Cobalt　oxide　is　a　typical　transition　metal　oxide　that　exhibits　high　catalytic　activity　for　the　total　oxidation　of　volatile　organic　compounds.　In　this　study,　a　reduction　process　in　a　glycerol　solution　was　adopted　to　generate　mesoporous　CoO　(meso-CoO)　or　CoOx　(meso-CoOx)　from　mesoporous　Co3O4　(meso-Co3O4).　The　obtained　samples　were　rich　in　Co2+　species　and　exhibited　high　catalytic　activity　for　o-xylene　oxidation.　The　meso-CoOx　sample　with　the　largest　surface　Co2+　amount　performed　the　best:　The　o-xylene　conversion　at　240　degrees　C　was　83%,　and　the　reaction　rate　over　meso-CoOx　was　nine　times　higher　than　that　over　meso-Co3O4.　It　is　found　that　the　samples　with　more　surface　Co2+　species　possessed　better　oxygen　activation　ability,　and　the　Co2+　species　were　the　active　sites　that　favored　the　formation　of　highly　active　O-2(-)　and　O-2(2-)　(especially　O-2(-))　species.　(C)　2017　Elsevier　Inc.　All　rights　reserved.