Single-atom　catalysts　provide　an　effective　approach　to　reduce　the　amount　of　precious　metals　meanwhile　maintain　their　catalytic　activity.　However,　the　sluggish　activity　of　the　catalysts　for　alkaline　water　dissociation　has　hampered　advances　in　highly　efficient　hydrogen　production.　Herein,　we　develop　a　single-atom　platinum　immobilized　NiO/Ni　heterostructure　(Pt-SA-NiO/Ni)　as　an　alkaline　hydrogen　evolution　catalyst.　It　is　found　that　Pt　single　atom　coupled　with　NiO/Ni　heterostructure　enables　the　tunable　binding　abilities　of　hydroxyl　ions　(OH*)　and　hydrogen　(H*),　which　efficiently　tailors　the　water　dissociation　energy　and　promotes　the　H*　conversion　for　accelerating　alkaline　hydrogen　evolution　reaction.　A　further　enhancement　is　achieved　by　constructing　Pt-SA-NiO/Ni　nanosheets　on　Ag　nanowires　to　form　a　hierarchical　three-dimensional　morphology.　Consequently,　the　fabricated　Pt-SA-NiO/Ni　catalyst　displays　high　alkaline　hydrogen　evolution　performances　with　a　quite　high　mass　activity　of　20.6Amg(-1)　for　Pt　at　the　overpotential　of　100mV,　significantly　outperforming　the　reported　catalysts.　While　H-2　evolution　from　water　may　represent　a　renewable　energy　source,　there　is　a　strong　need　to　improve　catalytic　efficiencies　while　maximizing　materials　utilization.　Here,　authors　examine　single-atom　Pt　on　nickel-based　heterostructures　as　highly　active　electrocatalysts　for　alkaline　H-2　evolution.