On the electrochemical behavior of H2O2 AT Ag in alkaline solution

✍ Scribed by Masataka Honda; Takuro Kodera; Hideaki Kita

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 595 KB
• Volume: 28
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(83)85073-7

✦ Synopsis

Etectrochemical oxidation and reduction of H,O, on Ag were studied in alkaline solution of lo-'4.3 M H,O, and 2 x lo-'-1.0 M KOH under N2 bubbling. Steady i-4 cwves obtained by a cyclic potential sweep method in a potential range where no electrode oxidation takes place, lead to the following results: (1) is (Acm-*) (cathodic limiting current density) = 1.0 x [H202];" (M], (2) ia (Acm-') (anodic limiting one) = i:([KOH] B [H,O,]=) or 1.0 x [KOH]L~o (M) ([KOH] < [H,O,],). (3) 4, (V) (mixed potential) = O.L26&.060 10g[K0H]'~~ and (4) (a&/&)+ _ .+m ( Rcm2) (reaction resistance at @ = $,) = 0.057 x [H,O&',* (M-l), where [H2021T designates a total H,O* concentration and the others have their usual meanings. The above results are explained by the following mechanism, HO; formed by the reversible chemical reaction, H,02 -t OH-+ HO; fH,O, is oxidised in anodic reaction by two steps: HO; AHO, +e-and HO,(a)+OH-+O,+H,O+e-, whereas in cathodic reaction, H,O, is reduced by H,O, +e-_PrzOH(a) +OH-, OH(a)+e--+ OH-. Here, + designates a rate determining step. Catalytic decomposition of H,Oz on the electrode is also discussed.