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Electrocatalysis of Pd + Au alloy electrodes

1989; Elsevier BV; Volume: 260; Issue: 1 Linguagem: Inglês

10.1016/0022-0728(89)87109-8

2590-2954

Katsunori Nishimura, Keiji Kunimatsu, Ken‐ichi Machida, Michio Enyo,

Catalysis and Oxidation Reactions

The formation of a bridge-type adsorbed CO species during the electro-oxidation of formaldehyde on Pd+Au alloy electrodes, but not on a Au electrode, in alkaline media was investigated by means of infrared reflectance spectroscopy. The CO species is probably formed from HCHO which is predominant in the solution at lower pH, but not from HOCH2O−. The species acts as a catalytic poison in formaldehyde electro-oxidation, but the effect is weaker at higher pH where oxidation of HOCH2O− takes place more readily. The rate of CO formation is faster at lower pH and on electrodes of higher Pd content. No CO species was detected in the HCOO− system. In mixed solutions of HCOO− and HCHO, the oxidation of formate on both Pd and Pd+Au alloy electrodes is suppressed greatly by the CO species originating from HCHO. The poisoning effect becomes less pronounced on the alloy electrodes of higher Au content.