The　performance-limiting　half　reaction　of　electrochemical　water　splitting　is　the　anodic　oxygen　evolution　reaction　(OER).　The　increased　adsorption,　especially　chemical　adsorption　capacity,　of　the　OER　intermediate　*O　on　anode　materials　is　one　of　the　key　factors　to　improve　the　performance　of　the　anodic　electrocatalysts.　In　this　research,　we　tuned　the　electronegativity　of　anode　materials　to　tailor　their　chemical　adsorption　capacity　in　OER　by　modulating　the　metal　ion　composition　in　the　secondary　building　unit　in　metal-organic　frameworks　(MOFs).　Nanosheet　Fe(III)-MIL-88A　has　been　prepared　as　a　parent　catalyst　in　this　research　due　to　its　high　charger　transfer　capability　and　stability.　Ni2+　ions　with　lower　electronegativity　have　been　introduced　to　exchange　Fe3+　sites　in　Fe(III)-MIL-88A,　which　would　lead　to　decrease　of　the　overall　electronegativity　of　the　MOF　anode,　accompanied　by　the　electron　density　shift　from　Ni2+　to　Fe3+　via　bridge　oxygen.　Porous　MOFs　with　lower　overall　electronegativity　significantly　improved　their　adsorption　capacity　for　*O　intermediate,　thereby　accelerating　the　OER　performance　during　operation.　Our　research　hints　at　the　potential　that　the　electronegativity　of　porous　anodes　could　be　fine-tuned　to　optimize　their　adsorption　capability　for　the　high-efficient　hydrogen　production　during　electrocatalytic　water　splitting.　©　2021　American　Chemical　Society.　All　rights　reserved.