Photocatalytic　conversion　of　diluted　CO2　into　solar　fuel　is　highly　appealing　yet　still　in　its　infancy.　Herein,　we　demonstrate　the　metal-node-dependent　performance　for　photoreduction　of　diluted　CO2　by　constructing　Ni　metal–organic　framework　(MOF)　monolayers　(Ni　MOLs).　In　diluted　CO2　(10　%),　Ni　MOLs　exhibit　a　highest　apparent　quantum　yield　of　1.96　%　with　a　CO　selectivity　of　96.8　%,　which　not　only　exceeds　reported　systems　in　diluted　CO2　but　also　is　superior　to　most　catalysts　in　pure　CO2.　Whereas　isostructural　Co　MOLs　is　almost　inactive　in　diluted　CO2,　indicating　the　performance　is　dependent　on　the　metal　nodes.　Experimental　and　theoretical　investigations　show　that　strong　CO2　binding　affinity　of　Ni　MOLs　is　the　crucial　factor,　which　stabilizes　the　Ni-CO2　adducts　and　facilitates　CO2-to-CO　conversion.　©　2018　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim