Metallic-substrate-supported manganese oxide as Joule-heat-ignition catalytic reactor for removal of carbon monoxide and toluene in air

Structured catalysts and reactors have wide applications in environmental remediation and production of important energy-related chemicals. In thermal catalytic processes, external heater are often required to raise the temperature and ignite the reactions, which might lead to huge setups. Herein, we introduce a novel Joule-heat-ignition catalytic reactor. Using Fe-Cr-Al alloy as catalyst substrate, electric currents can pass directly through the substrate, generating Joule heat and bringing the catalysts to the target temperatures. Therefore, the setup can be simplified by omitting the additional heater; the heat produced inside the substrates can be transferred directly to the catalyst coat to achieve rapid ignition; and the reaction temperature can be flexibly controlled by adjusting the input power. In this work, we loaded manganese oxide catalyst onto an alloy wire and used it to build a Joule-heat-ignition reactor for the catalytic oxidation of carbon monoxide and toluene. The anodization pretreatment generated channels on the alloy surface, which effectively enhanced the catalyst loading. The use of alumina as a secondary support also favored catalyst loading and promoted catalyst dispersion. By adding proper amounts of zirconium, the mechanical stability of the catalyst layer increased. The Joule-heat-ignition catalytic system might provide some inspiration in related environmental catalysis.