Characteristics of Formaldehyde Formation from Catalytic Reaction of Methane in the Presence of NO.

Experiments have been carried out to investigate the inhibitory effect on catalytic reaction of methane and the formation of formaldehyde in the presence of nitric oxide(NO). Catalysts used in the experiment were Pd, Pt, Rh, Pd/Pt/Rh loaded on γ-Al2O3 monolith. With all these catalysts, the presence of NO and NO2 showed inhibitory effects on methane oxidation reaction and caused the formation of formaldehyde. In the absence of oxygen, however, formaldehyde was not produced in the catalytic reaction of methane and NO. Maximum formation of formaldehyde was about 0.6% in the presence of NO with the Pt, Pd/Pt/Rh or Rh catalysts. It was also found that N2O was formed simultaneously with formaldehyde in the catalytic reaction of methane in the presence of NO.