The Use of Platinum Powder
Platinum (Pt) is a fine powder of platinum with good catalytic properties, and the CAS NO. is 7440-06-4. The name of platinum black is due to its black color.
Platinum powder is widely used as a thin film covering solid platinum metal, forming platinum electrodes for applications in electrochemistry. The process of covering platinum electrodes with such a layer of platinum black is called "platinization of platinum". The platinized platinum has a true surface area higher than the geometrical surface area of the electrode and, so, exhibits catalytic action superior to that of shiny platinum.
Platinum powder is used as a catalyst in proton exchange membrane fuel cells. In common practice, the platinum powder is either sprayed or hot pressed onto the membrane or gas diffusion layer. A suspension of platinum black and carbon powder in ethanol-water solutions serves to optimize the uniformity of the coating, electrical conductivity, and in the case of application to the membrane, to prevent dehydration of the membrane during the application.