Adsorption and reduction of nitrogen monoxide by potassium-doped carbon

Abstract

Neither the adsorption nor the reduction of nitrogen monoxide occurs at 360 °C on pure carbon, but significant reduction of NO, giving N₂ and CO₂, proceeds on potassium-doped carbons. The uptake of NO on carbon is increased markedly by doping potassium salts and the adsorbed NO undergoes decomposition and/or desorption giving N₂O (25–250 °C), NO (250–400 °C) and CO₂(400 °C) in vacuum. Isotope labelling experiments using ¹⁵NO and N₂¹⁸O suggest that the N₂O is produced by the decomposition of (NO)₂(a) and that the NO and CO₂ are caused by the reaction of NO₂(a) with carbon. O(a) and NO₂(a) are the predominant species during the reaction of NO on K-doped carbon, and NO₂(a) suppresses the reaction of NO with carbon.