Effective　integration　of　CNTs　and　heteroatom-doped　graphene　can　produce　a　new　functional　carbons　that　combines　the　extraordinary　properties　of　heteroatom-doped　graphene　(e.g.,　catalytic　activity,　and　huge　exposed　field)　with　those　of　CNTs　(e.g.,　mechanical　stability,　and　high　electronic　conductivity).　Herein,　we　report　a　straightforward　method　to　manufacture　a　metal-free,　hierarchically　porous　and　N/S　co-doped　CNT-graphene　3D　framework　via　one-step　pyrolysis　of　the　guanine-sulfate　and　OCNTs.　The　usage　of　guanine-sulfate　as　carbon　precursor　can　yield　very　regular　(2D　nanosheet)　and　in　situ　nitrogen-doped　carbons.　By　combining　with　OCNTs,　the　as-obtained　graphene　is　found　to　strongly　couple　with　the　surface　of　CNTs,　achieving　the　uniform　distribution　of　both　components.　Such　3D　hybrid　shows　high　activity　toward　a　set　of　important　electrochemical　reactions　and　high-performance　in　Zn-air　batteries.　Systematic　electrochemical　studies　indicate　the　indispensability　of　both　the　optimal　nitrogen　configuration　and　well-developed　porosity　for　excellent　ORR/OER/HER　performance.　The　amount　of　pyridinic-N　and　graphitic-N,　rather　than　the　total　nitrogen　content,　has　a　more　positive　effect　on　ORR　activity,　particularly　for　the　onset　potential;　while　the　favorable　pore　size　distributions　might　guarantee　a　much　well-developed　diffusion-limited　current　region　and　considerable　diffusion-limited　current　value.　These　results　undoubtedly　could　provide　meaningful　guidance　to　develop　highly　efficient　electrocatalysts.　©　2018　Elsevier　B.V.