The excellent photocatalytic performances of silver doped ZnO nanoparticles for hydrogen evolution

Abstract

Ag based ZnO photocatalyst materials were prepared by facile, quick and inexpensive combustion method followed by calcinations at 700 °C for 3 h. The resulted nanoparticles were characterized using XRD, UV–Vis DRS, SEM, BET, FTIR, XPS, EDX and PL spectroscopy. The XRD analysis of silver doped ZnO (SZO) nanoparticles confirmed hexagonal wurtzite structure of ZnO with minimum crystal size about 19 nm. The doping of Ag in ZnO crystal lattice successfully suppressed the crystal growth of ZnO nanoparticles evidenced by XRD results. The DRS and PL spectra studies revealed that Ag doped ZnO nanoparticles showed absorption in visible light region and charge recombination was efficiently suppressed respectively. The DRS spectra analysis indicated that photon energy band gap Eg for SZO nanoparticles were in the range of 3.27–3.33 eV and reduced with increase in Ag doping. As a novel photocatalyst, the photocatalytic activity for hydrogen evolution was tested by water splitting using ethanol as sacrificial agent under solar light irradiation. The optimal hydrogen evolution rate 805 µmol h−1 g−1 was shown by 6% SZO photocatalyst. This was nearly 54 times higher hydrogen evolution rate as compared to pure ZnO. The improved photocatalytic activity was attributed to small particle size, plasmon band, charge separation and increased surface area. This report clearly revealed the benefit of using Ag doped ZnO catalyst for higher photocatalytic hydrogen generation.