Platinum Metals Review - Volume 20, Issue 2, 1976

The installation of platinum group metal catalysts on 1975 model year U.S. automobiles for control of CO/HC emissions has led to concern over the tendency of such catalysts to oxidise SO2 to sulphuric acid aerosol. Examination of sulphate emissions from Johnson Matthey and Volkswagen test vehicles suggests that although there is some tendency to form sulphate, especially under highly oxidising conditions, the levels of sulphate are in general low. Comparison of measured sulphate conversion with thermodynamic equilibrium values shows that only a small fraction of the available exhaust SO2 is converted to sulphate, and that the catalyst’s ability to convert is shortlived. Future moves toward a three-way catalyst capable of simultaneously converting CO/HC and NOx pollutants should eradicate any tendency towards sulphuric acid formation in automobile exhaust.

The economic use of platinum group metal coatings requires that the most appropriate coating method should be used for any particular application. This article reviews the techniques available for various substrate materials and outlines some of the more important properties obtained with different types of deposit.

An International Conference on hydrogen in metals was held at the University of Birmingham on January 5th and 6th under the auspices of the Faraday Division of the Chemical Society. Over forty papers were presented, many of them dealing with palladium and its alloys. These latter papers are reviewed briefly in this note.

The recent rapid growth of interest in the carboxylato complexes of the platinum group metals has led to many significant advances. This article describes some of the more important chemical, structural and catalytic properties displayed by this class of compound.