Microcrystalline diamond electrodes

FIG. 12. Cyclic voltammetric i-E curves for a boron-doped microcrystalline diamond electrode in 1 mM ascorbic acid + 0.1 M HCIO4 before, after anodic polarization at different potentials, and after rehydrogenation in a hydrogen plasma. 

Muna, G. W., Tasheva, N. and Swain, G. M. (2004), Electro-oxidation and amperometric detection of chlorinated phenols at boron-doped diamond electrodes A comparison of microcrystalline and nanocrystalline thin films. Environ. Sci. Technol., 38(13) 3674-3682. 

BDD electrodes are semiconductor electrodes with microcrystalline structure and relatively rough surfaces on the micrometric scale. Diamond-coated electrodes used for disinfection are chemically, mechanically, and thermally very resistant and show very low corrosion even under high electric charge. Diamond electrodes present no surface redox processes as known from other carbon electrodes (for example glassy carbon). 

Most of the published work with diamond electrodes has involved the use of microcrystalline films [19,22,26-128]. Material characterization for the purpose of verifying film quality is an important component of any... 

FIG. 9. Background cyclic voltammetric i-E curves for (a) glassy carbon, (b) a moderately boron-doped microcrystalline diamond film electrode, and (c) a heavily boron-doped microcrystalline diamond film electrode in 0.1 M HCIO4. Electrode area = 0.2 cm. Scan rate = 0.1 V/s. 

Ru(NH3)6, 0.1 mM IrClg, and 0.05 mM methyl viologen (MV ) at a boron-doped microcrystalline diamond thin-film electrode. Scan rate = 0.1 V/s. Electrolyte = 1 M KCl. 

Cyclic Voltammetric and Heterogeneous Electron Transfer Rate Constant Data for Four Aqueous-Based Redox Systems at Boron-Doped Microcrystalline Diamond Thin-Film Electrodes... 

One important electrochemical technology where diamond electrodes have made a significant impact is in the area of electroanalysis. CVD diamond offers advantages over other electrodes, especially sp carbon (e.g., glassy carbon), in terms of linear dynamic range, limit of detection, response time, response precision, and response stability. Some of the reported applications of diamond in electroanalysis are highlighted below. Unless stated otherwise, all the diamond electrodes mentioned below are boron-doped, microcrystalline thin films deposited on a conducting substrate (e.g.. Si). 

FIG. 23. Transmission spectra for different materials in the (A) UV/Vis and (B) IR regions of the electromagnetic spectrum. The electrodes in (A) are (1) a thin film of ITO on quartz, (2) a thin film of boron-doped nanocrystalline diamond on quartz, (3) a thin film of mechanically polished and boron-doped diamond on an optically pure, white diamond substrate, and (4) a free-standing, boron-doped, and mechanically polished diamond disc. The electrodes in (B) are (5) an optically pure and mechanically polished white diamond disc, (6) an undoped and polished (both sides) Si substrate, and (7 and 8) moderately and heavily boron-doped microcrystalline diamond thin films deposited on the undoped Si. (Reprinted with permission from Interface 2003, 12, 33. Copyright (2003) The Electrochemical Society, Inc.) (From Ref. 158.)... 

Diamond OTEs are also useful for studying the electrochemical and optical properties of important biomolecules, like cytochrome c. We recently reported that boron-doped microcrystalline diamond thin film electrodes are quite responsive for horse heart cytochrome c, exhibiting a very active and stable cyclic voltammetric response without any pretreatment or surface modification [119,124]. Heterogeneous electron-transfer... 

Haymond, S., Babcock, G.T. and Swain, G.M. (2003) Electron transfer kinetics of ferrocene at microcrystalline boron-doped diamond electrodes effect of solvent and electrolyte. Electroanalysis, 15,249. 

CCL-Diamond, http //www.ccl diamond.com/HTML/Products Electrodes.html Microcrystalline thin-film BDD electrodes Coated on Ti, W, Mb, Si... 

Fig. 10 First scan-cyclic voltammetric i—E curves for the reduction of 4-nitrophenyl diazonium tetrafluoroborate at microcrystalline and nanocrystalline diamond thin-film electrodes. Scan rate = 100 mV s h...

IV. CHARACTERIZATION OF MICROCRYSTALLINE AND NANOCRYSTALLINE DIAMOND THIN FILM ELECTRODES... 

Cyclic voltammetric measurements were made using well-characterized microcrystalline, boron-doped diamond thin-film electrodes to test the material s responsiveness for ferrocene as a function of scan rate, solvent. 

Figure 8.5 Electron micrograph images of different types of boron-doped diamond (BDD) electrodes showing (A) microcrystalline flat BDD film, (B) a CNT/BDD teepee matrix, (C) a CNT/BDD ridged/honeycomb surface, and (D) higher magnification view of the film in (C). (Reproduced from ref. 37 with the permission of the American Chemical Society.)...

Bennett, J.A., Y. Show, S.H. Wang et al. 2005. Pulsed galvanostatic deposition of Pt particles on microcrystalline and nanocrystalline diamond thin-film electrodes. Journal of Electrochemical Society 152 E184-E192. 

---