The　purification　efficiency　of　auto-exhaust　carbon　particles　in　the　catalytic　aftertreatment　system　of　vehicle　exhaust　is　strongly　dependent　on　the　interface　nanostructure　between　the　noble　metal　component　and　oxide　supports.　Herein,　we　have　elaborately　synthesized　the　catalysts　(Pt/Fe2O3-R)　of　Pt　nanoparticles　decorated　on　the　hexagonal　bipyramid　alpha-Fe2O3　nanocrystals　with　co-exposed　twelve　{113}　and　six　{104}　facets.　The　area　ratios　(R)　of　co-exposed　{113}　to　{104}　facets　in　alpha-Fe2O3　nanocrystals　were　adjusted　by　the　fluoride　ion　concentration　in　the　hydrothermal　method.　The　strong　Pt-Fe2O3{113}　facet　interaction　boosts　the　formation　of　coordination　unsaturated　ferric　sites　for　enhancing　adsorption/activation　of　O-2　and　NO.　Pt/Fe2O3-R　catalysts　exhibited　the　Fe2O3{113}　facet-dependent　performance　during　catalytic　purification　of　soot　particles　in　the　presence　of　H2O.　Among　the　catalysts,　the　Pt/Fe2O3-19　catalyst　exhibits　the　highest　catalytic　activities　(T-50　=　365　degrees　C,　TOF　=　0.13　h(-1)),　the　lowest　apparent　activation　energy　(69　kJ　mol(-1)),　and　excellent　catalytic　stability　during　soot　purification.　Combined　with　the　results　of　characterizations　and　density　functional　theory　calculations,　the　catalytic　mechanism　is　proposed:　the　active　sites　located　at　the　Pt-Fe2O3{113}　interface　can　boost　the　key　step　of　NO　oxidation　to　NO2.　The　crystal　facet　engineering　is　an　effective　strategy　to　obtain　efficient　catalysts　for　soot　purification　in　practical　applications.