Serhiy Cherevko

The porous CuO electrode fabricated by hydrogen bubble evolution and its application to highly sensitive non-enzymatic glucose detection

The porous Cu film was deposited on a Pt/Ti/Si substrate by electrochemical deposition accompanied by hydrogen evolution at very high current densities. CuO films with similar morphologies were obtained by subsequent annealing of the porous copper films. The morphology, composition and structure of the porous Cu and porous CuO were investigated by FE-SEM, EDS and XRD methods. The complete transformation of Cu to CuO after annealing was indicated. The sensing performances of the porous CuO film were evaluated in alkaline solution with the porous CuO film showing a wide linearity range from 1microM to 2.5mM with sensitivity of 2.9mAcm(-2)mM(-1), and detection limit of 0.14microM. The sensor showed good selectivity to conventional intermediates such as AA and UA and long term stability.

Nanoporous Pt@Au(x)Cu(100-x) by hydrogen evolution assisted electrodeposition of Au(x)Cu(100-x) and galvanic replacement of Cu with Pt: electrocatalytic properties.

Electrodeposition of high-surface-area nanoporous Au-Cu foams under conditions of hydrogen codeposition is studied. The honeycomb-like Au(x)Cu(100-x) foams with 0 ≤ x ≤ 100 are electrodeposited by controlling the amount of corresponding ions in the solution. The amount of metal ions in deposited films follows that in used electrolytes. Compared to monometallic foams, the Au(x)Cu(100-x) structures are characterized by smaller ligament or particle sizes (less than 10 nm) and improved stability. The addition of even a small amount of Cu to the Au matrix is found to dramatically improve the stability of the structure in air environment or an acidic medium. Pt@Au(x)Cu(100-x) structures are formed by the galvanic displacement of Cu from Au(x)Cu(100-x) templates. During the displacement of Cu by Pt, Au serves as a buffer, decreasing mechanical stresses and preventing the detachment of the foam from the substrate. The surface ratio of Pt to Au atoms is controlled by adjusting the amount of Cu in the template. Pt@Au(x)Cu(100-x) electrodes are investigated as novel electrocatalysts for methanol oxidation in alkaline media. The Au-enriched surfaces show higher catalytic activity toward methanol oxidation, while the electrodes with a higher amount of Pt are more stable.

Formation of nanoporous nickel oxides for supercapacitors prepared by electrodeposition with hydrogen evolution reaction and electrochemical dealloying

Highly nanoporous nickel oxide electrodes were obtained by electrodeposition accompanied by hydrogen evolution reaction and the selective electrochemical dealloying of copper from Ni-(Cu) porous foam. The nanoporous nickel oxide electrodes consequently have numerous dendritic morphologies composed of nanopores with 20–30 nm diameters. The specific capacitances were 428 F g−1 for as-deposited Ni-(Cu) foam electrode and 1,305 F g−1 for nanoporous nickel-oxide electrode after dealloying process, respectively. This indicates increased surface area by dealloying process leads to innovative increase of specific capacitance.

α-MoO3 nanowire-based amperometric biosensor for l-lactate detection

Large-scale orthorhombic single-crystalline molybdenum trioxide nanowires were synthesized using a facile one-pot hydrothermal method. Lactate oxidase enzyme was immobilized on the nanowires to produce a highly sensitive electrochemical biosensor for l-lactate detection. At an applied potential of 0.5xa0V, the sensor exhibited a high sensitivity of 0.87xa0μA/mM with a fast response to l-lactate (90% of response times within 10xa0s). A linear response was obtained over a concentration range from 0.5 to 8xa0mM with a detection limit of 0.15xa0mM (S/Nu2009=u20093). The developed biosensor showed excellent reproducibility and operational stability, as well as the ability to be stored long term.