Fabrication and characterization of novel V, S co-doped Ta3N5 protected with PANI composite materials for hydrogen generation from light-driven water splitting

Abstract

BackgroundThe rising global demand for energy and the associated environmental problems calls for the rapid development of renewable and eco-friendly energy systems. Due to advantages like low cost, and high catalytic efficiency, V, S co-doped Ta3N5 protected with polyaniline (PANI) photocatalyst as a photocatalyst has attracted more and more attention. MethodsHerein, co-doped V@S-Ta3N5/PANI composite materials were synthesized by two different approaches. Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) were used to analyze the structural and morphological properties of the synthesized composites. In contrast, the optical properties were analyzed with the help of UV–Vis diffuse reflectance spectroscopy (DRS) techniques. Electrical impedance spectroscopy (EIS) and photoluminescence (PL) tests were used to investigate charge separation efficiency and the degree of recombination. Significant findingsAs a dopant, V and S were incorporated into the lattice of Ta3N5, where their presence as an intermediate between the valance and conduction band of Ta3Na5 narrowed down its band gap. These intermediate bands of the metal (V) and non-metal (S) dopant also exhibit superior efficiency in electron-hole pair separation and prevent their recombination, extending the period of the electron-hole pairs. As a sensitizer/protector PANI, a conducting polymer, acted as a covering agent for the doped Ta3N5 particles to develop the charge transfer efficiency for relocating the photogenerated electrons and holes to the photocatalyst surface. Remarkably, synthesized composites have a higher photocatalytic activity of 3.8-folds higher than pure Ta3N5 at 98.4 mmol g − 1 h − 1 for H2 generation.