Abstract The reaction path of the Cl 2 evolution reaction (CER) was investigated by combining electrochemical and spectroscopic methods. It is shown that oxidation and reconstruction of the catalyst surface during CER is a consequence of the interaction between RuO 2 and water. The state of the RuO 2 surface during the electrochemical reaction was analyzed in situ by using Raman spectroscopy to monitor vibrations of the crystal lattice of RuO 2 and changes in the surface concentration of the adsorbed species as a function of the electrode potential. The role of the solvent was recognized as being crucial in the formation of an oxygen‐containing hydrophilic layer, which is a key prerequisite for electrocatalytic Cl 2 formation. Water (more precisely the OH adlayer) is understood not just as a medium that allows adsorption of intermediates, but also as an integral part of the intermediate formed during the electrochemical reaction. New insights into the general understanding of electrocatalysis were obtained by utilizing the vibration frequencies of the crystal lattice as a dynamic catalytic descriptor instead of thermodynamic descriptors, such as the adsorption energy of intermediates. Interpretation of the derived “volcano” curve suggests that electrocatalysis is governed by a resonance phenomenon.
Das obige Zitat eröffnet Raum für Nachdenken über Sprache und Sprachmacht, und damit im weitesten Sinne über die Stimme: wem sie gegeben ist, der kann sich ausdrücken und Position beziehen; wem sie fehlt, dem wird nicht selten ein passiver Objektstatus zugewiesen. Die Frage nach der Stimme ist mithin eine Frage nach Autorität und Macht. Für die verbale Kommunikation nutzt der Mensch die menschliche Sprache; Tiere beherrschen diese nicht.2 In der Fiktion stellt sich das zuweilen anders dar: Literarische Tiere, auch „Texttiere“ genannt3, begegnen in der Literatur u. a. als sprechende, denkende, insgesamt bewusst handelnde Wesen4 – sie werden vermenschlicht.
The cover image shows how the reaction path of the Cl2 evolution reaction (CER) is investigated by combining electrochemical and spectroscopic methods, as reported by Schuhmann et al. on page 1897. Oxidation and reconstruction of the catalyst surface during CER is a consequence of the interaction between RuO2 and water. The solvent is crucial in the formation of an oxygen-containing hydrophilic layer, which is a key prerequisite for electrocatalytic Cl2 formation. New insights in the general understanding of electrocatalysis are obtained utilizing the vibration frequencies of the crystal lattice as a dynamic catalytic descriptor, instead of thermodynamic descriptors such as the adsorption energy of intermediates. Interpretation of the derived “volcano”-curve suggests that electrocatalysis is governed by a resonance phenomenon.
Abstract The performance of electrochemical reactions depends strongly on the morphology and structure of the employed catalytic electrodes. Nanostructuring of the electrode surface represents a powerful tool to increase the electrochemically active surface area of the electrodes. Moreover, it can also facilitate faster diffusive mass transport inside three‐dimensional electrodes. This minireview describes recent trends in the development of synthesis routes for porous nanostructured electrode materials and discusses the respective important electrocatalytic applications. The use of structure‐directing agents will play a decisive role in the design and synthesis of improved catalysts.
Chlorine evolution is one of the most important electrochemical reactions applied in industry. We present a method for the synthesis of chlorine evolution catalysts with improved performance. The performance increase results from the introduction of controlled mesoporosity into the pore system of Ru- and Ir-containing TiO2 catalysts by pore templating with micelles of amphiphilic block-copolymers. Micelle-templated TiO2-based catalysts were synthesized with loadings up to 15 wt % of either Ru, Ir, or a combination of both active metals. The catalysts’ walls are composed of nanocrystalline mixed oxides with rutile structure. The templated mesopores are about 10 nm in size and form an ordered cubic pore system with good pore connectivity. All studied catalysts are active in chlorine evolution. Adding templated mesoporosity doubles the catalyst performance at identical catalyst composition. The influences of film thickness, composition, and porosity of the developed catalytic coatings on the catalytic performance are discussed.
Faradaic selectivity of the chlorine and oxygen evolution (left) is linked to the spatial inhomogeneity of the surface reactivity of Ti–Ru–Ir mixed metal oxide catalysts.
