Platinum Metals Review - Volume 54, Issue 4, 2010

There are enough platinum group element deposits in the Bushveld Complex in South Africa to supply world demands for many decades or even a century using current mining techniques. Demonstrated reserves and resources published by mining companies make detailed calculations up to a maximum of about twenty years ahead, but there is abundant and adequate geological evidence that these deposits continue far beyond where mining companies have proven according to rigorous international reporting codes. For each 1 km of depth into the Earth in the Bushveld Complex there is in the order of 350 million oz of platinum. For comparison, annual production of platinum from the Bushveld Complex currently is only around 5 million oz. The distinction between ‘reserves’,‘resources’ and ‘deposits’ is also explained in this article.

To investigate the effect of load cycling, platinum (Pt) and platinum-cobalt (PtCo) fuel cell catalysts with different particle sizes were prepared and evaluated for their durability against load cycling. The particle size of the Pt and PtCo catalysts was controlled by changing the catalyst loading and by applying heat treatment. Pt catalysts with particle sizes of 2–3 nm and 4–5 nm and PtCo catalysts with sizes of 3–4 nm, 4–5 nm and 7–8 nm were obtained. A potential sweep from 0.65 V to 1.05 V was applied to the cathode of membrane electrode assemblies (MEAs) prepared with these catalysts,and the degradation of their mass activity and cell voltage were evaluated. As a result of this investigation, it was found that Pt catalysts with particle sizes of 4–5 nm and PtCo catalysts of particle sizes 7–8 nm showed better stability against potential sweep, with the Pt catalysts of sizes 4–5 nm showing the best stability of all the catalysts tested.

The Italian chemist Michele Peyrone (1813–1883) was the first to synthesise cisplatin (cis-diamminedichloro-platinum (II)), the basis of today’s most widely used family of anticancer drugs. This biographical article aims to present, for the first time in the English lan-guage,a summary of his life and the achievements that he made during his scientific career.Originally trained in medicine, Peyrone moved to chemistry and attended some of the most prestigious institutions in Europe in his time. He wrote several publications describing his work on ‘Peyrone’s chloride’ (PtCl2(NH3 )2) and Magnus’ green salt ([Pt(NH3)4][PtCl4]). He later turned his attention to agricultural science where he defended important advances in the understanding of plant growth. Michele Peyrone’s dedication to science is best summarised in the English translation of his first report on the synthesis of cisplatin: “I am determined to pursue this subject with all my energies,with-out having regard for the difficulties to be encountered at every step in so expensive and delicate a research”.