Platinum catalyst poison with below

The above tabulation refers especially to toxicity in catalytic hydrogenation towards a catalyst such as platinum, palladium, or nickel, and the greater part of the experimental work has been done with platinum catalysts at temperatures below 100°C. but the principle also applies to other catalytic reactions provided that the molecular form of the poison is stable under the conditions employed. 

Catalyst layers based on pure platinum require comparatively clean reactants pure platinum works with CO contaminations below 1 ppm and CO2 less than 10%. Appropriate fuels are therefore either pure hydrogen or purified reformate. Higher concentrations of CO or CO2 lead to a steady decrease of the performance due to catalyst poisoning. For reformate use without a purification step, platinum-ruthenium alloys are used leading to a typical loading of 0.3 gp,Ru/kWg, at the anode and 0.3 gpj/kW, at the cathode. 

The development of these catalysts occurred in an atmosphere of tight secrecy, and little has been published on those efforts. All three were of the particulate type one contained noble metal(s) while the other two were noble-metal promoted base-metal catalysts (16). The UOP noble metal catalyst was provided several years later to GM and to Ford for evaluation with unleaded fuel and for other studies, and it can be deduced that it was supported on low-density (about 0.32 g/mL apparent bulk density) 1/8 inch spheres (17) and may have contained about 0.47 troy ounces of platinum per cubic foot (ca. 0.16 weight percent), with the platinum concentrated in a subsurface shell some distance below the exterior surfaces of the spheres for improved poison resistance (18) The Cyanamid catalyst was later studied by Ford (16, 19) it apparently was an extrudate (1/8" diameter x 1/8" long) of about 0.67 g/mL ABD, with about 125 ppm (weight) of palladium and 5 weight % each of CuO and 2 5 Si02 95% AI2O3 support of about... 

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