The activity of knitted silica-fibre supported Pd, Pt, Pt-Ni, Pd-Ni and Pd-Pt-Ni catalysts as well as Pd based H-ZSM-5 and H-ZSM-35 catalysts was studied in the conversion of gas mixtures containing 200 ppm CH4, 2500 ppm CO, 500 ppm pyridine (or 500 ppm NO), 10 Vol.% O-2 (or 0.155 vol.% O-2), 12 vol.% CO2 12 vol.% H2O, balanced with He at GHSV of 60000 h(-1). Pyridine was found to inhibit both CO and CH4 oxidation. IR studies indicated that NO adsorbed on Pd2+ is the principal adsorbed species on the Pd/HZSM-5 catalyst.