Project Outline

Palladium metal plays a key role in a wide range of catalytic reactions that have huge societal impact through many fundamental industrial processes. Its use is predominantly based around the vast versatility of the metal and the large number of accessible oxidation states that it possesses, which consequently makes it highly suited to roles in catalytic scenarios involving oxidative reactions (e.g. automotive NOx/SOxcatalysis), hydrogenation and dehydrogenation reactions (e.g. pharmaceutical syntheses), carbon-carbon coupling chemistry (e.g. organic transformations, carbon nanotube formation), and electrochemical transformations (e.g. fuel cells). Unfortunately, the study of the quadrupolar 105Pd nucleus (I = 5/2) using the solid state NMR (SSNMR) technique is hampered by its modest natural abundance (~22%), low gyromagnetic ratio γ (-1.23 x 10⁷ radT^-1s^-1) and enormous quadrupole moment Q (~66 x 10^-30 m²); hence, the field of ¹⁰⁵Pd solid state NMR is completely unexplored and methodologies need to be formulated that will assist in the elucidation of meaningful data from the study of this nucleus. However, although still challenging, recent ¹⁰⁵Pd solid state NMR studies have demonstrated that Pd metal nanoparticle systems are able to be observed with a large upfield Knight shift of -3.07%, and a fundamental study of different heterogeneous Pd metal-based systems supported on a variety of materials needs to be established. A comprehensive understanding of these systems will be investigated by studying nuclei such as ¹⁰⁵Pd, ¹³C, ²⁷Al and ¹H, and these studies will be correlated with important physical factors such as particle size effects, particle shape effects, the influence of the support materials, oxidation state, bimetallic systems, interactions with organic reductants, and mechanisms of catalytic deactivation. In particular, since many Pd nanoparticle systems are stabilised with organic substrates on the surface, the characteristics of this surface interaction can be probed with the DNP (Dynamic Nuclear Polarisation) technique, thus permitting the intrinsic differences between the surface, sub-surface and bulk speciation to be identified. The DNP approaches that will be implemented in this project will focus on sensitivity enhancements achievable from conventional radical sources such as TEMPOL or TOTAPOL, and will also involve an investigation of the feasibility of enhancements being obtained from natural radical sources in the Pd metal.

Teaching

• I have demonstrated in 3rd year MPhys Physics laboratory sessions (Oct 2013- Dec 2013, Oct 2014- Dec 2014)