Metal organic frameworks as catalysts for improving the efficiency of photocatalytic reactions 1=Energy 2=Catalysis

Plants have evolved to harvest solar energy and use the harvested energy to convert carbon dioxide and water into carbohydrates via photosynthesis. Inspired by the natural photosynthesis, artificial systems and devices using inorganic and organic materials to perform similar photochemical reactions has attracted considerable attention as a potential means of renewable energy production with no reliance on fossil fuels and no carbon dioxide emission. Photocatalytic water splitting forms hydrogen and oxygen which could be efficiently converted to electricity in fuels cells that has potential to energise the electric cars being built. In addition, photocatalytic reduction of CO2 not only removes CO2 from the atmosphere but also provides fuels that is much easier to store, distribute, and utilize within the existing energy supply infrastructure As a new family of inorganic-organic hybrid materials, metal-organic frameworks (MOFs) serve as an interesting platform to design and study artificial photosynthetic systems. MOFs can in principle contain photosensitizers and catalytic centers in a single solid and provide the structural organization to integrate the fundamental steps of artificial photosynthesis into a single material. The photoactivities of MOF catalysts in photo-induced CO2 reduction are still not comparable with those of inorganic semiconductors, which motivates us to further develop durable, low-cost, and high-performance MOF catalysts.
In this project, we will investigate the introduction of Light-harvesting complexes (Ir, Re, Ru complexes and porphyrin units) into the ligands of Zr-based MOFs (UiO-66). UiO-66 exhibits photocatalytic activity because of its ability to act like a semiconductor. This strategy can not only effectively promote light harvesting but also facilitate the charge separation in the energy conversion process, rendering MOFs as excellent photosensitizers in the photocatalytic process. MOFs. The pores of the MOFs will also be loaded with precious metal nanoparticles, e.g. platinum (Pt), as a co-catalyst.
Experimental studies will deliver fundamental understanding of the chemistry of the materials which will support development of improved technology. The experimental approach will build on our experience and expertise of design of catalysts with controlled composition, morphology and structure. Detailed catalyst characterisation, will provide essential information on catalyst structure and chemical properties. The catalytic results will feedback to the material synthesis in an iterative fashion to optimise and fine-tune the materials' properties for an efficient process. This project is in line with the UK's recently announced 'Clean growth' strategy and pave the way towards a carbon free future mobility. It is also in line with the EPSRC's theme of Physical sciences and the research area of 'Catalysis' which is in 'maintain' in EPSRC's portfolio.