Enhanced capacitance of composite TiO₂nanotube/boron-doped diamond electrodes studied by impedance spectroscopy

Abstract

We report on novel composite nanostructures based on boron-doped diamond thin films grown on top of TiO2 nanotubes. The nanostructures made of BDD-modified titania nanotubes showed an increase in activity and performance when used as electrodes in electrochemical environments. The BDD thin films (∼200-500 nm) were deposited using microwave plasma assisted chemical vapor deposition (MW PA CVD) onto anodically fabricated TiO2 nanotube arrays. The influence of boron-doping level, methane admixture and growth time on the performance of the Ti/TiO2/BDD electrode was studied in detail. Scanning electron microscopy (SEM) was applied to investigate the surface morphology and grain size distribution. Moreover, the chemical composition of TiO2/BDD electrodes was investigated by means of micro-Raman spectroscopy. The composite electrodes TiO2/BDD are characterized by a significantly higher capacitive current compared to BDD films deposited directly onto a Ti substrate. The novel composite electrode of TiO2 nanotube arrays overgrown by boron-doped diamond (BDD) immersed in 0.1 M NaNO3 can deliver a specific capacitance of 2.10, 4.79, and 7.46 mF cm(-2) at a scan rate of 10 mV s(-1) for a [B]/[C] ratio of 2k, 5k and 10k, respectively. The substantial improvement of electrochemical performance and the excellent rate capability could be attributed to the synergistic effect of TiO2 treatment in CH4 : H2 plasma and the high electrical conductivity of BDD layers. The analysis of electrochemical impedance spectra using an electric equivalent circuit allowed us to determine the surface area on the basis of the value of constant phase element.

Preparation of TiO2/boron-doped diamond/Ta multilayer films and use as electrode materials for supercapacitors

“…We suggest that the electrolyte ions can migrate into/out of pores in the electrode, with an extended charge-discharge time associated with the reduced scan rate, consistent with previous reports [39]. Table 1 [1,9,20,[40][41][42]. Fig.…”

“…The results show that unlike carbon materials and other metal oxides, TiO 2 capacitors behave as conventional electrical double-layer capacitors via a non-faradic mechanism, and have very low specific capacitances [20]. Siuzdak et al developed a Ti/TiO 2 nanotube/BDD electrode, which provides a capacitance of 7.46 mF cm −2 at a scan rate of 10 mV s −1 [1]. Almeida et al…”

Poly-l-lysine-modified boron-doped diamond electrodes for the amperometric detection of nucleic acid bases

“…Substrates were cleaned by sonication in acetone and 2-propanol for 5 min in each solvent. Next, the substrates were seeded by means of spin-coating in a nanodiamond suspension (crystallite size of 5-10 nm), and spun three times for 60 s at 4000 rpm [51]. The temperature of heating stage was kept at 700°C during the deposition process.…”

Diamond Nanostructures and Nanoparticles: Electrochemical Properties and Applications

“…In 0.1 M NaNO 3 , the specific capacitance of 2.10, 4.79, and 7.46 mF cm , 5000 and 10,000, respectively. The substantial improvement of electrochemical performance and the excellent rate capability was explained with the synergistic effect of TiO 2 treatment in CH 4 :H 2 plasma and the high electrical conductivity of boron-doped diamond layers [50]. Recently, "diamond paper" showed in aqueous electrolyte a capacitance of 0.688 mF cm -2 per layer, or 0.645 F g -1 .…”