Molybdate-intercalated　magnesium–aluminum　hydrotalcite-like　compounds　(HTlc)　were　synthesized　by　anion-exchange　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,　H2-TPR,　and　HAADF-STEM-EDX.　The　characterizations　indicated　that　molybdate　was　well　intercalated　into　the　HTlc　interlayer　as　MoO42–　and　the　Mo　content　was　tunable　by　altering　the　intercalation　degree　of　molybdate.　Upon　calcination,　molybdena　was　dominantly　presented　as　isolated　tetrahedrally　coordinated　MoOx　species.　Upon　nitridation　with　ammonia　at　700　ºC,　highly　dispersed　and　composition-uniform　molybdenum　nitride　(Mo2±xN)　was　formed.　The　Mo0.5Mg3Al　nitride　catalyst　showed　good　activity　for　ammonia　decomposition,　providing　nearly　full　conversion　of　ammonia　at　625　ºC　under　a　space　velocity　of　5,000　mL　gcat–1　h–1.　The　optimal　catalyst　also　exhibited　high　catalytic　stability　during　100　h　operation　at　625　ºC,　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　Mo2±xN　species　was　active　and　stable　for　ammonia　decomposition.　©　2024　Elsevier　B.V.