Influence of silver electrochemically deposited onto zinc oxide seed nanoparticles on the photoelectrochemical performance of zinc oxide nanorod films

Abstract

The present article examines the synthesis and characterization of zinc oxide nanorods grown on zinc oxide and silver nanoparticle seeds. Zinc oxide seeds were electrodeposited on a support of fluorine-doped tin oxide glass and heat-treated at 380°C. Silver nanoparticles were then deposited on this substrate, which was heat-treated at 160°C. Their presence was confirmed using ultraviolet–visible spectroscopy, by observing an absorption peak around 400 nm, corresponding to surface plasmon resonance. Growth of zinc oxide nanorods was achieved in a chemical bath at 90°C. The obtained films were analyzed by cyclic voltammetry, X-ray diffraction, and scanning electron microscopy. They consisted of zinc oxide with a Wurtzite-type crystal structure, arranged as nanorods of 50 nm. X-ray photoelectron spectroscopy exhibits peaks attributed to silver (0) and to the formation of silver oxide on the silver nanoparticle surface. In addition, two types of oxygen (O 1 s) were observed: oxygen from the crystalline network (O–2) and chemisorbed oxygen (–OH), for the seed and the nanorod films, respectively. The nanorods grown on zinc oxide seeds with silver deposits had a round shape and greater photoactivity than those grown without silver. This difference is attributed to the additional reflection that silver provides to the light reaching the film, thereby increasing the photogeneration from the charge carriers.

ZnO/TiO2/Ag2Se nanostructures as photoelectrocatalysts for the degradation of oxytetracycline in water

“…Before coating, the FTO conductive substrates (2.5 cm × 2.0 cm) were ultrasonically cleaned in 0.10 M NaOH, ultrapure water and acetone, being further rinsed with water. The preparation of ZnO NRs thin films onto the conductive side of FTO was made by modifying a previous procedure [47][48][49]. The nucleation of Zn(OH) 2 seeds was first studied by chronoamperometry in an electrolytic cell equipped with the FTO as the cathode, a Pt wire as the anode and Ag|AgCl (3 M KCl) as the reference electrode.…”

“…This caused the precipitation of Zn(OH) 2 at the cathode, which could be subsequently dehydrated to ZnO at 70 ºC [47,50,51]. Based on this finding, the chronoamperometric 7 deposition of Zn(OH)2 seeds was performed at a constant cathodic potential (Ecath) of -1.1 V vs Ag|AgCl for 180 s. The resulting hydroxide was then calcined at 400 ºC for 2 h, and the ZnO NRs were obtained by hydrothermal treatment at 90 ºC for 75 min upon immersion in the supernatant solution resulting from a 0.15 mM Zn(NO3)2•4H2O solution in 0.80 M NaOH [49].…”

Investigating the Influence of Precursor Concentration on the Photodegradation of Methylene Blue using Biosynthesized ZnO from Pometia pinnata Leaf Extracts

“…Synthesis conditions can modify the structure and morphology of ZnO so that its physical and chemical properties change. Different preparation methods produce various ZnO shapes, such as nanobelts, nanotubes, nanowires, nanoflowers, nanospheres, and nanorods 4 .…”