Construct 3D NiCo-LDH/Cu2O p-n heterojunction via electrostatic self-assembly for enhanced photocatalytic hydrogen evolution

Hydrogen evolution of inorganic photocatalysts is currently a hot research topic. In order to prepare highly efficient catalysts for hydrogen evolution, p-n type heterojunctions were successfully constructed by closely combining p-type Cu2O and n-type NiCo-LDH with opposite electrical properties by a simple electrostatic self-assembly. In addition, because the positions of the two single catalysts NiCo-LDH and Cu2O Fermi levels are dissimilar from those of traditional p-n heterojunctions, the extremely high movement of Fermi levels forms a strong built-in electric field, which powerfully prevents the gradient diffusion of charge and facilitates the migration of intrinsic photocarriers. Furthermore, the flower cluster NiCo-LDH is composed of two-dimensional thin sheet structure, which has a large specific surface area and can prevent Cu2O agglomeration. Under the condition of using triethanolamine solution and eosin Y (EY) respectively as sacrifice reagent reducing agent and photosensitizer, the composite catalyst has reached 18332 μmol·g−1 in 5 h, which was increased by 8.5 times compared to the pure Cu2O. This research provides an innovative strategy to construct a heterojunction between a metal double-layer hydroxide and a non-noble metal oxide to realize an effective photocatalytic hydrogen production.