Monolithic Ni-Al2O3/Ni-foam catalyst is developed by modified wet chemical etching of Ni-foam, being highly active/selective and stable in strongly exothermic CO2 methanation process. The as-prepared catalysts are characterized by x-ray diffraction scanning electron microscopy, inductively coupled plasma atomic emission spectrometry, and H-2-temperature programmed reduction-mass spectrometry. The results indicate that modified wet chemical etching method is working efficiently for one-step creating and firmly embedding NiO-Al2O3 composite catalyst layer (approximate to 2 m) into the Ni-foam struts. High CO2 conversion of 90% and high CH4 selectivity of >99.9% can be obtained and maintained for a feed of H-2/CO2 (molar ratio of 4/1) at 320 degrees C and 0.1 MPa with a gas hourly space velocity of 5000 h(-1), throughout entire 1200 h test over 10.2 mL such monolithic catalysts. Computational fluid dynamics calculation and experimental measurement consistently confirm a dramatic reduction of hotspot temperature due to enhanced heat transfer. (c) 2015 American Institute of Chemical Engineers