Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Institute of Textiles and Clothing | en_US |
| dc.contributor.advisor | Fei, Bin (ITC) | en_US |
| dc.contributor.advisor | Xin, H. John (ITC) | en_US |
| dc.contributor.advisor | Wong, Wai-yeung (ABCT) | en_US |
| dc.creator | Wang, Yidi | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/11705 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Enhancement of metal halide perovskites on stability and photocatalysis | en_US |
| dcterms.abstract | Metal halide perovskites (MHPs) capable of visible light-harvesting emerged as a new potential class of photocatalysts, spanning applications such as organic pollutant photodegradation, CO2 photoreduction, photocatalytic hydrogen evolution, and organic photosynthesis. MHP nanocrystals with tunable bandgaps were excellent candidates for photocatalysts owing to the fascinating optoelectronic properties, such as wide absorption ranging from UV to visible light, high charge carrier mobility, low recombination of electron–hole pairs, easy processing, and low cost. However, their instability of chemical structure due to the low formation energy had restricted their practicality in photocatalysis. To address this issue, three efficient strategies, involving ligands modification, polymer encapsulation, and MOF scaffolding, were developed to isolate MHPs from the ambient conditions. | en_US |
| dcterms.abstract | In the first system, a capping ligand aniline was introduced to modify MAPbBr3 (MPE) for the first time. In the aniline-capped M-PE (AM-PE), aniline with hydrophobic phenyl groups is bound closely to the surface of M-PE NPs due to the suitable steric hindrance, effectively avoiding the penetration of polar solvent molecules. The asprepared AM-PE exhibited a regular morphology and improved stability. After immersing in polar solvent acetone for 24 hours, AM-PE kept the structure integrity confirmed by TEM. Moreover, a highly enhanced photocatalytic performance was achieved by AM-PE for photodegradation of malachite green (MaG) than the naked MPE, which should be attributed to the excellent light-harvesting ability and improved chemical stability by aniline. | en_US |
| dcterms.abstract | In the second system, a polymer encapsulation method was employed by in-situ growing a thin layer (10 nm) of poly(norepinephrine) (PNE) on the surface of monodisperse M-PE NPs to address their poor chemical stability. The M-PE@PNE composites with stable chemical structures could stand with the severe environment such as high moisture, strong light, and polar solvents. The chemical interaction between M-PE and PNE was proved to contribute to the light-harvesting ability and photocatalytic performance. In the photocatalytic reactions, the organic pollutant MaG was degraded by M-PE@PNE under visible light, achieving a degradation rate of 81 % in less than 2 h, which was 4.5 times higher than pristine M-PE NPs. | en_US |
| dcterms.abstract | In the last system, a sandwich structure OM-PE@PbBrOH⊂ZIF-67 was successfully constructed by confining OM-PE@PbBrOH core@shell QDs in the cavities of porous ZIF-67 scaffold, to fulfill the dual-enhancement of stability and photocatalysis. With the protection of water-stable layer PbBrOH, the OM-PE@PbBrOH⊂ZIF-67 composites manifested enhanced photocatalytic performance in the aqueous solution of Methylene blue for 8 hours. The porous shell ZIF-67 not only provided the confinement effect on OM-PE@PbBrOH QDs, but also acted as the efficient charge transfer layer. With a systematical investigation by XPS, TRPL, DRS, and photoelectrochemical analysis, the OM-PE@PbBrOH⊂ZIF-67 composite was proved as the staggered-gap heterojunction with a p-n junction, presenting a feasible interfacial dynamic for dye degradation. | en_US |
| dcterms.abstract | In summary, this study explored the feasibility of dual-enhancement on stability and photocatalysis of metal halide perovskites, developed three efficient strategies for surface engineering involving ligand modification, polymer encapsulation, and MOF scaffolding, and provided the mechanism analysis of the three models explaining the corresponding optoelectronic properties. Our work opened new possibilities of modifying the intrinsic properties and providing the functional diversification of MHPs. More importantly, the three surface engineering strategies reported in this work could be generalized for constructing the dual-enhancement models in other perovskite-based engineering fields. Therefore, the work presented here inspired a promising perspective for the development of stable perovskite photocatalysts with desirable photocatalytic efficiency. | en_US |
| dcterms.extent | xxv, 198 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2022 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.LCSH | Metal halides | en_US |
| dcterms.LCSH | Perovskite materials | en_US |
| dcterms.LCSH | Photocatalysis | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | open access | en_US |
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