Chapter 3 - Photocatalytic oxygen evolution reaction for energy conversion and storage of functional nanomaterials

Abstract

Ceria (CeO2) is an exciting alternative noble metal catalyst, because it has the ability to release and absorb oxygen in the redox system and function as an oxygen buffer. In this study, heterostructured catalysts consisting of CeO2/CdO nanocomposites were successfully synthesized by hydrothermal method in the presence of sodium hydroxide as a reducing agent from cerium nitrate and cadmium nitrate as a precursor that was then evaluated for its photocatalytic activity in the degradation of Rhodamine-B (RhB) synthetic dye. Ce:Cd nanoparticles were made up of Ce–O and Cd–O bonds confirmed by Fourier transform infrared spectroscopy. Synthesis temperature and pressure, during hydrothermal reactions, plays a critical role in controlling the shape, size, oxygen vacancy concentration, and low temperature reducibility in CeO2-based nanocomposites. The lattice constants and oxygen vacancy concentrations of ceria nanoparticles also depend upon the concentration of hydroxide ion, which leads to better morphology at low temperature and pressure. Further, the photocatalytic performance of the synthesized nanoparticles was monitored by photocatalytic degradation (PCD) of RhB synthetic dye under UV light irradiation. To get maximum PCD efficiency, we used H2O2 for the generation of excess reactive oxygen species (ROS). In addition, to explore and develop better catalysts and units for practical applications in this chapter we give an overview of ROS process along with the standard parameters to evaluate performance.