Electrodeposition of tantalum on carbon black in non-aqueous solution and its electrocatalytic properties

• We electrodeposited Ta nanoclusters (Ta/CB/GC) in acetonitrile at room temperature.
• The Ta/CB/GC showed better or comparable performance to bare Pt for ORR.
• The Ta/CB/GC showed high sensitivity for reduction of hydrogen peroxide at pH 7.4.
• The Ta/CB/GC showed possible simultaneous detection of ascorbic acid and dopamine.
• We extended the applicability of Ta electrode material for various electrocatalytic reactions.

In this work, we synthesized tantalum (Ta) nanoclusters on carbon black (Ta/CB) via simple electrodeposition in non-aqueous solvent, acetonitrile (ACN) at ambient temperature. Transmission electron microscopy (TEM) images showed that the electrodeposited Ta nanoclusters consisted of tiny Ta nanoparticles. X-ray photoelectron spectroscopy (XPS) result represented that the outermost Ta formed the native oxide on Ta/CB due to its ambient exposure to air. Electrochemical catalytic properties of prepared Ta/CB on glassy carbon electrode (Ta/CB/GC) were investigated toward reductions of oxygen and hydrogen peroxide, and oxidations of ascorbic acid and dopamine. For oxygen reduction reaction (ORR) in acid, Ta/CB/GC represented a decent electrocatalytic performance which was better or comparable to bare Pt. The operational stability in acidic condition was maintained up to 500 repetitive potential cycles presumably due to the protective native Ta oxide layer. Ta/CB/GC also showed high amperometric sensitivity (4.5 (±0.16) mA mM−1 cm−2, n = 5) for reduction of hydrogen peroxide in 0.1 M phosphate buffer solution (PBS, pH 7.4). In addition, Ta/CB/GC was demonstrated for the possibility of simultaneous detection of ascorbic acid and dopamine using differential pulse voltammetry (DPV).

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