Constructing Earth-abundant 3D Nanoarrays for Efficient Overall Water Splitting - A Review

Constructing nanoarrays is a promising way to achieve efficient overall water-splitting for H-2 production. At first, this paper introduces the significance of constructing nanoarrays for gas evolution reactions: Constructing electrocatalyst with nanoarray structure can provide superaerophobic surface, which can lower the bubble adhesive force and bubble size by forming a discontinuous triple phase contact line (TPCL), and that can facilitate the release of gas, while it can afford abundant active sites, and that can enhance the activity and stability for gas evolution reactions. Then, we review the activity (including <= 1.49 V), and stability (including >= 100 h) for overall water splitting in alkaline medium of various kinds of recently reported earth-abundant 3D nanoarray bifunctional electrocatalysts. Later, we review the efficient strategies such as constructing nanoarrays with doping metals/heteroatoms, bi- metallic/multi-metallic materials, metal oxides, metal phosphide/phosphate, metal nitrides, carbon, amorphous materials, metal chalcogenides (metal sulfides and selenides), coreshell/hetero/hollow structure, vacancies/defects, and well-matched electrode pair to achieve efficient overall water splitting. Then, we review the construction of earth-abundant nanoarray bifunctional electrocatalyst for efficient overall water splitting in acid medium. Finally, we discussed the gas separation in water electrolysis.