ERA-Chemistry: Novel Pt-poor catalysts for the electrocatalytic O2 reduction based on modified, nanostructured metal oxides

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The oxygen reduction reaction (ORR) is one of the most important electrocatalytic reactions due to its various applications, in particular in polymer electrolyte membrane (PEM) fuel cells, but also in oxygen sensors or, potentially, in metal air batteries. Until now, the best and most frequently used catalysts for the ORR are Pt-based materials, mainly carbon supported Pt or Pt-alloy nanoparticle catalysts. The high price for these materials is one of the main obstacles for the economically competitive introduction of PEM fuel cells. In the present project, we want to develop novel, Pt-poor or Pt-free oxide and oxycarbide/- nitride/oxycarbonitride early transition metal catalysts for the ORR, optimized with respect to activity, selectivity for H2O formation and corrosion stability under fuel cell relevant reaction conditions. This will be performed in a very systematic approach, via a deliberate tailoring of nanostructure, porosity and chemical composition of the catalyst and/or its support on the one hand correlated with its electrocatalytic performance on the other. This objective shall be reached by combining i) a synthetic approach to prepare mesoporous, high-surface area oxide materials of variable structure and composition, a very controlled approach of doping the material with carbon and nitrogen, the use of composite materials with a stable highly porous carbon backbone, which was recently developed by one of the applicants (Salzburg group), and ii) the use of a wide range of sophisticated electrochemical, microscopic and (in situ) spectroscopy methodic approaches to study electrocatalytic reactions under up to fuel cell relevant reaction conditions developed in the laboratory of the other applicant (Ulm group) in a highly iterative way. In combination, these measurements will provide detailed information on the correlation between materials properties and catalytic performance as well as mechanistic information, and thus provide a basis for further target-oriented improvement of the catalyst materials.