Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Applied Physics | en_US |
| dc.contributor.advisor | Huang, Haitao (AP) | en_US |
| dc.contributor.advisor | Yang, Ming (AP) | en_US |
| dc.creator | Qiu, Haifa | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/13511 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Theoretical understanding and rational engineering of ferroelectric barium titanate-based electrocatalysts for water splitting | en_US |
| dcterms.abstract | Hydrogen production from water electrolysis using renewable energies is promising for net zero emission by 2050 to address global energy, climate, and environmental crises. Developing low-cost and efficient electrocatalysts of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to replace noble-based ones for water splitting is central to achieving the above goal. In recent years, ferroelectric (FE) materials have attracted increasing attention for piezo/pyro/photocatalytic water splitting due to switchable spontaneous polarization to overcome the Sabatier limit potentially. Among them, FE BTO shows the merits of low cost, eco-benignity, structure tunability, and well-defined structure. However, the water electrolysis of FE BTO has been less studied, and theoretical understanding and rational engineering need to be improved. Herein, using first principles DFT-based approaches, we comprehensively study the effects of FE polarization states, biaxial strain, transitional-metal (TM) doping on electrocatalytic HER/OER activity of FE BTO, and established structure/feature-activity correlation. | en_US |
| dcterms.abstract | We disclose that HER activity on TiO2-terminated FE BTO is tunable by adjusting the polarization state. Among the out-of-plane/in-plane polarization states, the latter is the most conducive toward HER. Hydrogen adsorption free energy is intimately related to surface oxygen p band center, with the in-plane polarized BTO being optimal, presumably because of in-plane surface dipole-dipole interaction. An HER catalytic cycle, driven by periodic strain, is proposed to overcome the Sabatier limit. | en_US |
| dcterms.abstract | We unravel the effect of biaxial misfit strain on the thermodynamic phase stability of FE BTO thin film at room temperature and the activity of HER and OER. By using self-consistent anharmonic lattice dynamics, the strain-induced phase sequence is determined such that the tensile strain favors forming in-plane polarized aa phase while the compressive one favors forming out-of-plane polarized c phase, with the former tensile strained aa phase showing optimal HER activity owing to proper electronic oxygen 2pz or titanium dz2 band center. In addition, the OER overpotential of tensile strained FE BTO is significantly reduced thanks to weakened oxygen intermediate adsorption. | en_US |
| dcterms.abstract | We investigate the TM doping effect on the HER activity of FE BTO and screen out the favorable TM dopants for HER on BTO which are subject to oxygen chemical potential and polarization states. We identify intimate correlations between HER activity and electronic/structural fingerprints. We find that the early group TM-doped BTO showed higher synthesizability, which is tunable by changing the oxygen chemical potential. Likewise, the larger the TM atomic number, the stronger the hydrogen adsorption in most cases. Consequently, the early few TM dopants in each group show optimal HER activity, with the Mo-doped BTO surface being the most optimal for all polarization states. Also, the higher the antibonding center, the stronger the hydrogen adsorption. More importantly, we propose a novel descriptor of surface oxygen that can better describe HER activity trends than conventional band center. Intriguingly, the surface reactivity is also related to the FE distortion characterized by the effective polarization. Noteworthily, by machine learning analysis, important inherent features are identified such as the number of outer electrons of TM dopants and the initial polarization state of FE BTO. A robustly predictive machine learning model is established that can decently predict the HER activity of TM doped BTO. | en_US |
| dcterms.abstract | These findings contribute to the understanding of FE-based controllable catalysis by changing polarization states, provide novel insights into rational strain engineering of FEs, and lay a foundation for the insights, rational design, and accelerated discovery of TM-doping of FE catalysts for catalysis and beyond. | en_US |
| dcterms.extent | ix, 184 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2024 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.LCSH | Hydrogen as fuel | en_US |
| dcterms.LCSH | Water -- Electrolysis | en_US |
| dcterms.LCSH | Piezoelectric materials | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | open access | en_US |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/13511