Molybdate-intercalated　magnesium-aluminum　hydrotalcite-like　compounds　(HTlc)　were　synthesized　by　anionexchange　and　used　as　precursor　to　prepare　supported　molybdenum　nitride　catalyst　for　ammonia　decomposition.　The　as-synthesized　precursors　and　the　derived　mixed　metal　oxides　and　nitride　catalysts　were　characterized　by　ICP,　XRD,　Raman　spectroscopy,　XPS,　H　2　-TPR,　and　HAADF-STEM-EDX.　The　characterizations　indicated　that　molybdate　was　well　intercalated　into　the　HTlc　interlayer　as　MoO　4　2-　and　the　Mo　content　was　tunable　by　altering　the　intercalation　degree　of　molybdate.　Upon　calcination,　molybdena　was　dominantly　presented　as　isolated　tetrahedrally　coordinated　MoO　x　species.　Upon　nitridation　with　ammonia　at　700　degrees　C,　highly　dispersed　and　composition-uniform　molybdenum　nitride　(Mo　2　+/-　x　N)　was　formed.　The　Mo　0.5　Mg　3　Al　nitride　catalyst　showed　good　activity　for　ammonia　decomposition,　providing　nearly　full　conversion　of　ammonia　at　625　degrees　C　under　a　space　velocity　of　5,000　mL　g　cat-1　h　-1　.　The　optimal　catalyst　also　exhibited　high　catalytic　stability　during　100　h　operation　at　625　degrees　C,　and　no　obvious　aggregation　took　place,　attributable　to　the　strong　metal-support　interaction　between　molybdenum　nitride　and　Mg-Al　mixed　oxide.　It　is　suggested　that　the　hydrotalcite-derived　Mg-Al　mixed　oxide　supported　highly　dispersed　Mo　2　+/-　x　N　species　was　active　and　stable　for　ammonia　decomposition.