Metal-Organic Framework-Derived Multidimensional Hierarchical Assembling Body with a Superhydrophilic and Superaerophobic Surface Toward Efficient Electrochemical Overall Water Splitting

The goal-oriented design of efficient and robust bifunctional catalysts represents an important endeavor toward overall water electrolysis. Herein, MOF-derived 2D nanosheet arrays loaded on a 3D porous Ni substrate are elaborately constructed, whose surfaces are densely populated with oriented 1D N, P dual-doped carbon nanotubes, wherein the ultrafine OD NiCoP nanoparticles are encapsulated on the tip (denoted as NiCoP-NPCNT-NF). Benefiting from the unique multidimensional hierarchical architecture, it can not only inherit the advantages of isolated building units but also possess a promising superhydrophilic and superaerophobic surface, thus facilitating close contact with the electrolyte and fast removal of gas bubbles. Experiments combined with theoretical calculation corroborate that the interface coupling between graphite carbon layers and NiCoP species can modulate the local electronic density, leading to moderate adsorption and desorption energy of various intermediates. Consequently, the optimized NiCoP-NPCNT-NF exhibits excellent electrocatalytic performances (53/248 mV at 10 mA cm(-2)) in alkaline media for cathode hydrogen evolution reaction and anode oxygen evolution reaction. Moreover, the assembled water electrolysis device only needs a much lower voltage (1.582 V) at 10 mA cm(-2), accompanied by robust operational stability for over 100 h. This study provides an innovative and available avenue to prepare MOF-derived catalysts for overall water electrolysis.

Automated summary

Efficient and robust bifunctional catalysts are crucial for overall water electrolysis. In this study, a multidimensional hierarchical architecture catalyst was constructed, showing excellent electrocatalytic performance for the hydrogen evolution reaction and oxygen evolution reaction in a water electrolysis device.