Platinum catalysts sensor applications

Metal nano-structures are of considerable interest because of their importance in catalysts, photochemistry, sensors, optical electronic and magnetic devices. Nano-structured platinum is of particular interest for many applications. Platinum nano-structures of... 

Platinum and Platinum Alloys Applications. Platinum and platinum alloys are important constituents of catalysts (chemistry, automotive exhaust gas cleaning, fuel cells), sensor materials (thermocouples, resistance thermometers), strong permanent magnet alloys, magnetic and magnetooptical (memory) devices, high temperature and corrosion resistant stmctural parts, and electrical contacts and connecting elements. Classical applications are jewelry and dentistry alloys. 

As can be seen in Table 11.1, noble metals Pt, Pd, and Rh are the most usable catalysts in calorimetric gas sensors designed. It was established that of all the catalysts known they have the highest activity with respect to oxidation of combustible gases (see Fig. 11.2) and provide acceptable operation temperatures. Morooka and coworkers (Morooka and Ozaki 1966 Morooka et al. 1967) showed that activity for a model reaction, propylene oxidation, correlates with the strength of the metal-oxygen (M-0) bond. Because an LEL sensor must oxidize all ambient hydrocarbon species, the highest activity catalysts hold the most promise for the application. Therefore, the choice of palladium and platinum and sometimes rhodium for application in combustion gas sensors is natural (Miller 2001). This explains why the automobile exhaust system is treated with platinum or palladium compounds and is called a catalytic converter. 

Deng YQ, Neved TG, Ewen RJ, Honeybonme CL, Jones MG (1993) Sulfur poisoning, recovery and related phenomena over supported padadium, rhodiinn and iridium catalysts for methane oxidation. Appl Catal A 101 51-62 Ehrhardt JJ, CoUn L, Jamois D (1997) Poisoning of platinum surfaces by hexamethyldisdoxane (HMDS) application to catalytic methane sensors. Sens Actuators B 40 117-124 Firth JG, Jones A, Jones TA (1973) The principles of the detection of flammable atmospheres by catalytic devices. Combust Flame 21 303-311... 

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