Co-promoted　MoS2/Al2O3　is　the　industrial-widely　used　catalyst　for　hydrogen　production　by　water-gas　shift　(WGS)　reaction　under　sulfur-containing　condition.　Despite　of　the　intensive　physicochemical　characterizations,　the　intrinsic　activities　of　Co-promoted　and　unprompted　sites　on　this　catalyst　are　still　unreported,　mainly　owning　to　the　lack　of　quantification　method　of　catalytic　sulfide　sites.　With　low　temperature　CO　adsorption　followed　by　IR　spectroscopy,　a　distinguish　technique　developed　by　our　group,　this　short　communication　reports　the　temperature-dependent　TOFs　(turnover　frequencies)　of　these　two　sites,　and　reveals　that　Co-promoted　site　is　intrinsically　much　more　active　than　unprompted　site　at　low　temperatures,　while　these　two　sites　are　catalytically　comparable　at　higher　reaction　temperatures.　The　catalytically　different　performances　are　related　to　the　different　apparent　activation　energies　of　WGS　reaction　on　these　two　sites.　This　work　fills　in　the　long-standing　gaps　in　hydrogen　production　by　WGS　reaction　over　sulfided　CoMo/Al2O3　catalyst.　(C)　2018　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.