Graphdiyne@NiOx(OH)y heterostructure for efficient overall water splitting

Abstract

Graphdiyne (GDY), a rising star of two-dimensional (2D) carbon materials consisting of unique sp-/sp²-cohybridized carbon atoms, has been demonstrated to be an ideal platform for developing efficient catalysts with high activity and long-term durability. In this work, a new GDY-based heterostructure of GDY@NiO_x(OH)_y was successfully synthesized and used as an efficient electrocatalyst for water splitting. The creative incorporation of GDY with NiO_x(OH)_y endows the heterostructure with unique advantages; for example, the mixed valent Ni species, the strong interactions between GDY and NiO_x(OH)_y, and the greatly enhanced charge transfer ability, which are significantly beneficial for enhancing the catalytic activity and long-term durability. When applied in alkaline OWS electrolysis, GDY@NiO_x(OH)_y||GDY@NiO_x(OH)_y exhibited a voltage of only 1.54 V to achieve 10 mA cm⁻², with robust stability over 100 h at 20 mA cm⁻², much better than most of the reported benchmark catalysts, making them outstanding among water-splitting electrocatalysts.