Ceria　(CeO2)　has　recently　been　found　to　catalyze　the　selective　hydrogenation　of　alkynes,　which　has　stimulated　much　discussion　on　the　catalytic　mechanism　on　various　facets　of　reducible　oxides.　In　this　work,　H-2　dissociation　and　acetylene　hydrogenation　on　bare　and　Ni　doped　CeO2(110)　surfaces　are　investigated　using　density　functional　theory　(DFT).　Similar　to　that　on　the　CeO2(111)　surface,　our　results　suggest　that　catalysis　is　facilitated　by　frustrated　Lewis　pairs　(FLPs)　formed　by　oxygen　vacancies　(O(v)s)　on　the　oxide　surfaces.　On　bare　CeO2(110)　with　a　single　O-v　(CeO2(110)-O-v),　two　surface　Ce　cations　with　one　non-adjacent　O　anion　are　shown　to　form　(Ce3+-Ce4+)/O　quasi-FLPs,　while　for　the　Ni　doped　CeO2(110)　surface　with　one　(Ni-CeO2(110)-O-v)　or　two　(Ni-CeO2(110)-2O(v))　O(v)s,　one　Ce　and　a　non-adjacent　O　counterions　are　found　to　form　a　mono-Ce/O　FLP.　DFT　calculations　indicate　that　Ce/O　FLPs　facilitate　the　H-2　dissociation　via　a　heterolytic　mechanism,　while　the　resulting　surface　O-H　and　Ce-H　species　catalyze　the　subsequent　acetylene　hydrogenation.　With　CeO2(110)-O-v　and　Ni-CeO2(110)-2O(v),　our　DFT　calculations　suggest　that　the　first　hydrogenation　step　is　the　rate-determining　step　with　a　barrier　of　0.43　and　0.40　eV,　respectively.　For　Ni-CeO2(110)-O-v,　the　reaction　is　shown　to　be　controlled　by　the　H-2　dissociation　with　a　barrier　of　0.41　eV.　These　barriers　are　significantly　lower　than　that　(about　0.7　eV)　on　CeO2(111),　explaining　the　experimentally　observed　higher　catalytic　efficiency　of　the　(110)　facet　of　ceria.　The　change　of　the　rate-determining　step　is　attributed　to　the　different　electronic　properties　of　Ce　in　the　Ce/O　FLPs　-　the　Ce　f　states　closer　to　the　Fermi　level　not　only　facilitate　the　heterolytic　dissociation　of　H-2　but　also　lead　to　a　higher　barrier　of　acetylene　hydrogenation.