Perovskite-type　oxide　La0.5Sr0.5MnO3-delta　catalysts　were　fabricated　hydrothermally　at　220,　240,　250　or　270　degrees　C　for　50　h　(denoted　as　LSMO-220,　LSMO-240,　LSMO-250,　and　LSMO-270,　respectively).　We　characterized　the　materials　by　a　number　of　analytical　techniques.　It　was　found　that　the　La0.5Sr0.5MnO3-delta　samples　are　single-crystalline　cubic　perovskite-type　oxides　in　the　form　of　microcubes.　The　as-fabricated　samples　displayed　various　surface　and　bulk　compositions　that　can　be　related　to　the　discrepancy　in　treatment　temperature.　The　surface　Mn/(La　+　Sr　+　Mn)　ratio　and　the　initial　H-2　consumption　rate　at　low-temperatures　increase　according　to　the　sequence　of　LSMO-240　＜　LSMO-270　＜　LSMO-220　＜　LSMO-250.　We　observed　that　the　surface　Mn4+/Mn3+　ratio　and　catalytic　performance　of　the　materials　follow　a　similar　order.　The　temperature　for　100%　toluene　conversion　over　LSMO-250　was　280　degrees　C.　The　excellent　performance　of　the　materials　can　be　related　to　(i)　Mn　surface　enrichment,　(ii)　high　Mn4+/Mn3+　ratio,　(iii)　oxygen　nonstoichiometry,　and　(iv)　single-crystalline　structure　of　the　catalysts.　(C)　2008　Elsevier　B.V.　All　rights　reserved.