Complete oxidation of lean methane over metal oxide supported Pd catalysts: Current advancement and future perspectives

Due to the increasing greenhouse effect caused by the escape of methane in the oxidation process, the complete oxidation technology of methane has attracted much attention. This review summarizes the recent researches on the design of metal oxide supported Pd catalysts for the complete oxidation of methane, including the catalytic mechanism of the catalysts, the properties of Pd species, and the development of various metal oxide supports. In the catalytic oxidation of methane, the Mars-van Krevelen mechanism is widely accepted. The active phase in the catalyst mainly consists of PdO(101)-Pd0, and PdO2 could also be the active phase when the Pd-MOx solid solution is formed. Among various supports, metal oxides with multiple oxidation states are more suitable as support materials for Pd because they normally have abundant oxygen vacancies and higher active oxygen transfer capacity. Finally, some reasonable suggestions for the future direction of work are put forward. This work will provide a new inspiration in the development of highly efficient Pd catalysts for the complete oxidation of methane.