2D/2D NiAl LDH integrated graphitic carbon nitride with robust interfacial contact for driving photocatalytic hydrogen production

Abstract

Photocatalytic hydrogen production is promising for generating carbon-free energy through water splitting. Efficient photocatalytic materials with high photochemical efficiency are crucial for creating well-structured photocatalytic systems. Layered Double Hydroxides (LDHs) have gained significant scientific attention due to their unique electronic structure, compositional flexibility, and tunable band gap, which make them highly active for photocatalytic hydrogen evolution. However, the high surface energy of LDHs can lead to layer deactivation and reduce their efficiency as standalone photocatalysts. Herein, a novel design of two-dimensional (2D) g-C3N4 with 2D NiAl LDH to construct morphologically 2D/2D binary heterojunction composite with strong electrostatic interactions has been investigated. Different characterization techniques, such as XRD, FESEM, EDX, UV–Vis spectra, and PL were conducted to assess its photo-physical properties. The introduction of 15% NiAl LDH led to a significant increase in hydrogen production, reaching 28.13 µmol h−1, which is 3.75 and 9 times higher than pure g-C3N4 and NiAl LDH, respectively. The improved photocatalytic performance was attributed to the efficient charge transfer facilitated by the formation of Type-II heterojunction system. The interface junction observed in 2D/2D g-C3N4/NiAl LDH restricts charge recombination and extends its lifetime to carry out photocatalytic reactions. Furthermore, the effective integration of NiAl LDH onto g-C3N4 observed from FESEM and EDX prevents the deactivation of LDH nanoplates, supplying abundant reaction-active sites to expedite the photo-redox reaction. Significantly, the incorporation of transition metals, such as Ni and Al, into the LDH brucite layer enhances the optical properties, allowing for better utilization of light and further improving photocatalytic hydrogen production. This work provides valuable insights into the development of 2D/2D morphologically-engineered nanohybrids for driving photocatalytic hydrogen production.