Catalytic reduction of oxygen and nitrogen oxides with hydrogen in the offgas of reprocessing plants: laboratory experiments on the properties of the catalyst

The activity and selectivity of 13 commercial noble metal catalysts (Pd, Pt, Ru or their mixtures in finely divided form on Al2O3 support) towards reduction of O2 and NO with H2 were tested. In addition, the behavior of some selected catalysts with respect to overheating and to poisoning by organic phosphate (tributyl phosphate) and iodine was tested. It was found that the Ru catalysts are more suitable than Pt and Pd catalysts for use in cleaning the offgas of reprocessing plants, even though their activity is lower. The main reasons are the higher selectivity of Ru relative to formation of N2 (less formation of NH3) and the lower sensitivity towards poisoning. It can therefore be expected that Ru catalysts will permit longer service lives in such offgas systems