Exploring　advanced　electrolysis　techniques　for　attaining　scene-adaptive　and　on-site　green　H2　production　is　an　imperative　matter　of　utmost　practical　significance　but　grand　challenge　remains.　Herein,　drawn　inspiration　from　a　spontaneous　hydrazine‒H2O　galvanic　cell　configured　on　a　low-valence　Ru　single　atoms-loaded　Mo2C　electrode　(RuSA/v-Mo2C),　an　alternative　H2　energy　solution　utilizing　self-powered　electrochemical　hydrazine　splitting　(N2H4　→　2H2　+　N2)　instead　of　the　stereotyped　electricity-consumed　water　splitting　for　green　H2　production　is　proposed.　This　solution　highlights　a　pH-decoupled　hydrazine‒H2O　primary　battery　with　notable　open-circuit　voltage　of　1.37　V　and　energy　density　up　to　358　Wh　gN2H4−1,　which　powerfully　propels　an　alkaline　hydrazine　splitting　cell,　leading　to　bilateral　H2　harvest　with　a　remarkable　rate　of　18　mol　h−1　m−2,　i.e.,　403.2　L　h−1　m−2,　setting　a　new　record　for　the　self-sustaining　electricity-powered　H2　production　systems.　The　success　of　RuSA/v-Mo2C　for　this　solution　is　further　decoded　by　tandem　theoretical　and　in　situ　spectroscopic　studies,　cross-verifying　a　Ru‒Mo　dual-site　synergy　in　streamlining　the　overall　energy　barriers,　thereby　enhancing　the　kinetics　of　electrode　reactions.　This　pioneering　work,　showcasing　electrochemical　H2　production　free　from　both　external　energy　and　feedstock　inputs,　opens　up　a　new　horizon　on　way　of　the　ultimate　H2　energy　solution.　©　2025　Wiley-VCH　GmbH.