Abstract: Particles of alloys of a noble metal chosen from among iridium, osmium, palladium, platinum, rhodium and ruthenium, hereafter represented by M, with at least one non-noble metal chosen among silver, bismuth, cadmium, cobalt, copper, tin, germanium, indium, manganese, mercury, molybdenum, nickel, gold, lead, rhenium, thallium, tellurium, technetium, tungsten, vanadium and zinc, hereafter referred to as Me', and Me', representing at least one non-noble metal, characterized in that they correspond to the general formulaM.sub.n Me'.sub.mwhere n represents an integer equal to 1, 2 or 3 and where m represents an integer equal to 1, 2 or 3, and in that their specific surface area is between 0.5 and 800 m.sup.2 /g of alloy and in that the mean diameter of the alloy particles is between 10 and 10,000 A.The particles are prepared by reducing the mixed oxides of the corresponding formulaM.sub.n Me'.sub.m O.sub.xThey are used as catalyst for dehydrogenation or hydrogenation.

Abstract: Disclosed is a method of purifying exhaust gases from an internal combustion engine operated with a substantially stoichiometric fuel-to-air mixture, the gases having an L-value of from about 0.8 to 1.2, wherein the exhaust gases are brought into contact with a catalyst comprising molybdenum, rhodium and, optionally, platinum supported on a carrier.

Abstract: A coating composition for application to an electrically conductive and relatively inert support at least the surface layer of which is titanium or a titanium alloy, to form a coated electrode for electrochemical processes, the composition essentially containing thermally decomposable compounds of iridium and of at least one non noble element selected from the group consisting of lithium, boron, beryllium, magnesium, gallium and germanium, in a liquid vehicle, the atomic ratio of iridium/non noble element being between 1/4 and 8/1. An electrode provided with a coating of this composition exhibits, inter alia, increased service life.