H2S　selective　catalytic　oxidation,　regarded　as　a　green　purification　technology,　has　attracted　much　attention　due　to　its　ability　to　convert　H2S　to　elemental　S　directly　without　thermodynamic　limitation.　Herein,　we　report　for　the　first　time　that　Co　nanoparticles　(NPs)　with　different　Co　content　were　encapsulated　by　N-doped　graphitic　carbon　(3–5　layers)　for　H2S　selective　oxidation.　The　catalytic　performance　of　Co@NC　catalysts　increases　at　first　and　then　decreases　by　increasing　the　content　of　Co.　It　is　found　that　Co@NC-4　with　a　suitable　Co　content　shows　an　optimal　H2S　conversion　ratio　of　nearly　100%　with　the　weight　hourly　space　velocity　of　18000　mL　g−1　h−1　at　190　°C　for　28　h.　This　high　performance　may　be　due　to　optimal　mesopore　size　and　abundant　pyridinic　N.　In　contrast,　NC　sample　without　Co　has　conversed　nearly　95%　of　H2S　at　250　°C.　The　theoretical　calculation　indicates　that　N-doped　graphene　can　regulate　the　electron　density　around　the　Co　NPs,　which　promotes　the　adsorption　of　H2S.　We　believe　that　the　unique　electronic　and　geometrical　configurations　improve　the　activity　and　stability.　Our　finding　provides　a　new　reference　for　the　study　of　H2S　selective　oxidation.　©　2020　Elsevier　B.V.