FCH JU Systematic, Material-oriented Approach using Rational design to develop break-Through Catalysts for automotive PEMFC

The SMARTCat project is part of the European Fuel Cells and Hydrogen Joint Undertaking, and the aim has been to develop new concepts and production methods of fuel cells for automotive applications. The consortium has built a new concept of electrodes based on new catalyst architecture (ternary alloyed/core-shell clusters) deposited on efficient conductive metal-oxide support. In order to enhance the fundamental understanding and determine the optimal composition and geometry of the clusters, advanced computational techniques have been used in direct combination with electrochemical analysis of the prepared catalysts. The use of deposition by plasma sputtering on alternative non-carbon support materials will ensure the reproducible properties of the catalytic layers. Well-defined chemical synthesis methods have also been used prior for defining the best catalysts. In addition, MEA preparation, testing, and MEA automated fabrication completes the new concepts of catalysts with a considerably lowered Pt content (e.g. <0.01 mg/cm2) on the alternative support. A final goal has been to deliver a competitive and industrially scalable new design of PEMFC suitable for automotive applications. SMARTCat has as key activities: * New and innovative electrodes using tri-metallic low Pt-content (0.01 mgPt/cm2, 0.05g/kW) based catalyst nanoparticles and nanostructured layers. * Corrosion resistant conductive oxide-based materials with conductivity in the range of 0.01 to 0.1 S/cm. * Upscaling high temperature membranes with proton conductivity >60 mS/cm at 40°C and >200 mS/cm at 180°C. * Enable to optimize and to automate the production of MEAs to achive a production of 60 MEAs/day. * Prove the viability of the new concept for automotive applications with MEA of 220 cm2 and 5000h of durability. * Techno-economic assessment. Since the start of the SMARTCat project June 1st, 2013, the project roadmap; website (http://smartcat.cnrs.fr); density functional theory (DFT) simulations of bi- and tri-metallic catalyst systems; simulations on Pt interactions with doped metal-oxide support; as well testing synthesis of tri-metallic catalyst; chemical and plasma sputtering synthesis of bimetallic catalyst; and computational modelling and synthesis of doped oxide-based materials as support have been successfully achieved in a interdisciplinary work between partners and different work packages. Among the main findings, SMARTCat major outputs are: 1. Experimental results on ternary catalysts (PtNiAu, PtCoAu and PtCuAu) fit very well with theoretical calculations/simulations. Thus, high activities were obtained with ternary catalysts, confirming the validity of the project strategy. The results have shown a tendency in the following order: Pt3NiAu > Pt50Ni17Au33> Pt3CoAu > Pt3CuAu > Pt70Pd15Au15. In those systems, Pt3NiAu is a very promising catalyst with which the project has achieved the target of Pt load <0.1g/kW. 2. Pure tin oxide has poor electronic conductivity (~2*10-6 S/cm) as compressed powder (5.6 MPa). Thus, doping of SnO2 has been done with different atomic level of Sb and Nb. Based on the computational and experimental conductivity results, it has determined that doping with 7 at.% of Sb are the best option to increase the electronic conductivity above 1 S/cm. Addition of 1.5 at% Nb was introduced to stabilize the structure and inhibit the observed Sb-diffusion out of the core of the particles. 3. One-step synthesis of Pt-catalyst particles on doped SnO2 support have been prepared by flame spray pyrolysis. Well dispersed 1 nm Pt-particles can be found on the SnO2-based support by applying this method, which could potentially reduce the required amount of Pt-catalyst (in wt%) as the active surface area becomes significantly larger. The results have been presented at international workshops in Trondheim and Oslo, at the MRS Fall Meeting 2016 in Boston and the European Fuel Cell Car Workshop in Orleans, France March 2017. Potential upscaling of this supported catalyst synthesis procedure is being considered in collaboration with European companies. 4. High temperature (up to 180°C) polymer membrane with a proton conductivity of 0.3 S/cm has been developed within the project. Monomer, polymer synthesis is well in hand (a 1 kg campaign), thin unreinforced film preparation and curing at lab scale (100 cm2) proceeds well. 5. Automate MEA production has achieved a manufacturing of 50 MEA per day. An optimization of MEA production by use of oxide based support materials have been investigated. The fuel cell performance is lower compared to MEAs with carbon based catalyst supports, however, the stability is superior. The mass transfer within the layers is found crucial for the performance, demonstrated by added 50 vol% carbon for enhanced mass transfer. Further optimizations is hence, required before the oxide based catalyst supports can be deployed for the fuel cell industries.

The present consortium will build a new concept of electrodes based on new catalyst design (ternary alloys/core shell clusters) deposited on a new high temperature operation efficient support. In order to enhance the fundamental understanding and determin e the optimal composition and geometry of the clusters (alloys, core-shell), advanced computational techniques will be used in direct combination with electrochemical analysis of the prepared catalysts. The use of deposition by plasma sputtering on altern ative non-carbon support materials will ensure the reproducible properties of nanoclusters and nanostructured catalytic layers. Plasma technology is now a well established, robust, clean, and economical process for thin film technologies. Well-defined che mical synthesis methods will also be used for quickly defining the best catalytic system prior to shaping/designing by using plasma technology. In view of automotive operation conditions, MEA preparation, testing, and automated fabrication will complete t he new concepts of catalysts and supports for delivering a competitive and industrially scalable new design of PEMFC for automotive applications. Theferore, the project SMARTCat is in perfect harmony with the targets and requirements of the call SP1-JTI-F CH.2012.1.5 New catalyst structures and concepts for automotive PEMFCs.