Electrocatalytic applications of organic semiconductors

With the announcement of Nobel Prize in chemistry in 2000, organic semiconductors and conjugated structures have been used for various applications like organic solar cells (OSCs), organic light emitting diodes (OLEDs), organic field effect transistors (OFETs). Due to the common belief in their instability in solutions (both in organic and in aqueous) exploration of their activity as catalytic materials remains mainly unexplored. This study aims to explore catalytic properties of organic semiconductors with a heterogeneous approach. As a first step a wellknown organic semiconductor, polythiophene is used as backbone for the immobilization of metal complexes which are capable of reducing CO2 to further products. This combined with photoactive property of polythiophene enabled the photoelectrocatalytic reduction of carbon dioxide. Apart from fixing the catalyst on the electrode via polymerization, anchoring of the catalyst CuTPP-COOH for driving the photoelectrochemical reduction of O2 to H2O2 was also carried out. CuTPP-COOH supported on TiO2 NTs showed good stability over time and more importantly reduced dissolved oxygen to hydrogen peroxide in neutral pH with a rate of 13.4 g H2O2 / gCuTPP-COOH / h. This value is comparable to the well-known literature examples of ZnO and g-C3N4. In another approach H-bonded semiconductors, namely Quinacridone, Indigo and naphthalene diimide, were utilized as efficient carbon dioxide (CO2) capturing agents in organic solvents as well as in aqueous media. These compounds showed uptake capacities of 4.6 mmol.g-1 and 2.3 mmol.g-1 which are comparable to state-of-the-art amine based capturing agents (uptake capacity of 8 mmol.g-1).submitted by Dogukan Hazar ApaydinIn Zusammenarbeit mit dem Institut für Physikalische ChemieUniversität Linz, Dissertation, 2018OeBB(VLID)258196