Three-dimensional electrochemical reactions on tip-coated diamond nanowires with nickel nanoparticles

Tip-coated diamond nanowires with nickel nanoparticles (Ni/Dia NW) were applied as a three-dimensional electrode for electrochemical oxidation of glucose and reduction for hydrogen evolution. For glucose oxidation in alkaline solution on Ni/Dia NW, the oxidation potential is 110 mV lower and the oxidation current is 30 times higher than those on a bare diamond electrode. For hydrogen evolution in an acidic solution, the potential (defined as a current density is higher than -0.3 mA cm(-2) at a scan rate of 10 mV s(-1)) reduces from -0.7 V on a bare diamond electrode to -0.2 V (vs. Ag/AgCl) on Ni/Dia NW. These high currents and low overpotentials are probably due to a large electrode area of Ni/Dia NW, a three-dimensional effect, electrocatalytic ability of Ni nanoparticles, and changed mass transport on this electrode. This three-dimensional electrode thus provides a new platform for electrochemical applications. (C) 2012 Elsevier B.V. All rights reserved.