Graphdiyne Coupled with g‐C3N4/NiFe‐Layered Double Hydroxide, a Layered Nanohybrid for Highly Efficient Photoelectrochemical Water Oxidation

Recently discovered graphdiyne (GDY) is a unique two‐dimensional (2D) planar structure with a high‐degree π‐conjunction network composed of sp and sp2 hybridized carbon bonds. GDY has high carrier mobility, rich chemical bond properties, and having a bandgap of ≈2.1 eV. In this study, for the first time, g‐C3N4/NiFe‐layered double hydroxide (LDH) is decorated by GDY to obtain a new strongly coupled ternary nanocomposite g‐C3N4/GDY/NiFe‐LDH, which has hierarchical mesoporous layered structure, large surface area, and broad visible spectrum absorption. These properties make g‐C3N4/GDY/NiFe‐LDH nanocomposite an outstanding candidate for photoelectrochemical water oxidation. Therefore, the new architecture is analyzed and achieve a high photocurrent density of 178.66 µA cm−2 by applying 1.4 V, a maximum incident photon‐to‐current efficiency (IPCE) of 3.59% at wavelength of 350 nm and 2.05% at 420 nm under standard AM 1.5G condition, which are also the best reported values in the literature. More interestingly, the proposed nanocomposite indicates a great durability, where there is nearly no dropping on the photocurrent under continuous illumination after 3600 s. This work suggests that additive engineering using GDY is an effective approach for the fabrication of efficient photoelectrochemical water oxidation devices. A ternary nanocomposite g‐C3N4/GDY/NiFe‐LDH is proposed with hierarchical mesoporous layered structure, large surface area, and broad visible spectrum absorption, which is an outstanding candidate for photoelectrochemical water oxidation.