Noncovalent interaction stabilizes the 2,4-Dinitrophenylhydrazone Derivatives over g-C3N4 surface to enhance optical properties: Synthesis, characterization, and DFT investigation

Abstract

Immobilization of organic compounds on semiconductor surface was recently exploited to enhance the semiconductor light absorption and photocatalytic performance. Here, synthesis of 2,4-Dinitrophenylhydrazone-benzaldehyde (DPHH), 2,4-Dinitrophenylhydrazone-2-thiophenecarboxyaldehyde (DPHS), 2,4-Dinitrophenylhydrazone-4-dimethylaminobenzaldehyde (DPHN) and 2,4-Dinitrophenylhydrazone-4-aminobenzoic acid (DPHB) was introduced and characterized with different spectroscopic techniques such as FT-IR and UV–Vis spectroscopy. The UV–vis absorption spectra of the hydrazone compounds were stabilized (red shifted) in polar solvents such as N,N-dimethylformamide (DMF) and acetonitrile (ACN). Density functional theory (DFT) was used to investigate the structures conformations and stabilizing forces. Doping of g-C3N4 nanosheets with 5% of the hydrazone derivatives decreases the optical band gap from 2.71 eV to 2.62 eV with DPHN derivatives. The DFT investigation coupled with reduced density gradient (RDG) show that hydrazone derivatives was stabilized on g-C3N4 by vdW forces. These results shows that the hydrazone derivatives could be potentially used as sensitizers for photocatalysis and solar cells systems.