Bifunctional Ni Single Atoms on Graphdiyne‐Porphyrin Analogs Enabling Highly Energy‐Efficient Pulsed Water Splitting

Abstract Transitioning to a sustainable hydrogen‐based economy requires high‐performance, cost‐effective catalysts and energy‐efficient water‐splitting technologies. However, conventional approaches are limited by expensive noble‐metal catalysts, poor metal utilization, and excessive power consumption. This study reports a pulsed water‐splitting strategy using a nickel single‐atom catalyst supported on graphdiyne (GDY) porphyrin analogs (Ni‐SGPA) to address these challenges. By anchoring individual Ni atoms onto a highly conductive π‐conjugated framework with uniform 2.34 nm nanopores, Ni‐SGPA maximizes active site accessibility, reduces metal waste, and lowers material costs. Density‐functional theory (DFT) predicts bifunctionality of Ni‐SGPA with near‐ideal adsorption energies for key *H and *OH intermediates, giving theoretical overpotentials of 0.20 eV for HER and 0.51 eV for OER. Electrochemical tests show low overpotentials of 235 mV (OER) and 295 mV (HER). When Ni‐SGPA is paired with a 3s / 50% duty‐cycle pulsed electrocatalysis protocol, the ON‐period current density rises by 12%, and the process energy demand falls by 42% versus steady‐state operation, with no loss of gas output. Overall, these results highlight Ni‐SGPA's favorable reaction energetics, high bifunctionality, and superior energy efficiency, underscoring its promise as an efficient catalyst for global hydrogen production.