Surface engineering and photophysics of InP/ZnS quantum dots for photocatalytic application
Photocatalytic conversion of solar energy to chemical energy is regarded as a promising approach to address the energy crisis. In this thesis, we first employed InP/ZnS quantum dot as photocatalyst for H2 evolution application. Different ligands capped the surface of quantum dots to engineer the hole transfer rate and further modulate the photocatalytic performance. In this part, we elucidated the key role of ligands during the photocatalytic H2 evolution reaction. Secondly, Re photocatalyst was linked to InP/ZnS quantum dot covalently, which illustrated the multiple electron extraction efficiency tuned by the number of Re-catalyst tethered to one quantum dot. Multiple Re-catalyst attached to one quantum dot exhibited excellent photocatalytic methane evolution due to fast electron injection rate and achieving multi-electron extraction. This part of work provides a new strategy for optimal photocatalytic system design for the multi-electron transfer process. Finally, Re-catalyst was also tethered to InP/ZnS quantum dots by covalent bond, we explored the multi-electron injection affected by driving force which can be modulated by the size of quantum dots since the band alignment of quantum dots is size-tunable. Therefore, three different sizes of quantum dots were prepared as light absorbers, and the smallest quantum dot was shown satisfied multi-electron injection process due to large driving force, and further achiving photocatalytic reduction of CO2 to methane. This work indicated that photocatalytic product selectivity can be engineered by the driving force of multi-electron injection.
Principal Supervisor:
Senior Researcher Kaibo Zheng, DTU Chemistry
Co-supervisor:
Professor Jens Øllgaard Duus, DTU Chemistry
Examiners:
Associate Professor Susanne Mossin, DTU Chemistry
Associate Professor Haining Tian, Uppsala University
Senior Researcher Karel Zidek, Czech Academy of Sciences
Chairperson:
Professor Søren Kegnæs, DTU Chemistry