In　this　paper,　CoMo　supported　on　Nb　modified　MgAl　mixed　oxide　by　calcination　of　layered　double　hydroxides　(LDHs)　were　prepared　using　wet　impregnation　method.　The　fresh　calcined　catalysts　were　further　sulfided　by　H2S/H-2　and　tested　for　water-gas　shift　reaction　(WGSR).　The　physicochemical　properties　of　fresh　calcined　catalysts　were　characterized　by　various　adsorption　and　bulk　techniques　like　XRD,　ICP,　N-2-physisorption,　CO2-TPD,　H-2-TPR,　H2S-TPS　and　HRTEM.　It　is　found　that　the　addition　of　Nb　does　not　affect　the　formation　of　LDHs,　but　changes　the　reduction　and　sulfidation　behavior　of　Mo　species　on　oxidic　catalyst　as　well　as　the　dispersion　of　MoS2　phase　on　the　sulfided　catalyst.　The　CoMo/Nb(5%)MgAl　catalyst　shows　the　lowest　apparent　sulfidation　activation　energy,　consumes　the　highest　amount　of　H2S　and　thus　has　the　highest　catalytic　activity　in　WGS　reaction.　(C)　2017　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.