Activity analysis of electrocatalytic water oxidation by trinuclear ruthenium complex on an Au particle matrix

Electrocatalytic water oxidation was carried out using a basal-plane pyroly tic graphite (BPG) electrode coated with electrodeposited Au particles adso rbing Ru-red ([(NH3)(5)Ru-O-Ru(NH3)(4)-O-Ru(NH3)(5)](6+)). The amount of O- 2 evolved, V-O2 (mol h(-1)), increased remarkably by adsorbing the complex onto Au particles. The plots of V-O2 versus the complex amount on Au partic les gave an almost straight line at its: low surface coverage, but deviated downward with an increase in its amount, which is ascribed to the bimolecu lar decomposition. The intrinsic turnover number (TN) of the complex is lar ger than that of the Au particle by three orders of magnitude, The catalyti c activity of the complex was analyzed in terms of its intrinsic TN, k (h(- 1)) and critical decomposition distance, r(d) (nm) based on intermolecular distance distribution to obtain k = 21.4 h(-1) and r(d) = 1.11 nm. (C) 1999 Elsevier Science Ltd. All rights reserved.