In the future, low-temperature proton exchange membrane fuel cells (PEMFC) are expected to compete and eventually replace conventional internal combustion engines in the automotive industry. However, the most vital part of PEMFC -the electrocatalyst -still contains too high quantities of the critical raw material, i.e.platinum (Pt). The state-of-the-art approach of lowering the need for Ptas well as improving the sluggish oxygen reduction reaction (ORR)can be achieved by alloying it with other transition metals(preparation of Pt-M; M = Cu, Ni, Co...).
In the first part of the Dissertation,wefirstly tackle the stabilityissueof our previousgenerationof thePtCu3/C electrocatalyst viadoping the crystal structure with gold (Au).In order to bridge the gap between laboratory scale evaluation using thin film rotating disk electrode (TF-RDE) and the industrial membrane electrode assembly (MEA), we have developeda novel approach towards the well-known galvanic displacement (GD) methodusing so-called ‘’double passivation’’ mechanism. The method enables preparation of large quantities of high-performancesupported Pt‐M electrocatalysts which is crucial for faster development and commercialization of PEMFCs. The method is facile, green, energy efficient and highly reproducible. In addition, it offers great flexibility over the catalyst design such as the choice of the sacrificial metal (M), variation of the chemical composition of(Pt:M)alloy, variation of total metal loading (Pt+M) on carbon support or even variation of the carbon support itself.
In the second part, we try to improve the understanding of the developed PtCu3/C electrocatalyst using advanced characterization tools. For instance, usingin-situtransmission electron microscopy (TEM) heating, we show that a better understanding of the thermal annealingprocess can be achieved. On the other hand, usingthe electrochemical flow cell connectedto inductively coupled plasma mass spectrometry (EFC-ICP-MS), one cangain understanding ofthe similarities and differences of dissolutionof metals constituting the alloy (Pt and M). Using the obtained knowledge, we demonstrate a developmentof a CO-assisted ex-situchemical activation (ex-situCA) method in order to activate the PtCu3/C electrocatalyst prior to incorporation in the MEA. Lastly, we show that the optimized binary PtCu3/C electrocatalyst can exhibit a better performance than the conventional Pt/C reference cathode material also in the PEMFC relevant environment.
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