Cobalt Nitride Supported on Nickel Foam as Bifunctional Catalyst Electrodes for Urea Electrolysis-Assisted Hydrogen Generation.

Replacing the high theoretical potential of anodic water decomposition (oxygen evolution reaction) with the low theoretical potential of urea oxidation reaction (UOR) is an urgent need for hydrogen energy storage and conversion. Cobalt nitride nanoflakes, high-performance bifunctional catalysts supported on nickel foam (Co 5. 4 7 N NF/NF), were synthesized by hydrothermal and calcination method. The morphology and composition of the catalyst were studied by XRD, XPS, SEM, TEM, HRTEM and elemental analysis. In order to conduct electrochemical performance and stability, a two-electrode electrolyzer composed of Co 5. 4 7 N NF/NF as both anode and cathode materials is constructed (Co 5. 4 7 N NF/ NF | | Co 5. 4 7 N NF/NF). Only a voltage of 1.687 V is needed to complete 100 mA ⋅ cm − 2 . It is much lower than the voltage of Pt/ C | | IrO 2 (1.816 V), because of which it is believed that this work provides a valuable route for the design of inexpensive and efficient urea electrolysis-assisted hydrogen generation. A non-noble metal bifunctional catalyst (Co_5.47N NS/NF) was synthesized by simple, low-cost hydrothermal and calcination methods for urea electrolysis-assisted hydrogen production. Co_5.47N NS/NF with unique nanosheets structure was used as both anode and cathode materials, which exhibits better activity and stability than precious metal catalysts. This implies that it is commercially viable. [ABSTRACT FROM AUTHOR]