Electrodes of synthetic diamond: The effects of Ti substrate pretreatment on the electrode properties

Abstract

The electrode properties of boron-doped diamond thin films grown on Ti substrates by a hot-filament chemical vapor deposition technique are evaluated. The Ti substrate surface modifying conditions are devised, involving the surface roughening, annealing, and etching, which effectively improve the diamond electrode properties. The preetching of the Ti substrate produces the titanium hydride layer that can affect the borondoped diamond film growth significantly. The substrate roughened surface obviously improved the diamond film adhesion and reduced the inner stress. The electrodes reveal minimal background current and better stability. A wider potential window, up to ~3 V, is observed for the boron-doped diamond on the etched/annealed samples. The electrochemical activity of the electrodes in the Fe ( CN redox system somewhat increases with increasing surface roughness. The apparent increase in the reversibility of the reaction may be explained by the decrease in the true current density. Suitability of the Ti-based boron-doped diamond electrodes for electroanalytical applications is exemplified by sensing the trace metal ions, such as Hg 2+ and Pb 2+ .

Conductive-Matrix-Mediated Alkaline Fe(III/VI) Charge Transfer: Three-Electron Storage, Reversible Super-Iron Thin Film Cathodes

“…Various titanium substrate pretreatment methods were investigated, as a 10-fold increase in titanium surface area had been reported by pretreatment. 30 Although we observe an enhancement, albeit smaller than reported, of normalized electroactivity upon annealing or chemical etching of the titanium, this enhancement was not evident when these pretreated surfaces were platinized. Hence, only a factor of 1.5-2.5 increase in normalized electroactivity was observed with pretreated Ti (without platinization), and no significant difference was observed when these surfaces were tested for hydrogen evolution, in comparison to untreated Ti when deposited with similar amounts of Pt.…”

“…In addition, we find the electroactive surface morphology of platinized titanium varied with the initial titanium pretreatment, including variations of annealing and chemical etching. Various titanium substrate pretreatment methods were investigated, as a 10-fold increase in titanium surface area had been reported by pretreatment …”