Tunneling Mode of Scanning Electrochemical Microscopy (SECM): Probing Electrochemical Processes at Single Nanoparticles.

Tunneling Mode of Scanning Electrochemical Microscopy (SECM): Probing Electrochemical Processes at Single Nanoparticles. Angew Chem Int Ed Engl. 2018 Apr 16;: Authors: Sun T, Wang D, Mirkin MV Abstract Electrochemical experiments at individual nanoparticles (NP) can provide new insights into their structure-activity relationships. By using small nanoelectrodes as tips in the scanning electrochemical microscope (SECM), we recently imaged individual surface-bound 10-50 nm metal NPs. Herein, we introduce a new mode of the 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 ≤ ~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 methodology should be useful for studying the effects of nanoparticle size and geometry on electrocatalytic activity in real-world application environment. PMID: 29663600 [PubMed - as supplied by publisher]
Source: Angewandte Chemie - Category: Chemistry Authors: Tags: Angew Chem Int Ed Engl Source Type: research