Carbon-based　nonprecious　metallic　electrocatalysts　have　garnered　considerable　attention　due　to　their　tunable　structures,　rapid　electron　transfer,　and　easy　characterization.　There　is　great　anticipation　for　the　development　of　green　and　controllable　methods　for　metal-carbon-based　electrocatalysts.　Molten　salts　synthesis　offers　a　green,　facile　and　effective　approach　for　fabricating　carbon-based　materials,　utilizing　carbon　dioxide　(CO2)　as　the　carbon　source.　In　this　study,　the　co-electroreduction　of　CO2　and　the　binary　metal　oxide　NiCo2O4　is　carried　out　in　a　mixture　of　Li2CO3,　Na2CO3,　and　K2CO3　at　500　degrees　C.　This　process　leads　to　the　formation　of　metal　alloy　nanoparticles　encapsulated　in　a　carbon　matrix　derived　from　CO2,　referred　to　as　NiCo2@C.　The　resulting　NiCo2@C　exhibits　low　overpotential　and　Tafel　slope　(340　mV@10　mA　cm-　2,　67　mV　dec-1)　in　0.1　M　KOH　solution　for　OER,　which　is　superior　to　the　commercial　RuO2　(360　mV@10　mA　cm-　2,　88　mV　dec-1).　Both　experimental　and　theoretical　findings　indicate　the　synergistic　effects　of　Ni/Co　bimetallic　sites.　Spontaneous　adsorption　of　hydroxide　ion　on　the　bridging　sites　of　heterologous　diatoms　facilitates　the　adsorption　and　desorption　of　intermediates　during　the　OER　process.