Universiteit Leiden

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Lezing

This Week's Discoveries | 22 oktober 2019

Datum
dinsdag 22 oktober 2019
Tijd
Locatie
Oort
Niels Bohrweg 2
2333 CA Leiden
Zaal
De Sitterzaal

First lecture

Title
Operator algebras: bridging between geometry and quantum theory

Speaker
Francesca Arici (MI) is an assistant professor and Veni Laureate working in the Analysis and Dynamical Systems group. She is particularly interested in applications of mathematics to theoretical physics. Her field of expertise, operator algebras, goes back to the work of von Neumann on the mathematical formulation of quantum mechanics, and as such it has lent itself to applications to problems where quantisation, symmetries and geometric invariants play a role.

Abstract
Starting from the work of von Neumann, the theory of operator algebras has provided an elegant and powerful setting for studying problems in mathematics and quantum theory. In particular, methods of noncommutative geometry and index theoretic invariants find applications in condensed matter theory, string theory and gauge theory. In this talk, I will review some recent results and applications.

Second lecture

Title
Fast electrocatalytic oxygen reduction by a Copper Catalyst: Towards efficient hydrogen peroxide production?

Speaker
Michiel Langerman (LIC) is a PhD student in the MCBIM and CASC research groups at the Leiden Institute of Chemistry (LIC). His work is focused around the elucidation of mechanisms involved in the electrocatalytic conversion of small molecules for renewable energy applications. The understanding of these principles of catalysis forms the basis for intelligent molecular catalyst design.

Abstract
The electrochemical oxygen reduction reaction (ORR) is essential for the use of hydrogen as a sustainable fuel, but currently requires high loadings of non-abundant platinum-based catalyst to perform the ORR in hydrogen fuel cells. Inspired by Laccase, a multicopper oxidase able to perform the ORR at a low overpotential, copper complexes have become interesting targets as non-precious metal catalysts for the ORR. Cu-tmpa is known to have good activity towards the ORR, but the mechanism has yet to be fully resolved. We demonstrate that the electrocatalytic reduction of O2 by the pyridylalkylamine copper complex [Cu(tmpa)(L)]2+ in neutral aqueous solution follows a stepwise 4e-/4H+ pathway, in which H2O2 is formed as a detectable intermediate and subsequently reduced to H2O. Hydrodynamic voltammetry measurements allowed for the catalytic regimes associated with these two separate catalytic reactions to be identified. Furthermore, the electrochemical study of the reaction kinetics has revealed a high turnover frequency of 1.5×105 s-1, the highest reported for any molecular copper catalyst thus far. These findings open new possibilities for the sustainable electrochemical synthesis of hydrogen peroxide.

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