Platinum Metals Rev., 1969, 13, (1), 25
Electrochemistry and Heterogeneous Catalysis
A symposium on “Electrocatalysis” was held at the Technological University, Eindhoven, on November 21st and 22nd, and was attended by some 120 people, mainly from continental Europe. The purpose of the meeting was to bring together workers from the fields of electrochemistry and of heterogeneous catalysis for, although both are intimately concerned with the behaviour of surfaces and of adsorbed intermediates, there are all too few opportunities for the exchange of ideas and information in this area. Work performed in recent years on surface morphology at the atomic scale using techniques such as field-emission microscopy and low-energy electron diffraction has greatly influenced thinking about catalysis but seems not to have much influenced electrochemists. Conversely recent work on the mechanism of electrode processes and the influence of electrode structure on efficiency has not yet been received into the canon of heterogeneous catalysis.
Each author designed his paper to instruct persons not of his discipline concerning some aspect of his subject: some were inevitably more comprehensible and helpful than others. The one theme which ran through many of the papers and much of the discussion was that of the relation between bulk properties and surface reactivity. Professor W. M. H. Sachtler (Leiden) argued on the basis of his own work on the behaviour of Group VIII3 – IB alloys that each atom in the surface acts independently and that therefore the collective electron model is not the right one to use. Dr J. N. Butler (Tyco Laboratories, Waltham, Mass.) produced results which showed some of the limits of the “chemical” approach to alloy properties. He with his associates had studied the hydrogen evolution reaction on dilute amalgams of palladium and platinum, and had found they behaved just as mercury. A platinum amalgam containing 0.03 per cent platinum should have increased the exchange current density by more than 106 fold, and Dr Butler concluded that the absence of surface structure might have been responsible for the lack of effect. Reporting on an extensive study of platinum black as a fuel cell catalyst, Dr Butler said their results indicated particle size to be the most important factor, and that stored energy had no effect on electrocatalytic efficiency.
The symposium served a useful purpose, but more frequent meetings of this kind are essential if the trend towards the compart-mentalisation of science is to be arrested.