The　development　of　high-efficiency　oxygen　evolution　reaction　(OER)　electrocatalysts　is　of　great　importance　for　electrolytic　H2　generation.　In　this　work,　we　report　in-situ　growth　of　MnCo2O4　nanoneedles　and　NiFeRu　layered　double　hydroxide　(LDH)　nanosheets　on　nickel　foam　(NF)　(MnCo2O4@NiFeRu-LDH/NF)　that　can　function　a　highly　efficient　electrode　toward　electrocatalysis　of　OER.　Such　electrode　demands　an　overpotential　of　as　low　as　205　mV　to　reach　10　mA　cm−2　in　alkaline　electrolyte　and　can　run　stably　over　120-hours　continuous　operation.　A　hybrid　flow　acid/alkali　electrolyzer　is　set　up　by　using　the　Pt/C　as　the　acidic　cathode　coupling　with　the　MnCo2O4@NiFeRu-LDH/NF　as　the　alkaline　anode,　which　only　requires　an　applied　voltage　of　0.59　V　and　0.94　V　to　attain　an　electrolytic　current　density　of　10　mA　cm−2　and　100　mA　cm−2,　respectively.　The　present　work　could　push　forward　the　further　development　of　the　electricity-saving　electrolytic　technique　for　H2　generation.　©　2023