Despite　the　known　efficacy　of　CeO2　as　a　promoter　in　alkaline　hydrogen　evolution　reaction　(HER),　the　underlying　mechanism　of　this　effect　remains　unclear.　CoS2,　a　pyrite-type　alkaline　HER　electrocatalyst,　suffers　from　sluggish　HER　kinetics　and　severe　catalyst　leaching　due　to　its　weak　water　dissociation　kinetics　and　oxygen-related　corrosion.　Herein,　it　is　demonstrated　that　the　interfacial　Lewis　acid-base　Ce　center　dot　center　dot　center　dot　S　pairs　in　CeO2-loaded　CoS2　effectively　improve　the　catalytic　activity　and　durability.　In　CeO2-loaded　CoS2　nanowire　array　electrodes,　these　interfacial　Lewis　acid-base　Ce　center　dot　center　dot　center　dot　S　pairs　with　unique　electronic　and　structural　configurations　efficiently　activate　water　adsorptive　dissociation　and　kinetically　accelerate　hydrogen　evolution,　delivering　a　low　overpotential　of　36　mV　at　10　mA　cm(-2)　in　alkaline　media.　Such　Ce　center　dot　center　dot　center　dot　S　pairs　also　weaken　O-2　adsorption　on　CoS2,　leading　to　undecayed　activity　over　1000　h.　These　findings　are　expected　to　provide　guidance　for　the　design　of　CeO2-based　electrocatalysts　as　well　as　other　hybrid　electrocatalysts　for　water　splitting.