Although　single-atom　catalysts　significantly　improve　the　atom　utilization　efficiency,　the　multistep　preparation　procedures　are　complicated　and　difficult　to　control.　Herein,　we　demonstrate　that　one-step　in　situ　synthesis　of　the　single-atom　Pt　anchored　in　single-crystal　MoC　(Pt-1/MoC)　by　using　facile　and　controllable　arc-discharge　strategy　under　extreme　conditions.　The　high　temperature　(up　to　4000　degrees　C)　provides　the　sufficient　energy　for　atom　dispersion　and　overall　stability　by　forming　thermodynamically　favourable　metal-support　interactions.　The　high-temperature-stabilized　Pt-1/MoC　exhibits　outstanding　performance　and　excellent　thermal　stability　as　durable　catalyst　for　selective　quinoline　hydrogenation.　The　initial　turnover　frequency　of　3710h(-1)　is　greater　than　those　of　previously　reported　samples　by　an　order　of　magnitude　under　2MPa　H-2　at　100　degrees　C.　The　catalyst　also　shows　broad　scope　activity　toward　hydrogenation　containing　unsaturated　groups　of　C=C,　C=N,　and　C=O.　The　facile,　one-step,　and　fast　arc-discharge　method　provides　an　effective　avenue　for　single-atom　catalyst　fabrication　that　is　conventionally　challenging.