A solution supersaturated with hydrogen obtained by water electrolysis was studied using cyclic voltammetry. The cyclic voltammogram of the solution supersaturated with hydrogen gave a peak Current at -0.1 V vs. Ag vertical bar AgCl. No peak current in a solution saturated with hydrogen was observed by bubbling hydrogen gas through the solution. The peak current was influenced by the temperature and ion type of the electrolyte. The peak current was found to be due to the presence of hydrogen nanobubbles. The peak current increased with increasing hydrogen nanobubble concentration and decreased to zero within 3 h after electrolysis. (c) 2006 Elsevier B.V. All rights reserved.