Chemical　hydrogen　storage　is　an　important　area　for　hydrogen　fuel　cell　applications　while　catalyst　is　the　key　to　develop　effective　hydrogen　production　process　for　fuel　cell　applications.　Platinum　is　a　superior　catalyst　for　decalin　dehydrogenation,　and　support　modification　can　improve　the　catalysis.　Effects　of　different　supports,　preparation　methods　and　Mg/Al　molar　ratio　on　the　material　properties　and　the　catalytic　performance　of　the　Pt　catalysts　were　thus　systematically　investigated.　The　results　showed　that　the　MgAl2O4　support　was　more　suitable　for　improving　Pt　dispersion　and　forming　smaller　Pt　nanoparticles　than　the　others.　The　Pt/MgAl2O4　with　Mg/Al　molar　ratio　of　0.5　prepared　by　alcohol-heating　method　demonstrated　superior　performance,　which　is　closely　related　to　the　Pt　nanoparticle　size　and　reaction　state.　Initial　ratio　of　decalin　to　catalyst　also　played　an　important　role　in　the　activity　and　was　achieved　the　optimal　ratio　in　the　liquid-film　state.　Graphical　Abstract:　[Figure　not　available:　see　fulltext.]　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.