Highly Synergistic Co3+ and Pyridinic‐N‐Rich Bifunctional Electrocatalyst for Ultra‐Low Energy‐Driven Effective Hydrogen Production and Urea Oxidation

Abstract Metal–organic framework (MOF)‐derived electrocatalysts exhibit enhanced electrochemical water splitting with significant durability. However, they cannot drive the required current density at a lower overpotential (η) compared to other benchmark catalysts. To overcome the lack of efficient catalytic activity, Co 3 O 4 ‐embedded nitrogen‐doped carbon (NC) is fabricated on NiO nanosheets derived from an in situ synthesized Co MOF with an electrodeposited (Ni(OH) 2 ) layer. The electrocatalyst developed herein comprises many Co 3+ , Ni 3+ , and pyridinic‐N‐exposed active centers and exhibits an excellent synergistic effect between the metal oxide–NC–metal oxide, facilitating a highly efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Owing to the highly intimate contact between the electrocatalyst layers, rapid electron transfer occurs and a current density of 10 mA cm ‐2 is produced in the HER and OER at η of 73 and 110 mV, respectively, with excellent mass activity and high turnover frequency. However, urea‐assisted water electrolysis achieves current densities of 10 and 100 mA cm ‐2 at cell voltages of just 1.31 and 1.49 V, respectively, for the two‐electrode‐based system, with an extremely stable durability of 212 h (1.49 V). Co 3 O 4 @NC/NiO ∥ Co 3 O 4 @NC/NiO has a considerably better urea electrolysis performance than other benchmark electrocatalysts.