Scanning Electrochemical Microscopy Featuring Transient Current Signals in Carbon Nanopipets with Dilute or No Redox
Yingfei Ma1, Yingjie Zhao1, Rujia Liu1
1Department of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
Abstract:
Herein, we report a sensitive scanning electrochemical microscopy (SECM) method based on the high transient current signals in carbon nanopipets (CNPs) under step potential waveforms. Taking advantage of the transient peak current, the approach curve can be conducted with very dilute (1 μM) or even no redox mediator and fitted by the scanning ion conductance microscopy (SICM) theory. In addition, a trace amount of electroactive species generated at the substrate can also be directly revealed from the transient current at the CNP tips. With the established feedback and generation/collection methods, we present the constant-height topography and electroactivity imaging of the substrates with only 1 μM K4Fe(CN)6. The developed new SECM method would allow the usage of CNPs to achieve both high sensitivity and spatial resolution with dilute or no redox mediator and thus find great potential applications in biological and electrocatalytic studies.
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