Plasmonic enhancement of nanostructured composites containing zif-67 for photoelectrochemical water splitting
File(s)
Author(s)
Ji, Chengyu
Type
Thesis
Abstract
Green Hydrogen (H2) is considered an ideal fuel source due to its high energy-per-mass content and its inherent clean and renewable characteristics. One of the artificial solar-to-hydrogen technologies is photoelectrochemical water splitting (PEC-WS). Hydrogen produced by photoelectrochemical water splitting cells is in its infancy but has great potential if device efficiency and stability challenges can be solved. This thesis presents strategies in materials engineering that aim to boost photoelectrochemical water splitting efficiency.
The photoelectrochemical water splitting process has three main steps: (i). light absorption and generation of electron-hole pairs; (ii). separation and migration of charge carriers; (iii). surface chemical reactions. In this study, the implementation of various strategies including plasmonic enhancement, construction of a p-n junction, and nanostructuring are applied to hematite photoanodes to boost solar fuel efficiency.
Photoanodes consisting of two functionalised materials including plasmonic-Metal-organic-flamework (MOF) (ZIF-67 nanoparticle/metal nanomushroom array photoanode), plasmonic-hematite (hematite@Ag nanoparticle/Au nanohole array photoanode), and MOF-hematite (hematite nanorod@ZIF-67 p-n junction photoanode) were experimentally investigated. The results were also considered within a FDTD (Finite-Difference Time-Domain) theorical framework to get insight of what factors play a role in enhanced device performance. The light absorption, charge separation and surface charge transfer efficiencies were improved with the incorporation of ZIF-67 and plasmonic nanostructures.
Inspired by the findings of boosted photocurrents in binary material systems, a ternary plasmon-MOF-semiconductor composite structure (hematite@Ag nanorod@ZIF-67 photoanode) was designed and fabricated. This ternary system showed highest performance among the four different material systems (three Binary systems, one ternary system) in this study. The function of the MOF and plasmonic nanostructures were investigated.
The work presented in this PhD study therefore expands our understanding of engineering strategies for photoelectrochemical water oxidation and paves the way for future design of efficient photoanodes with commercial viability.
The photoelectrochemical water splitting process has three main steps: (i). light absorption and generation of electron-hole pairs; (ii). separation and migration of charge carriers; (iii). surface chemical reactions. In this study, the implementation of various strategies including plasmonic enhancement, construction of a p-n junction, and nanostructuring are applied to hematite photoanodes to boost solar fuel efficiency.
Photoanodes consisting of two functionalised materials including plasmonic-Metal-organic-flamework (MOF) (ZIF-67 nanoparticle/metal nanomushroom array photoanode), plasmonic-hematite (hematite@Ag nanoparticle/Au nanohole array photoanode), and MOF-hematite (hematite nanorod@ZIF-67 p-n junction photoanode) were experimentally investigated. The results were also considered within a FDTD (Finite-Difference Time-Domain) theorical framework to get insight of what factors play a role in enhanced device performance. The light absorption, charge separation and surface charge transfer efficiencies were improved with the incorporation of ZIF-67 and plasmonic nanostructures.
Inspired by the findings of boosted photocurrents in binary material systems, a ternary plasmon-MOF-semiconductor composite structure (hematite@Ag nanorod@ZIF-67 photoanode) was designed and fabricated. This ternary system showed highest performance among the four different material systems (three Binary systems, one ternary system) in this study. The function of the MOF and plasmonic nanostructures were investigated.
The work presented in this PhD study therefore expands our understanding of engineering strategies for photoelectrochemical water oxidation and paves the way for future design of efficient photoanodes with commercial viability.
Version
Open Access
Date Issued
2023-03-16
Date Awarded
01/08/2023
License URL
Advisor
Xie, Fang
Riley, Jason
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)