Platinum Metals Review - Volume 21, Issue 3, 1977

The use of platinum group metal catalysts supported on ceramic monoliths for control of gaseous emissions from automobiles and chemical plant is now well established. Research in the Johnson Matthey Laboratories and at AERE Harwell, aimed at meeting the demand for more effective catalysts, has resulted in a new generation of platinum catalysts in which the ceramic substrate is replaced by a metal monolith. These metal substrate platinum catalysts are found to be more compact and more efficient than conventional ceramic structures. At the same time they overcome the structural limitations of ceramics with greater resistance to thermal shock and mechanical failure. The development of the metal substrate catalyst, and its use in hostile high temperature environments such as automobile emission control and catalytic combustion is described.

Many of the platinum group intermetallic compounds possess unique properties which may occur in most interesting combinations. This paper draws attention to a number of these and briefly describes some applications for them. It suggests that further study is required before a full appreciation can be made of their perhaps considerable potential for use in hostile environments.

Many industrial processes produce hydrocarbon vapours which, if released to the atmosphere, contribute to the general pollution of the environment. The discharge of such vapours is now, not unnaturally, being subject to legislative control in many places as the extent of the damage resulting from such pollution is more fully realised. Platinum catalyst control systems are being increasingly employed to prevent air pollution as the cost benefits of employing such systems, are becoming more generally known. This paper describes the system one enterprising organisation has successfully employed to comply with the strict pollution control regulations in Los Angeles, a region where topography and climatic conditions result in particularly difficult pollution problems, while at the same time making substantial savings in fuel.

Heterogeneous versions of homogeneous catalysts can often be produced and may have certain advantages in use particularly on a commercial scale. The catalytic chemistry of supported rhodium compounds for the carbonylation of methanol is described and the behaviour of heterogeneous and homogeneous operation compared in order to illustrate the relations between the two catalyst types. Particular attention is given to the factors which influence the activity and the selectivity of the heterogenised forms.