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Tunneling Mode of Scanning Electrochemical Microscopy: Probing Electrochemical Processes at Single Nanoparticles
Author(s) -
Sun Tong,
Wang Dengchao,
Mirkin Michael V.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201801115
Subject(s) - scanning tunneling microscope , ohmic contact , scanning electrochemical microscopy , electrochemical scanning tunneling microscope , quantum tunnelling , nanoparticle , materials science , electrochemistry , nanotechnology , electrode , scanning electron microscope , scanning ion conductance microscopy , optoelectronics , scanning tunneling spectroscopy , chemistry , scanning confocal electron microscopy , layer (electronics) , composite material
Electrochemical experiments at individual nanoparticles (NPs) can provide new insights into their structure–activity relationships. By using small nanoelectrodes as tips in a scanning electrochemical microscope (SECM), we recently imaged individual surface‐bound 10–50 nm metal NPs. Herein, we introduce a new mode of SECM operation based on tunneling between the tip and a nanoparticle immobilized on the insulating surface. The obtained current vs. distance curves show the transition from the conventional feedback response to electron tunneling between the tip and the NP at separation distances of less than about 3 nm. In addition to high‐resolution imaging of the NP topography, the tunneling mode enables measurement of the heterogeneous kinetics at a single NP without making an ohmic contact with it. The developed method should be useful for studying the effects of nanoparticle size and geometry on electrocatalytic activity in real‐world applications.