# Pb/Pb3O4 Metal–Semiconductor Nanocomposite Obtained on 4A Zeolite—Optical and Structural Properties

## TL;DR

This paper describes a low-cost method to create Pb/Pb3O4 nanocomposites on zeolite 4A, which could be useful for UV photocatalysis due to their optical properties.

## Contribution

A novel low-cost synthesis method for Pb/Pb3O4 nanocomposites on zeolite 4A with potential UV photocatalytic applications.

## Key findings

- Pb/Pb3O4 nanocomposites have a core–shell structure with diameters of 5–25 nm.
- XPS analysis revealed a 4.8 eV binding energy difference between Pb 4f7/2 and Pb 4f5/2.
- The nanocomposites have a band gap of 4.50 eV, suitable for UV photocatalysis.

## Abstract

This work describes a controlled and low-cost synthesis
method
to obtain Pb/Pb3O4 nanocomposites using synthetic
zeolite 4A. The nanostructures obtained have a core–shell configuration
with 5–25 nm diameters. High-resolution transmission electron
microscopy (HRTEM), BF, high-angle annular dark-field annular scanning
transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray
spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible
(UV–vis) characterization techniques were used. Crystallographic
planes (111), (200), and (220) for the core and planes (110) and (211)
for the shell, corresponding to FCC and tetragonal structures for
Pb and Pb3O4, respectively, were determined
using HRTEM. The HAADF-STEM images allowed the analysis of intensity
contrast images proportional to the number of atoms. XPS spectral
analysis showed a 4.8 eV difference in binding energy between Pb 4f7/2 and Pb 4f5/2 for lead and lead oxide. EDS elemental
mapping, XPS, and UV–vis spectroscopy analyses revealed the
simultaneous presence of lead and lead oxide in the same structure.
The band gap obtained for the shell was determined to be 4.50 eV.
Consequently, Pb/Pb3O4 nanocomposites show a
higher response to high-energy photons, making them suitable for UV
photocatalysis applications.