The　2D　graphene　oxide　(GO)　is　promising　for　CO2　2　adsorption,　benefitting　from　its　theoretically　high　specific　surface　area　and　abundant　oxygen-containing　groups.　However,　the　GO　nanosheets　aggregation　renders　the　loss　of　CO2　2　adsorption　site,　reducing　the　CO2　2　adsorption　capability.　To　tackle　this　issue,　we　propose　of　tailoring　physical　and　chemical　structures　of　the　GO　nanosheet　by　etching　and　oxidation,　which　concurrently　enhance　the　specific　surface　area　and　oxygen-containing　functional　groups.　The　etching　step　creates　additional　in-plane　nanopores　in　the　GO　nanosheet　and　uncovers　the　inaccessible　sites　on　the　GO　nanosheet.　The　oxidation　step　produces　more　oxygen-containing　groups,　i.e.,　active　sites,　to　intensify　the　CO2　2　adsorption　of　GO　nanosheets.　Resultantly,　through　enhancing　pore　volume　and　interaction　between　CO2　2　and　oxygenic　functional　group,　the　adsorption　capacity　of　CO2　2　is　promoted.　As　such,　the　CO2　2　adsorption　capability　of　GO　nanosheets　is　significantly　enhanced.　The　optimized　oxidized　porous　GO　nanosheets　are　employed　for　CO2　2　adsorption　after　Ca2+　2　+　cross-　linking,　which　realizes　a　high　CO2　2　adsorption　capability　of　2.5　mmol/g　at　298　K,　1　bar.　Together　with　its　prominent　running　stability,　the　fabricated　porous　GO-based　adsorbents　show　great　potential　for　CO2　2　capture　to　mitigate　the　current　greenhouse　gas　dilemma.