Tailored nanocomposites through the controlled reduction of metal nanoparticle-MOF templates.

The development of efficient catalysts is dependent on preparing materials, both metals and metal oxides, of controlled size, shape, and composition. The combination of metal nanoparticles (NPs) and semiconductor metal oxide supports provide highly active heterojunctions, which are known to promote chemical reactions. Recently, we have demonstrated how metal nanoparticles deposited on metal organic framework (MOF) architectures can be used as templates to prepare tailored metal/metal oxide composites; in this instance PdCu NPs deposited on the semiconductor Cu2O. These samples proved highly active for the hydrogenation of 4-nitrophenol, demonstrating significantly higher activity than our standard Pd/TiO2 catalysts. This proof-of-concept study has provided exciting preliminary results, which support the need for further investigation. The PdCu/Cu2O system alone has significant potential applications in photocatalysis, methanol synthesis, and formic acid decomposition. PdCu NPs and Cu2O have innate characteristics, which make them valuable catalytic materials, however, the synergy between the two systems, has the potential to provide further benefits. This project seeks to understand how these metal nanoparticle/MOF materials can be used to control the resultant metal/metal oxide interface and ultimately their catalytic properties. To answer these questions the project will rely heavily on the facilities at Diamond Light Source. The structures of the nanoparticles will be characterised using X-ray absorption fine structure (XAFS-B18,I20), whilst changes to the MOF architecture will be assessed using PDF (I15) and conventional diffraction techniques (I11). The potential of SAXS to understand the nature of these composites will also be explored. (I22, B21). Moreover, we will use operando methods to understand i) the formation of these materials and ii) how the structures of these tailored composites affect catalytic processes.