The　research　on　low-cost,　high-performance　non　platinum　group　metal　(PGM)　oxygen　reduction　reaction　(ORR)　catalysts　is　of　great　significance　for　the　rapid　promotion　of　fuel　cells＇　practical　applications.　In　this　work,　Mn-N-C　catalyst　with　outstanding　activity　was　prepared　through　using　hydrogel　formed　by　coordination　of　sodium　alginate　(SA)　and　Mn2+　as　the　precursor.　During　the　preparation　process,　g-C3N4　was　added　to　improve　the　surface　area　enrich　the　pore　structure　of　catalysts,　as　well　as　to　function　as　the　nitrogen　source.　Compare　with　commercial　Pt/C　catalyst,　the　optimum　Mn-N-C　catalyst　possesses　extraordinary　ORR　activity　in　alkaline　electrolytes,　with　a　half-wave　potential　(E　1/2)　of　0.90　V.　In　addition,　the　Mn-N-C　catalyst　also　displays　exceptional　stability　in　alkaline　and　acidic　electrolytes,　much　superior　to　Pt/C　catalyst.　©　2022　IOP　Publishing　Ltd.