Nanometer　perovskite-type　oxides　La1-xSrxMO3-delta　(M　=　CO,　Mn;　x　=　0,　0.4)　have　been　prepared　using　the　citric　acid　complexing-hydrothermal-coupled　method　and　characterized　by　means　of　techniques,　such　as　X-ray　diffraction　(XRD),　BET,　high-resolution　scanning　electron　microscopy　(HRSEM),　X-ray　photoelectron　spectroscopy　(XPS),　temperature-programmed　desorption　(TPD),　and　temperature-programmed　reduction　(TPR).　The　catalytic　performance　of　these　nanoperovskites　in　the　combustion　of　ethylacetate　(EA)　has　also　been　evaluated.　The　XRD　results　indicate　that　all　the　samples　possessed　single-phase　rhombohedral　crystal　structures.　The　surface　areas　of　these　nanomaterials　ranged　from　20　to　33　m(2)　g(-1),　the　achievement　of　such　high　surface　areas　are　due　to　the　uniform　morphology　with　the　typical　particle　size　of　40-80　nm　(as　can　be　clearly　seen　in　their　HRSEM　images)　that　were　derived　with　the　citric　acid　complexing-hydrothermally　coupled　strategy.　The　XPS　results　demonstrate　the　presence　of　Mn4+　and　Mn3+　in　La1-xSrxMO3-delta　and　Co3+　and　Co2+　in　La1-xSrxMO3-delta,　Sr　substitution　induced　the　rises　in　Mn4+　and　Co3+　concentrations;　adsorbed　oxygen　species　(O-,　O-2(-),　or　O-2(2-))　were　detected　on　the　catalyst　surfaces.　The　02-TPD　profiles　indicate　that　Sr　doping　increased　desorption　of　the　adsorbed　oxygen　and　lattice　oxygen　species　at　low　temperatures.　The　H-2-TPR　results　reveal　that　the　nanoperovskite　catalysts　could　be　reduced　at　much　lower　temperatures　(＜240　degrees　C)　after　Sr　doping.　It　is　observed　that　under　the　conditions　of　EA　concentration　=　1000　ppm,　EA/oxygen　molar　ratio　=　1/400,　and　space　velocity　=　20,000　h(-1),　the　catalytic　activity　(as　reflected　by　the　temperature　(T-100%)　for　EA　complete　conversion)　increased　in　the　order　of　LaCoO2.91　(T-100%　=　230　degrees　C)　approximate　to　LaMnO3.12　(T-100%　=　235　degrees　C　＜　La0.6Sr0.4MnO3.02　(T-100%　=　190　degrees　C　＜　La0.6Sr0.4CoO2.78　(T-100%　=　175　degrees　C);　furthermore,　there　were　no　formation　of　partially　oxidized　by-products　over　these　catalysts.　Based　on　the　above　results,　we　conclude　that　the　excellent　catalytic　performance　is　associated　with　the　high　surface　areas,　good　redox　properties　(derived　from　higher　Mn4+/Mn3+　and　CO3+/　CO2+　ratios),　and　rich　lattice　defects　of　the　nanostructured　La1-xSrxMO3-delta　materials.　(C)　2007　Elsevier　B.V.　All　rights　reserved.