Research projects within Tian Group

The research within the Tian Group revolves around molecular devices for artificial photosynthesis. Below you will find more information about each project.

Organic polymers have potential to obtain the high photocatalytic efficiency, since their structures and corresponding properties can be facilely tuned by constructing them with differing chromophoric building blocks. However, all polymers reported so far for proton reduction are hydrophobic, leading to unsatisfactory performance in pure water. For this reason, the addition of an organic solvent or much liquid electron/proton donor, such as MeOH or triethanolamine (TEOA), is desirable. We experimentally proved that making the organic polymer into nano scale dots (Pdots) can dramatically improve the photocatalytic performance of proton reduction in aqueous solution without addition of any organic solvent.

Relevant Publications:

1. Wang L., Fernández-Terán R., Zhang L., Fernandes D., Tian. L., Chen H., Tian H., Organic Polymer Dots as Photocatalysts for Visible Light-Driven Hydrogen Generation, Angew Chem Int Ed, 2016, 55 (40), 12306-12310.
2. Pati P., Damas G., Tian L., Fernandes D., Zhang L., Pehlivan I., Edvinsson T., Araujo C., Tian H. An experimental and theoretical study of an efficient polymer nano-photocatalyst for hydrogen evolution, Energy Environ. Sci., 2017,10, 1372-1376 
3. Liu A., Tai C., Hola., Tian H. Hollow Polymer Nanoparticles: Nature Mimicking Architecture for Efficient Photocatalytic Hydrogen Evolution, J. Mater. Chem. A, 2019, doi: 10.1039/C8TA12146J 
4. Liu A., Gedda L., Axelsson M., Pavliuk M., Edwards K., Hammarström L., Tian H. Panchromatic Ternary Polymer Dots Involving Sub-Picosecond Energy and Charge Transfer for Efficient and Stable Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc., 2021, 143, 7, 2875–2885

On the basis of study of p-type dye sensitized solar cells and organic photovoltaics, we are working on the immobilizaiton of catalysts on different photocathodes to realize light driven water splitting and CO2 reduction. In order to make the catalyst firmly immobilized on photocathode, click chemistry is used as a effective strategy to perform this work. We transplant this concept on NiO-based electrode as well as organic photovoltaic (OPV) electrodes. 

Relevant Publications:

1. Chen Y., Chen, H., Tian H., Immobilization of a cobalt catalyst on fullerene in molecular devices for water reduction, Chem. Commun., 2015, 51, 11508-11511.
2. Tian H., Molecular Catalyst Immobilized Photocathodes for Water/Proton and Carbon Dioxide Reduction, ChemSusChem 2015, 8, 3746.
3. Pati. P., Zhang, L., et al., Insights into the Mechanism of a Covalently Linked Organic Dye–Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices,  ChemSusChem, 2017, 10 (11), 2480-2495.
4. Huang J., Gibert M., et al., Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2reduction, Dalton Trans., 2018, 47, 10775-10783 

Instead of liquid redox couple, electron conductor materials have been adopted to undertake electron transfer between photocathode and counter electrode in photosensitizer-sensitized mesoporous semiconductor solar cells. Molecular dyes, perovskite as well as quantum dots have been used as photosensitizer in this study. Different electron transport materials have also been employed to improve the energy conversion efficiency.

Relevant publications: 

1. Tian, H., Xu, B., Chen, H., Johansson, E. M. J. and Boschloo, G., Solid-State Perovskite-Sensitized p-Type Mesoporous Nickel Oxide Solar Cells. ChemSusChem, 2014 7: 2150.
2. Zhang, L., Boschloo, G., Hammarström, L., Tian, H., Solid state p-type dye-sensitized solar cells: concept, experiment and mechanism. Phys. Chem. Chem. Phys., 2016,18, 5080-5085 
3. Tian L., Föhlinger J., et al., Ultrafast dye regeneration in a core–shell NiO–dye–TiO2 mesoporous film. Phys. Chem. Chem. Phys., 2018, 20, 36-40.
4. Tian L., Föhlinger J., et al., Solid State p-Type Dye Sensitized NiO-dye-TiO2 Core-Shell Solar Cells. Chem. Commun. 2018, 54, 3739-3742 
5. Xu B., Tian L., et al. Solution-processed nanoporous NiO-dye-ZnO photocathodes: Toward efficient and stable solid-state p-type dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells. Nano Energy 2019, 55, 59-64

Mesoporous semiconductors have surface defects, named surface states as well, which play significant and different roles in solar energy converstion and storage devices. Understanding the role of surface states of semiconductors is particularly imporant to tune the  properties of mesoporous semiconductors and therefore improve performance of the corresponding devices. 

Relevant Publications:

1. Tian L., Tyburski R., Wen C, Sun R., Abdellah M., Huang J., D’Amario L, Boschloo G., Hammarström L., Tian H., Understanding the Role of Surface States on Mesoporous NiO Films. J. Am. Chem. Soc. 2020, .DOI: 10.1021/jacs.0c08886