Prof. Dr.-Ing. Elias Klemm was appointed full professor of Heterogeneous Catalysis and Chemical Technology at the University of Stuttgart in 2009. Prior, he was 5 years full professor of Chemical Technology at the University of Chemnitz. He worked for 2 years as process engineer at Degussa AG (now EVONIK) in Hanau in the field of chemical micro process engineering. From 1995 to 2001 he was leader of a research group on zeolite catalysis at the University of Erlangen-Nuremberg. Elias Klemm studied chemical engineering at the University of Erlangen-Nuremberg and got his Pd.D. in the field of heterogeneous catalysis in 1995. He received the Jochen-Block-Award of the DECHEMA Subject Division Catalysis and the Carl-Zerbe-Award of the German Society for Petroleum and Coal Science and Technology (DGMK). Since 2012 Elias Klemm is CEO of the European Nanoporous Materials Institute of Excellence (ENMIX), a non-profit research organization devoted to synthesis, characterization and application of nanoporous materials.
The electrochemical reduction of carbon dioxide into formate was studied using gas diffusion electrodes (GDE) with Sn as electrocatalyst in order to overcome mass transport limitations and to achieve high current densities. For this purpose a dry pressing method was developed for GDE preparation and optimized with respect to mechanical stability and the performance in the reduction of CO2. Using this approach, GDEs can be obtained with a high reproducibility in a very simple, fast and straightforward manner. The influence of the metal loading on current density and product distribution was investigated. Furthermore, the effect of changing the electrolyte pH was evaluated. Under optimized conditions the GDE allowed current densities up to 200 mA∙cm-2 to be achieved with a Faradaic efficiency of around 90% towards formate and a substantial suppression of hydrogen production (< 3%) at ambient pressure. At higher current densities mass transport issues come into effect and hydrogen is increasingly produced. The corresponding cathode potential was found to be 1.57 V vs. SHE.