Scan-Rate-Dependent Ion Current Rectification in Bipolar Interfacial Nanopores

Autor: Xiaoling Zhang, Yunjiao Wang, Jiahui Zheng, Chen Yang, Deqiang Wang
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Micromachines, Vol 15, Iss 9, p 1176 (2024)
Druh dokumentu: article
ISSN: 2072-666X
DOI: 10.3390/mi15091176
Popis: This study presents a theoretical investigation into the voltammetric behavior of bipolar interfacial nanopores due to the effect of potential scan rate (1–1000 V/s). Finite element method (FEM) is utilized to explore the current–voltage (I–V) properties of bipolar interfacial nanopores at different bulk salt concentrations. The results demonstrate a strong impact of the scan rate on the I–V response of bipolar interfacial nanopores, particularly at relatively low concentrations. Hysteresis loops are observed in bipolar interfacial nanopores under specific scan rates and potential ranges and divided by a cross-point potential that remains unaffected by the scan rate employed. This indicates that the current in bipolar interfacial nanopores is not just reliant on the bias potential that is imposed but also on the previous conditions within the nanopore, exhibiting history-dependent or memory effects. This scan-rate-dependent current–voltage response is found to be significantly influenced by the length of the nanopore (membrane thickness). Thicker membranes exhibit a more pronounced scan-rate-dependent phenomenon, as the mass transfer of ionic species is slower relative to the potential scan rate. Additionally, unlike conventional bipolar nanopores, the ion current passing through bipolar interfacial nanopores is minimally affected by the membrane thickness, making it easier to detect.
Databáze: Directory of Open Access Journals