Bifunctional electrocatalytic performance of MgAlCe-LDH/β-Ni(OH)₂/Ni foam in total natural seawater splitting.

Abstract

Electrocatalytic seawater splitting is a potential solution to environmental problems, as seawater is a plentiful supply of hydrogen sources in nature. Hence, the development of bifunctional electrodes exhibiting outstanding performance in both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is essential for the efficacy of total seawater splitting. Herein, we employed a straightforward method for in situ creation of β-Ni(OH)₂ on Ni foam, followed by a hydrothermal approach to manufacture MgAlCe-LDH on β-Ni(OH)₂/Ni foam. The linear sweep voltammetry (LSV) experiments demonstrate that the MgAlCe-LDH/β-Ni(OH)₂/Ni foam exhibits superior performance for both the OER and the HER in a natural seawater electrolyte compared to the MgAlCe-LDH/Ni foam, β-Ni(OH)₂/Ni foam, and Ni foam. Consequently, the MgAlCe-LDH/β-Ni(OH)₂/Ni foam requires an 80 mV overpotential for OER and 337 mV for HER to attain a current density of 10 mA cm^-2. The enhanced electrocatalytic activity of MgAlCe-LDH/β-Ni(OH)₂/Ni foam can be attributed to boosting exposed active sites, improving electronic interaction, and increasing charge transfer capacity resulting from the synthesis of MgAlCe-LDH on β-Ni(OH)₂/Ni foam. Implementing a two-electrode configuration for the MgAlCe-LDH/β-Ni(OH)₂/Ni foam, the total seawater splitting investigation exhibits 1.42 V cell voltage at a current density of 10 mA cm^-2 and 25 h long-term stability.