Rational construction of 3D MoNi/NiMoOx@NiFe LDH with rapid electron transfer for efficient overall water splitting

• A novel 3D core-shell structed catalyst with metallic Mo-Ni nanoparticles was constructed. • The introduced Mo-Ni would make NiFe LDH nanosheets uniformly growth and provide a rapidly electron transfer channel. • The electrochemistry of 134 mV, 278 mV and 1.64 V (HER, OER, overall water splitting) at 100 mA cm –2 can achieve. It is still a great challenge to develop efficient and stable monolithic electrocatalysts with effective cost and abundant natural resources. Herein, a 3D structured NiFe layered double hydroxide (NiFeLDH) nanosheets rationally decorated on MoNi/NiMoO x nanowires array supported on Ni foam (MoNi/NiMoO x @NiFe LDH) are fabricated by an in-situ growth process is firstly reported. The results show that MoNi alloys can build a fast electron transport channel, thus improving the efficiency of the electrocatalyst. And the ultrathin NiFe LDH nanosheets would provide abundant exposed defects and catalytic active sites. A low overpotential (278 mV at 100 mA cm −2 ) and Tafel slope (44.7 mV dec −1 ) for oxygen evolution reaction, and overpotential (134 mV at 100 mA cm −2 ) and Tafel slope of 81.0 mV dec −1 for hydrogen evolution reaction in 1 M KOH can achieved. The overall water splitting system composed with 3D core–shell catalyst (MoNi/NiMoO x @NiFe LDH) and MoNi/NiMoO x nanowire arrays, which can obtain 100 mA cm −2 at a voltage of 1.64V, even superior to the benchmark of IrO 2 (+) // Pt/C (-).