profound understanding of the operational and morphological parameters influencing the CuS path evolution is needed.Thus, this article is focused on basic features of H 2 S detection by copper oxide films and the influence of structural parameters on the percolation threshold and switching behaviour. In particular, two important factors, namely the stoichiometry of copper oxides (CuO, Cu 2 O and Cu 4 O 3 ) and surface morphology, are investigated in detail. CuO x thin films were synthesized by a radio frequency magnetron sputtering process which allows modification of these parameters. It could be shown that, for instance, the impact on the switching behaviour is dominated by morphology rather than stoichiometry of copper oxide.

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Section: Introductionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

Seitz

Beck

Hennemann

et al. 2017

J. Sens. Sens. Syst.

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“…Formation of the CuS on the CuO has been proven by the XPS analysis results. 43,44 CuS, a metallic-like conductor, will increase the connectivity between the neighboring CuO sheets, leading to a decrease of the resistance of the CuO nanosheets film. The porous CuO nanosheets are convenient for the adsorption of the H 2 S gas molecules, thus facilitating the transformation of CuS.…”

Section: Gas-sensing Mechanismmentioning

confidence: 99%

Room-Temperature High-Performance H₂S Sensor Based on Porous CuO Nanosheets Prepared by Hydrothermal Method

Wang

Lin

et al. 2016

ACS Appl. Mater. Interfaces

228

109

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Porous CuO nanosheets were prepared on alumina tubes using a facile hydrothermal method, and their morphology, microstructure and gas sensing properties were investigated. The monoclinic CuO nanosheets had an average thickness of 62.5 nm and were embedded with numerous holes with diameters ranging 5 nm to 17 nm. The porous CuO nanosheets were used to fabricate gas sensors to detect hydrogen sulfide (H 2 S) operated at room temperature. The sensor showed a good response sensitivity of 1.25 with the respond/recovery time of 234 s and 76 s, respectively, when tested with the H 2 S concentrations as low as 10 ppb. It also showed a remarkably high selectivity to the H 2 S, but only minor responses to other gases such as SO 2 , NO, NO 2 , H 2 , CO and C 2 H 5 OH. The working principle of the porous CuO nanosheets based sensor to detect the H 2 S was identified to be the phase transition from semiconducting CuO to a metallic conducting CuS.

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Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H₂S Detection

Paul

Schwind

Weinberger

et al. 2019

Adv Funct Materials

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A nanocomposite material based on copper(II) oxide (CuO) and its utilization as a highly selective and stable gas-responsive electrical switch for hydrogen sulphide (H 2 S) detection is presented. The material can be applied as a sensitive layer for H 2 S monitoring, e.g., in biogas gas plants. CuO nanoparticles are embedded in a rigid, nanoporous silica (SiO 2 ) matrix to form an electrical percolating network of low conducting CuO and, upon exposure to H 2 S, highly conducting copper(II) sulphide (CuS) particles. By steric hindrance due to the silica pore walls, the structure of the network is maintained even though the reversible reaction of CuO to CuS is accompanied by significant volume expansion. The conducting state of the percolating network can be controlled by a variety of parameters, such as temperature, electrode layout, and network topology of the porous silica matrix. The latter means that this new type of sensing material has a structure-encoded detection limit for H 2 S, which offers new application opportunities. The fabrication process of the mesoporous CuO@SiO 2 composite as well as the sensor design and characteristics are described in detail. In addition, theoretical modeling of the percolation effect by Monte-Carlo simulations yields deeper insight into the underlying percolation mechanism and the observed response characteristics.

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Copper oxide based H2S dosimeters – Modeling of percolation and diffusion processes

Cited by 39 publications

References 33 publications

H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

Room-Temperature High-Performance H₂S Sensor Based on Porous CuO Nanosheets Prepared by Hydrothermal Method

Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H₂S Detection

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Copper oxide based H2S dosimeters – Modeling of percolation and diffusion processes

Cited by 39 publications

References 33 publications

H&lt;sub&gt;2&lt;/sub&gt;S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

H&lt;sub&gt;2&lt;/sub&gt;S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

Room-Temperature High-Performance H2S Sensor Based on Porous CuO Nanosheets Prepared by Hydrothermal Method

Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H2S Detection

Contact Info

Product

Resources

About

H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

H<sub>2</sub>S dosimeter with controllable percolation threshold based on semi-conducting copper oxide thin films

Room-Temperature High-Performance H₂S Sensor Based on Porous CuO Nanosheets Prepared by Hydrothermal Method

Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H₂S Detection