CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions

The paper presents the possibility of detecting low H<sub>2</sub>S concentrations using CuWO<sub>4</sub>. The applicative challenge was to obtain sensitivity, selectivity, short response time, and full recovery at a low operating temperature under in-field atmosphere, which m...

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Main Authors: Simona Somacescu, Adelina Stanoiu, Ion Viorel Dinu, Jose Maria Calderon-Moreno, Ovidiu G. Florea, Mihaela Florea, Petre Osiceanu, Cristian E. Simion
Format: Article
Language:English
Published: MDPI AG 2021-01-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/14/2/465
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spelling doaj-20353b184c504346bb7dc2e292c1598f2021-01-20T00:05:20ZengMDPI AGMaterials1996-19442021-01-011446546510.3390/ma14020465CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field ConditionsSimona Somacescu0Adelina Stanoiu1Ion Viorel Dinu2Jose Maria Calderon-Moreno3Ovidiu G. Florea4Mihaela Florea5Petre Osiceanu6Cristian E. Simion7“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaThe paper presents the possibility of detecting low H<sub>2</sub>S concentrations using CuWO<sub>4</sub>. The applicative challenge was to obtain sensitivity, selectivity, short response time, and full recovery at a low operating temperature under in-field atmosphere, which means variable relative humidity (%RH). Three different chemical synthesis routes were used for obtaining the samples labeled as: CuW1, CuW2, and CuW3. The materials have been fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). While CuWO<sub>4</sub> is the common main phase with triclinic symmetry, different native layers of CuO and Cu(OH)<sub>2</sub> have been identified on top of the surfaces. The differences induced into their structural, morphological, and surface chemistry revealed different degrees of surface hydroxylation. Knowing the poisonous effect of H<sub>2</sub>S, the sensing properties evaluation allowed the CuW2 selection based on its specific surface recovery upon gas exposure. Simultaneous electrical resistance and work function measurements confirmed the weak influence of moisture over the sensing properties of CuW2, due to the pronounced Cu(OH)<sub>2</sub> native surface layer, as shown by XPS investigations. Moreover, the experimental results obtained at 150 °C highlight the linear sensor signal for CuW2 in the range of 1 to 10 ppm H<sub>2</sub>S concentrations and a pronounced selectivity towards CO, CH<sub>4</sub>, NH<sub>3</sub>, SO<sub>2</sub>, and NO<sub>2</sub>. Therefore, the applicative potential deserves to be noted. The study has been completed by a theoretical approach aiming to link the experimental findings with the CuW2 intrinsic properties.https://www.mdpi.com/1996-1944/14/2/465CuWO<sub>4</sub>surface hydroxylationselective sensitivity to H<sub>2</sub>Sapplicative potential under in-field conditionstheoretical approach
collection DOAJ
language English
format Article
sources DOAJ
author Simona Somacescu
Adelina Stanoiu
Ion Viorel Dinu
Jose Maria Calderon-Moreno
Ovidiu G. Florea
Mihaela Florea
Petre Osiceanu
Cristian E. Simion
spellingShingle Simona Somacescu
Adelina Stanoiu
Ion Viorel Dinu
Jose Maria Calderon-Moreno
Ovidiu G. Florea
Mihaela Florea
Petre Osiceanu
Cristian E. Simion
CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
Materials
CuWO<sub>4</sub>
surface hydroxylation
selective sensitivity to H<sub>2</sub>S
applicative potential under in-field conditions
theoretical approach
author_facet Simona Somacescu
Adelina Stanoiu
Ion Viorel Dinu
Jose Maria Calderon-Moreno
Ovidiu G. Florea
Mihaela Florea
Petre Osiceanu
Cristian E. Simion
author_sort Simona Somacescu
title CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
title_short CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
title_full CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
title_fullStr CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
title_full_unstemmed CuWO<sub>4</sub> with CuO and Cu(OH)<sub>2</sub> Native Surface Layers for H<sub>2</sub>S Detection under in-Field Conditions
title_sort cuwo<sub>4</sub> with cuo and cu(oh)<sub>2</sub> native surface layers for h<sub>2</sub>s detection under in-field conditions
publisher MDPI AG
series Materials
issn 1996-1944
publishDate 2021-01-01
description The paper presents the possibility of detecting low H<sub>2</sub>S concentrations using CuWO<sub>4</sub>. The applicative challenge was to obtain sensitivity, selectivity, short response time, and full recovery at a low operating temperature under in-field atmosphere, which means variable relative humidity (%RH). Three different chemical synthesis routes were used for obtaining the samples labeled as: CuW1, CuW2, and CuW3. The materials have been fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). While CuWO<sub>4</sub> is the common main phase with triclinic symmetry, different native layers of CuO and Cu(OH)<sub>2</sub> have been identified on top of the surfaces. The differences induced into their structural, morphological, and surface chemistry revealed different degrees of surface hydroxylation. Knowing the poisonous effect of H<sub>2</sub>S, the sensing properties evaluation allowed the CuW2 selection based on its specific surface recovery upon gas exposure. Simultaneous electrical resistance and work function measurements confirmed the weak influence of moisture over the sensing properties of CuW2, due to the pronounced Cu(OH)<sub>2</sub> native surface layer, as shown by XPS investigations. Moreover, the experimental results obtained at 150 °C highlight the linear sensor signal for CuW2 in the range of 1 to 10 ppm H<sub>2</sub>S concentrations and a pronounced selectivity towards CO, CH<sub>4</sub>, NH<sub>3</sub>, SO<sub>2</sub>, and NO<sub>2</sub>. Therefore, the applicative potential deserves to be noted. The study has been completed by a theoretical approach aiming to link the experimental findings with the CuW2 intrinsic properties.
topic CuWO<sub>4</sub>
surface hydroxylation
selective sensitivity to H<sub>2</sub>S
applicative potential under in-field conditions
theoretical approach
url https://www.mdpi.com/1996-1944/14/2/465
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