Preparation and Electrochemical Characterization of Carbon Paper Modified with a Layer of Boron-Doped Nanocrystalline Diamond

Abstract

Carbon paper ͑CP͒ was modified with a layer of boron-doped nanocrystalline diamond ͑BND͒ in order to improve the material's chemical resistance and microstructural stability during exposure to aggressive electrochemical environments. In the procedure, carbon fibers in the CP were coated up to a depth of about 50 m with a thin layer ͑ca. 1 m͒ of electrically conducting diamond. The diamond layer was deposited by microwave plasma-assisted chemical vapor deposition using an argon-rich CH 4 /H 2 /Ar/B 2 H 6 source gas mixture. X-ray diffraction and Raman spectroscopy confirmed the presence of a crystalline diamond overlayer. The electrodeposition of Pt electrocatalyst particles was used to probe the electrochemical activity of the diamond-coated electrode. The metal phase was formed using pulsed galvanostatic deposition ͑cathodic͒ at 1.25 mA/cm 2 ͑geom.͒ and evaluated in terms of ͑i͒ the particle size and distribution, ͑ii͒ the stability during anodic polarization, and ͑iii͒ the electrochemical activity for the reduction of dissolved oxygen. Pt particles with a diameter of 100-300 nm and a particle density of 10 8 -10 9 cm −2 were formed on all regions of the BND electrode. Importantly, the diamond-modified electrode exhibited superior morphological and microstructural stability during anodic polarization ͑1.4 V vs Ag/AgCl͒ as compared to CP, both in the presence and absence of Pt. The results demonstrate that surface modification with electrically conducting diamond is a means to improve the dimensional stability of sp 2 carbon materials, particularly those used in fuel cells.

Stability Enhancement of Pd Catalysts by Compositing with Polypyrrole Layer for Polymer Electrolyte Fuel Cell Electrodes

“…The discrepancy between XPS and XRD indicates that the dominant phase is metallic Pd regardless of the PPy modification, but there is substantial amount of higher valence Pd species on the surface layer in the case of Pd-PPy catalyst. Other XRD spectrum for carbon paper is assigned by the diffraction peaks expected for sp2-bonded carbon at 2h = 42.9°(1 0 0), 2h = 54.6°(0 0 4) and 2h = 77.8°(1 1 0) planes [24]. The issue of durability is one of the most important factors for the PEMFC fuel cell catalyst.…”

Thin‐Layer and Wall‐Jet Arrangement of Amperometric Detector with Boron‐Doped Diamond Electrode: Comparison of Amperometric Determination of Aminobiphenyls in HPLC‐ED

“…Assuming a 25 % compression of the gasket when the two pieces of the cell were clamped together, the cell volume was estimated to be~10 mL. The microcrystalline BDD film electrode deposited on silica wafers was prepared and characterized by procedures described earlier [44] at Michigan State University, East Lansing, MI, USA. The surface of BDD electrodes was oxidized in 0.1 mol L À1 H 2 SO 4 by applying the potential of + 2.4 V (vs. SSCE) for 60 min prior the first usage.…”

A Transmission Electron Microscopy Study of Degradation Mechanisms in a Tin-Carbon Fibre Composite Anode for Rechargeable Lithium-Ion Batteries

“…The presence of the D band and the peak intensity ratio, I D /I G , indicated that the as-received CFP had microstructural disorder, possibly due to the presence of exposed edge planes along each fibre (33). The charge-discharge cycling increased the I D /I G ratio from 0.19 to 0.36, indicating that additional structural damage was inducted into the carbon fibres during electrochemical cycling (34,35).…”