Hydrogen Cyanide Production During Reduction of Nitric Oxide over Platinum Catalysts: Transient Effects. 
The formation of hydrogen cyanide during the catalytic reduction of nitric oxide (NO) with carbon monoxide and hydrogen was studied with a bench-scale flow reactor.  The previously reported inhibition by sulfur dioxide of the formation of hydrogen cyanide was found to be counteracted by transient admission of oxygen to the catalyst.  These results are discussed in the context of the control of automotive emissions of NO and the prevention of hydrogen cyanide production during such control.