Sir Humphry Davy was born in Penzance on December 17th 1778 and to celebrate the bicentenary of his birth the Royal Institution, where he was Resident Professor from 1802 to 1813 and Honorary Professor for the following ten years, organised a number of lectures and an exhibition illustrating his life and work.

Davy is probably best known to chemists for his isolation of potassium and sodium, and later the alkaline earth elements, by means of the then new methods of electrochemistry, and to the general public for his invention of the miner’s safety lamp—the latter completed in only two weeks of intense investigation. Many other aspects of Davy’s genius, his many decisive experiments, his remarkable series of lectures to crowded audiences at the Royal Institution—to which he gave the character it has ever since retained—and his romantic nature and love of poetry, were all reviewed during the Symposium held during December, but an important but less appreciated phase of his chemical investigations underlies one of the most significant applications of platinum in modern industry.

Davy had excellent opportunities of securing platinum for his experiments. In 1807—the year in which he first electrolysed fused potash in a platinum spoon connected to the positive terminal of a battery—he was elected one of the Joint Secretaries of the Royal Society (he had been elected a Fellow in 1803) his colleague being William Hyde Wollaston. Their association developed into a real friendship, and Davy was able to obtain his requirements from Wollaston, who had only recently succeeded in refining native platinum on a scientific basis and in making malleable platinum available commercially. In addition to their association in the Royal Society Wollaston was among the managers of the Royal Institution, and in the Davy archives preserved there a note gives his appreciation of Wollaston, describing him as

In 1812 Davy published his “Elements of Chemical Philosophy”, the first section comprising a remarkable summary of the history of chemistry. His comments on platinum later in the book are indicative:

One other finding of importance in connection with platinum, made a few years later than the major discovery about to be described, was the change in resistance of a platinum wire with increasing temperature, the basis of course of the modern resistance thermometer. In a paper given to the Royal Society in July 1821 on “Further Researches on the Magnetic Phenomena Produced by Electricity, with some new experiments on the properties of electrified bodies in their relation to conducting powers and temperature” (1), Davy wrote

Among his inspired forecasts were the concepts that

and that the elements might be arranged in the order of their natural resemblances; for example

But the most vital discovery concerning platinum arose during Davy’s classic researches on flame arising from an appeal made to him after a disastrous explosion in a coal mine, followed by a number of other similar explosions in the same area of Northumbria. In a paper read to the Royal Society on January 23, 1817 (2), Davy described “the discovery of a new and curious series of phenomena”.

Thus did Davy discover the phenomenon of heterogeneous catalytic oxidation, and although he obtained the same result with ether, alcohol and other vapours it was left to others to carry further the study of this profoundly important effect. Edmund Davy, his cousin and one-time assistant in the Royal Institution and later Professor of Chemistry at Cork, went on to prepare finely divided platinum catalysts that were active at room temperature (3) while Michael Faraday—sometimes described as Davy’s greatest discovery and his major contribution to science—who was assisting Humphry Davy in the experiments just described, went on much later to the study of catalysis, having been mystified by the peculiar reaction of platinum with the oxygen and hydrogen produced in his experiments on the electrolytic decomposition of water (4).

Davy himself gave little further attention to the phenomenon and made only one passing reference to it in a somewhat obscure place. In 1818 he had published a book “On the Safety Lamp … with Some Researches on Flame”, but in 1825 he was moved to publish a second edition because his experience, as he wrote in the preface

This edition contained several appendices, and in Appendix No. 2 he returned to the subject and to the later work of Dobereiner with finely divided platinum such as Edmund Davy had used (6) and of Dulong and Thenard, who had shown that palladium and iridium could behave catalytically at room temperature while nickel, cobalt, rhodium, silver and gold were active only at higher temperatures (7). Davy continued:

Immediately after the publication of this second edition Davy became ill and exhausted, and after four years of wandering in Europe he died in Geneva at the early age of 50 on May 29, 1829.

A century and a half later some of the questions raised by Davy’s discovery have still not been satisfactorily answered despite intensive research, especially during the past twenty-five years or so. Ignorance of the finer points of reaction mechanism has not, however, proved to be a hindrance to the large-scale usage of catalysed reactions depending upon platinum or its allied metals in modern chemical industry.