Scanning tunneling microscopy of laser-activated carbon electrodes used in studies of electrochemical charge-transfer reactions

Journal Article · · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States)

DOI:https://doi.org/10.1116/1.585503· OSTI ID:5157006

Robinson, R S ^[1]; Sternitzke, K; McCreery, R L ^[2]

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1. Navesink Research and Engineering Center, Red Bank, NJ (United States)
2. Ohio State Univ., Columbus (United States)

Carbon electrodes form the basis of a variety of electroanalytical sensors, in part due to their low cost, wide potential range, and suitability for modification. A major research effort is underway in many laboratories to understand better the properties of carbon electrodes regarding electrocatalytic activity and other factors such as background current and electron transfer activity. One method of improving the performance of these electrode materials involves the application of pulses from a Nd:YAG or N{sub 2} laser, either during or prior to electrochemical use. Both electrochemical and spectroscopic probes indicate dramatic changes to the surface of the electrodes after the pulses. Raman spectroscopy of the electrode surface indicates damage to the carbon lattice, with an increase in intensity of the Raman band at 1360 cm{sup {minus}1}. Mechanisms of electrode activation by the laser pulses can involve roughening of the electrode surface, or ablation or cleaning of the electrode. This paper reports on scanning tunneling microscope (STM) images of graphite and glassy carbon surfaces before and after delivery of laser pulses of various energies which show a roughening of the surface from the laser treatment, with the appearance of new features of submicron size. The graphite electrodes show a highly disrupted surface, with jagged features and high roughness factors, determined from the STM images. None of the types of features observed in the laser-activated regions of graphite electrodes have been previously observed in our laboratory, in the course of dozens of experiments involving the imaging of different samples and grades of fresh or mechanically damaged graphite electrodes.

• OSTI ID: 5157006
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States), Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States) Vol. 9:2; ISSN 0734-211X; ISSN JVTBD
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
ABLATION
CARBON
CHEMISTRY
ELECTROCHEMISTRY
ELECTRODES
ELECTROMAGNETIC RADIATION
ELEMENTS
LASER RADIATION
MATHEMATICS
MICROSCOPY
NONMETALS
PERFORMANCE
RADIATIONS
ROUGHNESS
SURFACE PROPERTIES
TOPOLOGY
TUNNEL EFFECT