Back to Search
Start Over
Single-Molecule Electrochemistry on a Porous Silica-Coated Electrode
- Source :
- Journal of the American Chemical Society. 139:2964-2971
- Publication Year :
- 2017
- Publisher :
- American Chemical Society (ACS), 2017.
-
Abstract
- Here we report the direct observation and quantitative analysis of single redox events on a modified indium–tin oxide (ITO) electrode. The key in the observation of single redox events are the use of a fluorogenic redox species and the nanoconfinement and hindered redox diffusion inside 3-nm-diameter silica nanochannels. A simple electrochemical process was used to grow an ultrathin silica film (~100 nm) consisting of highly ordered parallel nanochannels exposing the electrode surface from the bottom. The electrode-supported 3-nm-diameter nanochannels temporally trap fluorescent resorufin molecules resulting in hindered molecular diffusion in the vicinity of the electrode surface. Adsorption, desorption, and heterogeneous redox events of individual resorufin molecules can be studied using total-internal reflection fluorescence (TIRF). The rate constants of adsorption and desorption processes of resorufin were characterized from single-molecule analysis to be (1.73 ± 0.08) × 10−4 cm·s−1 and 15.71 ± 0.76 s−1, respectively. The redox events of resorufin to the non-fluorescent dihydroresorufin were investigated by analyzing the change in surface population of single resorufin molecules with applied potential. The scan-rate-dependent molecular counting results (single-molecule fluorescence voltammetry) indicated a surface-controlled electrochemical kinetics of the resorufin reduction on the modified ITO electrode. This study demonstrates the great potential of mesoporous silica as a useful modification scheme for studying single redox events on a variety of transparent substrates such as ITO electrodes and gold or carbon film coated glass electrodes. The ability to electrochemically grow and transfer mesoporous silica films onto other substrates makes them an attractive material for future studies in spatial heterogeneity of electrocatalytic surfaces.
- Subjects :
- Surface Properties
Inorganic chemistry
Oxide
02 engineering and technology
010402 general chemistry
Electrochemistry
Photochemistry
Indium
01 natural sciences
Biochemistry
Redox
Article
Catalysis
chemistry.chemical_compound
Colloid and Surface Chemistry
Adsorption
Desorption
Particle Size
Electrodes
Molecular diffusion
Total internal reflection fluorescence microscope
Tin Compounds
Electrochemical Techniques
General Chemistry
Silicon Dioxide
021001 nanoscience & nanotechnology
0104 chemical sciences
chemistry
Electrode
0210 nano-technology
Oxidation-Reduction
Porosity
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 139
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi.dedup.....cb666fecaec981432d740f5d6f34ffe7