Presenter 1: Tim Duignan (Research Fellow, Zhao group, SoCE)

Title: Why is the real capacitance of carbon-based electrodes so low?

Abstract: Supercapacitors are a promising candidate for the next generation of energy storage devices, particularly when hybridised with battery type electrodes. These devices have a number of advantages over traditional batteries such as high-power densities and low-cost materials. However, their comparatively low energy density has limited their use to a few specific applications. These devices overwhelming rely on carbon-based materials for the electrodes due to their large specific surface areas. Intriguingly, the areal capacitance of the flat graphite surface is an order of magnitude lower than the areal capacitance of a metal surface such as silver. Therefore, if the origin of this difference could be understood and remedied the energy density of these devices could potentially be greatly increased. This difference has often been attributed to insulator like behaviour of the carbon with charge being stored inside the bulk of the electrode away from the surface leading to an internal voltage change. I will demonstrate using quantum mechanical calculation that this effect is relatively negligible and will explore various alternative hypotheses to explain the difference.


Presenter 2: Yuk Ping Chin (PhD student, Krenske group, SCMB) – PhD confirmation seminar

Title: Understanding the chiral induction mechanism of chiral phosphoric acid catalysts

Abstract: Asymmetric synthesis is a common method that is used in pharmaceutical synthesis to prepare enantiomerically pure molecules – molecules that only have one isomer of a chiral centre. In order to improve the yield and enantiomeric excess of the desired enantiomers, catalysts are commonly used. Catalysts that used in asymmetric synthesis also have the function to induce chirality to prochiral substrates. Among chiral induction catalysts, chiral phosphoric acids have gained popularity in recent years. However, chiral phosphoric acids’ chiral induction mechanism remains unclear from experimental results. With the aid of computational modelling, we are able to gain more insights into the chiral induction mechanism which will lead to the advancement of future catalyst design. Among many of the reactions using chiral phosphoric acid catalysts, Nazarov cyclisations have been chosen as a case study. This talk will present the results of quantum mechanical calculations to investigate their activation mechanisms reveal the chiral induction mechanism.


AIBN Seminar Room