Phase-Transited Lysozyme-Driven Formation of Self-Supported Co3O4@C Nanomeshes for Overall Water Splitting.

The development of highly efficient catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of paramount importance in water splitting. Herein, a phase-transited lysozyme (PTL) is employed as the platform to synthesize nitrogen-doped Co3O4@C nanomesh with rich oxygen vacancies supported on the nickel foam (N-Co3O4@C@NF). This PTL-driven N-Co3O4@C@NF integrates the advantages of porous structure, high exposure of surface atoms, strong synergetic effect between the components and unique 3D electrode configuration, imparting exceptional activity in catalyzing both HER and OER. Remarkably, an alkaline electrolyzer assembled by N-Co3O4@C@NF as both cathode and anode delivers a current density of 10 mA cm-2 at an ultralow cell voltage of 1.40 V, which is not only much lower than that of the commercially noble Pt/C and IrO2/C catalyst couple (≈1.61 V) but also a new record for the overall water splitting. The finding may open new possibilities for the design of bifunctional electrocatalysts for application in practical water electrolysis.