This study presents the synthesis of phosphide/ layered double hydroxide (LDH) heterostructures consisting of Ni-Co-P and Ni-Co-Mn-LDH. Morphological manipulation and the construction of heterostructures were employed to significantly enhance catalytic performance for hydrogen production through electrochemical urea-assisted water splitting. The dynamic hydrogen bubble template (DHBT) method effectively deposited the phosphide layer, resulting in a three-dimensional highly porous structure conducive to catalytic reactions. The electrochemical evaluation of the hydrogen evolution reaction (HER) demonstrated that the Ni-Co-Mn-LDH/Ni-Co-P/NF electrode achieves an overpotential of 56 mV (vs. RHE) at a current density of 10 mA.cm⁻², a significant improvement compared to the Ni-Co-P/NF electrode overpotential of 103 mV at the same current density. Moreover, replacing the oxygen evolution reaction (OER) with the urea oxidation reaction (UOR) in the water-splitting process enables the cell potential to achieve 1.45 V at a current density of 10 mA.cm⁻², which is 160 mV reduced compared to that of the HER-OER combination. Electrochemical tests also demonstrated a remarkable improvement in the activity of the phosphide layer upon the incorporation of the LDHs, with a twofold increase in the electrochemically active surface area (ECSA) and a threefold reduction in charge transfer resistance (Rct) following the deposition of Ni-Co-Mn-LDH on Ni-Co-P. Results demonstrated enhanced hydrophilicity of the catalysts, along with improved bubble detachment dynamics. Stability tests and comprehensive evaluations of urea-assisted water splitting, indicated that the LDH/phosphide catalysts function effectively as dual-functional catalysts. These findings highlight the potential of tailored heterostructures in optimizing electrocatalytic processes for hydrogen production.

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