The Study of Nitride Semiconductors Decorated with Metal Nanoparticles for Hydrogen Generation and Co2 Reduction through Pec Reaction

Project: Research project

Project Details

Description

In this project, metal nanoparticles(MNPs) associating with gallium nitride (GaN) semiconductors grown on sapphire substrates will be prepared to be the working electrodes for the photoelectrochemical(PEC) reaction. The band-edge positions of GaN straddle the potentials of the reduction and oxidation of water which is suitable for photoelectrochemical electrolysis of water. However, its wide bandgap ( 3.4 eV) makes the absorption of visible light unavailable. In principle, the bandgap of InxGa1-xN decreases with an increase of the indium content, and it can absorb photons with longer wavelength. Based on our previous study, when the content of indium exceeds 25%, the great difference of basic properties between the InN and GaN results in the miscibility and the formation of defects during the growth of InxGa1-xN epitaxial films. Therefore, the InxGa1-xN with poor material quality is not suitable to serve as working electrodes under light illumination in electrolytes. Our previous studies have demonstrated that metal silver nanoparticles embedded in GaN metal-insulator-semiconductor UV photodetectors can effectively increase UV absorption and show significant absorption in the visible (450-650 nm) wavelength band. In this project, we propose to prepare MNPs on the GaN epitaxial films as the working electrodes to split water for generating hydrogen gas and reducing carbon dioxide in the PEC experiments. The GaN/MNPs heterostructures may exhibit surface plasmon and/or catalytic characteristics to allow the absorption of solar spectrum extending to visible region and/or the reduction of threshold potential for PEC reaction, respectively. The three-year project is planned in three successive subjects. In 1st year, we will focus on the subject of "The study of optical properties for MNPs with different dielectric capping materials formed on GaN". The target is to establish a reliable and feasible working electrode for subsequent PEC experiments. Based on the 1st year experience, the 2nd year, we will focus on the subject of " The characterization of GaN/MNPs working electrodes under illumination in the electrolytes". In this year, carbon dioxide is also added to the electrolytes so that not only hydrogen gas but also greenhouse gas (carbon dioxide) can be reduced during the reaction to convert it into formic acid or methanol to capture carbon dioxide. The 3rd year, we will focus on the subject of "The clarification of MNPs’ roles when they are embedded between the dielectric materials and GaN films and immersed in electrolytes during the PEC experiments”. The target is mainly to clarify that the MNPs will exhibit a catalytic or surface plasma effect in PEC experiments.
StatusFinished
Effective start/end date08-08-0109-07-31

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