Catalytic and atmospheric effects on microwave pyrolysis of corn stover

► Reaction performance under N2 atmosphere was better than under CO2 atmosphere. ► Metal-oxide catalysts increased the maximum temperature and mass reduction ratio. ► The gas most produced was CO under N2 atmosphere but CO2 under CO2 atmosphere. ► Liquid product should be less toxic due to less PAHs formation. ► More liquid but less gas produced may be due to the Fischer-Tropsch synthesis.