As one of the important candidate of power sources for the future, the research and production of hydrogen gas has a significant importance. In this article, the emphasis is on the influence of impurities on hydrogen evolution reaction, i.e., the influence of an addition of decacyclene, C(12)H(35)C(6)H(4)SO(4)Na, CH(3)CH(2)OH, chromanone, H(2)SO(4), HNO(3), 4,4'-biphenediol and 1,2,3,4-tetrapheiiyl-1,3-cyclopentadiene was studied by electrochemical impedance technique. The adsorption structure for some organics was measured by scanning tunneling spectroscopy techniques. Superstructure of adsorbed decacyclene on Au(111) surface was captured. The ordered adsorption structure of 4,4'-biphenyldiol on Au(111) and (100) was also observed. The addition of decacyclene has shown an opposite effects on hydrogen evolution for Au(111) and (100) surface, i.e., it inhibits the reaction at Au(100) but enhances the one at Au(111). The results show that the addition Of C(12)H(35)C(6)H(4)SO(4)Na and HNO(3), especially the latter, can improve the hydrogen evolution. In the article the adsorption structure and hydrogen evolution reaction have been studied in order to give some useful information about the relation between the adsorption structure and the properties. The purpose of this article is to attempt to find the relation between electrochemical performance and the adsorption structure, and to explore the effect of some additives. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.