The　three-dimensional　mesoporous　calcium　oxide　(meso-CaO)　supported　chromium-vanadium　binary　oxide　catalysts　yCrO(x)/10　wt.%　VO(x)/meso-CaO　(i.e.,　yCr/10V/meso-CaO,　y=0-4　wt.%;　the　VO(x)　and　CrO(x)　weight　percentages　referred　to　the　mass　contents　of　V(2)O(5)　and　Cr(2)O(3)　in　the　catalysts,　respectively)　were　prepared　via　an　incipient　wetness　impregnation　route　and　characterized　by　means　of　XRD,　BET,　SEM,　TEM/SAED　(selected-area　electron　diffraction),　Raman,　and　H(2)-TPR　(temperature-programmed　reduction)　techniques.　The　catalytic　performance　of　the　materials　was　evaluated　for　the　oxidative　dehydrogenation　(ODH)　of　isobutane.　It　is　found　that　the　meso-CaO　and　yCr/10V/meso-CaO　displayed　wormhole-like　mesoporous　structures,　VO(x)　and/or　CrO(x)　were　highly　dispersed　in　the　form　of　mono-　and　polyvanadate　or　polychromate　on　the　surface　of　the　meso-CaO　support.　The　H(2)-TPR　results　indicate　that　2Cr/10V/meso-CaO　exhibited　the　best　low-temperature　reducibility　among　the　as-prepared　catalysts.　Under　the　conditions　of　isobutane/oxygen　molar　ratio　=　1/2,　space　velocity　=　30,000　mL/(g　h),　and　temperature　=　540　degrees　C,　a　maximal　C(4)-olefins　yield　of　15%　with　the　corresponding　C(4)-olefins　selectivity　of　79%　was　achieved　over　the　2Cr/10V/meso-CaO　catalyst.　It　is　concluded　that　the　good　dispersion　of　CrO(x)　and　VO(x)　domains　and　low-temperature　reducibility　of　the　catalyst　as　well　as　the　strong　basicity　and　three-dimensional　wormhole-like　mesoporosity　of　the　CaO　support　were　responsible　for　the　excellent　catalytic　performance　of　2Cr/10V/meso-CaO　for　the　ODH　of　isobutane.　(C)　2010　Elsevier　B.　V.　All　rights　reserved.