Unique　CO2　methanation　catalysts　comprising　bimetallic　Ni-Rh　nano-alloy/3DOM　LaAlO3　have　been　successfully　prepared　via　a　poly(methyl　methacrylate)　microsphere　colloidal　crystal-templating　route,　followed　by　the　in　situ　growth　of　Ni　nanoparticles　(NPs).　Here,　we　show　that　unlike　traditional　Ni　particles　deposited　on　a　perovskite　support,　the　exsolution　of　Ni　occurs　on　both　the　external　and　internal　surface　of　the　porous　perovskite　substrate,　leading　to　a　strong　metal　support　interaction.　Owing　to　the　exsolution　of　Ni　and　the　formation　of　Ni-Rh　nanoalloys,　a　52%　enhancement　in　the　methanation　turnover　frequency　was　obtained　over　the　Ni-Rh/3DOM　LaAlO3　[13.9　mol/(mol　h)]　compared　to　Rh/3DOM　LaNi0.08Al0.92O3　[9.16　mol/(mol　h)]　before　reduction　treatment.　The　results　show　that　the　low-temperature　reducibility,　rich　surface　adsorbed　oxygen　species,　and　basic　sites　of　the　catalyst　greatly　improve　its　activity　toward　CO2　methanation.　The　hierarchically　porous　structure　of　the　perovskite　support　provides　a　high　dispersion　of　bimetallic　Ni　Rh-NPs.