Ni Drastically Modifies the Microstructure and Electrochemistry of Thin Ti and Cr Layers

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-01-25
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Mcode
Degree programme
Language
en
Pages
12
Series
Journal of Physical Chemistry C, Volume 128, issue 3, pp. 1457-1468
Abstract
There is a significant lack of literature addressing changes in the microstructure of different interfacial metal layer combinations employed in fabricating electrochemical sensors based on carbon nanomaterials. This research gap extends to analyzing their influence on the electrochemical performance, which, in turn, impacts the understanding of the properties of materials incorporating these layers. In this study, microstructural variations and electrochemical activity of chromium and titanium adhesion layers, in combination with nickel catalyst layers (designated as TiNi and CrNi), on silicon wafers were analyzed post annealing. Interestingly, during a brief annealing period of 5 min, TiNi developed a surface layer comprising graphitic carbon, alongside the formation of TiO2, TiC, and NiSi, and exhibited electrochemical activity toward both dopamine (DA) and ascorbic acid (AA). Conversely, CrNi annealed for 5 min did not show the presence of such a carbon layer and displayed no discernible electrochemical activity toward the target molecules. Only after an extended annealing time of 20 min, signs of a carbon layer appear on CrNi, displaying a moderate electrochemical activity toward DA and AA. The formation of a carbon layer on CrNi is delayed due to the presence of Ni near the surface, which disrupts the local equilibrium. Consequently, the formation of the Cr2O3 barrier layer is delayed, which in turn permits carbon diffusion into the underlying Cr layer. Conversely, Ni stabilizes the β-Ti form and markedly decreases the solubility of carbon and oxygen within the TiNi system. By providing a comprehensive analysis of microstructural changes and their impact on the surface chemistry and electrochemical responses of commonly used interfacial metal layers, this paper offers invaluable insights in selecting suitable adhesion and catalyst layer combinations for carbon nanomaterial fabrication.
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Publisher Copyright: © 2024 American Chemical Society.
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Citation
Kousar, A, Quliyeva, U, Pande, I, Sainio, J, Julin, J, Sajavaara, T, Jiang, H & Laurila, T 2024, ' Ni Drastically Modifies the Microstructure and Electrochemistry of Thin Ti and Cr Layers ', Journal of Physical Chemistry C, vol. 128, no. 3, pp. 1457-1468 . https://doi.org/10.1021/acs.jpcc.3c07221