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Electrochemical oxidation of HCOONa on Pt in acidic solutions

1987; Elsevier BV; Volume: 220; Issue: 1 Linguagem: Inglês

10.1016/0022-0728(87)88008-7

2590-2954

Hideaki Kita, Tomokatsu Katagiri, Keiji Kunimatsu,

Analytical Chemistry and Sensors

The electrooxidation of HCOONa was carried out over a wide range of pH on Pt. HCOO− and its associated form of HCOOH do not show any difference in electrochemical behaviour. A voltammetric study demonstrates the formation of two kinds of poisoning species in the hydrogen (X1) and double-layer (X2) regions. Their dependences on the potential and pH were examined. Constant polarization measurements give the rate expression, i = k(αH+)−0.43 exp(0.4Fφn/RT), independent of the concentrations of HCOO− and HCOOH. The rate-determining step is concluded to be HCOO− (a) → COO− (a)+H+ + e− or HCOOH(a) → COOH(a)+H+ + e−. The negative reaction order with respect to H+ was explained through the retarding action of X2. The nature of X1 and X2 is discussed.