Selective combustion of hydrogen in the presence of hydrocarbons: Part 2. Metal oxide based catalysts Original Research Article

The selective hydrogen combustion (SHC) properties of some metal-oxide catalysts have been investigated at 500 and 550 °C and atmospheric pressure. This reaction is of importance in the development of new dehydrogenation technology based on partial combustion of hydrogen to provide in situ heat generation to the endothermic dehydrogenation processes. Selective hydrogen combustion in the presence of light hydrocarbons is possible under certain reaction conditions for some catalysts. In2O3/SiO2 and unsupported Bi2O3 are able to selectively combust hydrogen in a gas mixture with propane and oxygen, In2O3/SiO2 being the most active catalyst. Bi2O3/SiO2 and PbOx/SiO2 show moderate properties as selective hydrogen combustion catalysts in the presence of propane. When propene is added to the gas mixture, Bi2O3/SiO2 and PbOx/SiO2 are no longer able to selectively combust hydrogen. In2O3/SiO2, on the other hand, shows a higher activity and combusts hydrogen with 90% selectivity at low oxygen flows, and with 80% selectivity at stoichiometric amounts (to water) of oxygen. The explanation as to why certain oxides are selective is not known, but differences in electronic structure of the oxides can be linked with different SHC properties.