Multiscale design of 3D metal–organic frameworks (M−BTC, M: Cu, Co, Ni) via PLAL enabling bifunctional electrocatalysts for robust overall water splitting

•Multiscale design of 3D MOF (M−BTC, M: Cu, Co, Ni) was demonstrated via PLAL.•Studied intrinsic properties on electrocatalytic active-states for overall water splitting.•Co-BTC achieve low η10 of 437 and 370 mV for HER and OER, respectively.•Require only 2.03 V @ 10 mA/cm2 for Co–BTC ∥ Co–BTC full electrolysis system.•Electronic effect implying on structural stability and long-term durability.