Direct formation of formaldehyde from methane and carbon dioxide over vanadium oxide catalysts

✍ Scribed by Takahiro Shimamura; Kimito Okumura; Kiyoharu Nakagawa; Toshihiro Ando; Na-oki Ikenga; Toshimitsu Suzuki

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 132 KB
• Volume: 211
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2003.09.026

✦ Synopsis

The possibility of CO 2 as an alternative oxidant for the direct conversion of CH 4 to formaldehyde was investigated. The activity of the catalyst was measured at an atmospheric pressure and temperatures at which the homogeneous gas-phase reactions were negligible. Among various metal oxides loaded on SiO 2 catalysts, only vanadium oxide produced the desired product. V 2 O 5 /SiO 2 and V 2 O 5 /oxidized diamond catalysts, the most effective catalysts for formaldehyde synthesis, afforded about 500 mol h -1 g-cat -1 and 300 mol h -1 g-cat -1 of formaldehyde at 973 K, respectively. When the reaction of CH 4 was carried out in Ar atmosphere, both of the V 2 O 5 /SiO 2 and V 2 O 5 /oxidized diamond catalysts lost the catalytic activity as soon as the lattice oxygen of vanadium oxide was consumed. However, the activity recovered by switching the atmosphere from Ar to CO 2 . These results strongly suggest that CO 2 acts as an oxidant for selective oxidation of CH 4 to formaldehyde via the lattice oxygen of vanadium oxide.