Investigation of plasmonic charge transfer in metallic NP-decorated photocatalyte
Abstract
This project addresses the surging global demands for clean water and a healthy environment for all. The research focuses on high-performance photocatalytic TiO2 nanostructures for the efficient photocatalytic treatment of contaminated water, including petroleum refinery wastewater and in particular the case of Nigerian delta regions where there are currently gas and oil leakages into the coastal regions and other sea and water pollutants. The target nanomaterials can be an efficient nanostructure in the form of TiO2 nanorods attached to/decorated with metallic nanoparticles functionalized to respond to a broad spectrum of light. The fabrication of the nanostructures is designed to achieve increased photoresponse in the visible spectral region to enable the use of natural sunlight in local communities where the provision of UV light source impose an additional burden in cost. The primary objective of the proposed method is to enable the innovative manufacturing of low-cost and environmentally friendly nanomaterials using locally sourced materials and plant pigments that contains relevant functional groups for the synthesis of the nanomaterials. The technique is based on the bio-oxidization/bio-reduction of metal-based salts by a modified hydrothermal wet-chemical method on the pre-grown seed layer. The fabrication of high-performance TiO2-based solar photocatalyst capable of both enhanced photocatalytic activity (necessary for efficient utilization in water treatment technology) and high structural robustness (necessary for reliability and durability) has rested in the difficulty to obtain a compromise between these two effects: high interfacial charge transfer processes requires high metal NPs loading, but high nanoparticle density leads to a structural weakness of the nanomaterials, which may lead to the collapse of the integrity of the interfaces and evolution of defects and traps for the photoexcited charges. Cognizant of this research problem, the applicant team is using a machine learning approach and density functional theory to model the relationship between structural connectivity between the metallic nanoparticles and TiO2 nanorods as well as the electronic structure of the TiO2?metal NPs. By changing the shape (and size) of the nanorods (and metallic nanoparticles), it will be possible to obtain TiO2-based materials that are structurally robust for efficient charge transfer between the nanocomposite, and at the same time, capable of high photo-response in the visible spectral region for utilization as photocatalyst under natural sunlight irradiation. This will lead to high-performance TiO2-based solar photocatalytic processes for solving contaminated water problems using inexpensive, readily available, and locally sourced materials. In addition, the aqueous environmental matrices of seawater and industrial wastewater pollutants will be studied using important physicochemical properties such as temperature, turbidity, colouring, etc. with reference to worldwide standardized determination methods. The kinetic and equilibrium data modeled using Langmuir?Hinshelwood (L?H) model and the temperature dependence of rate constant as described by the Arrhenius and transition state models; as well as the effect of temperature will be determined by the kinetic studies and the thermodynamic parameters (standard enthalpy, entropy, and Gibbs free energy change of activation). Results are to be presented for the kinetics of degradation of organic pollutants under different photocatalyst concentrations, reaction pH, and reaction temperatures.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 01, 2023
- Source ID
- W911NF2310259
Entities
People
- Fabian I Ezema
Organizations
- Army Contracting Command
- United States Army