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Development of novel, high Performance hybrid TWV/GPF Automotive afteR treatment systems by raTIonAL design: substitution of PGMs and Rare earth materials

Periodic Reporting for period 3 - PARTIAL-PGMs (Development of novel, high Performance hybrid TWV/GPF Automotive afteR treatment systems by raTIonAL design: substitution of PGMs and Rare earth materials)

Reporting period: 2018-10-01 to 2019-09-30

To date, three way catalytic converters (TWCs) have been established as the most effective engine exhaust after-treatment system. However, TWCs not only fail to address the issue of particulate matter (PM) emissions but are also the main industrial consumer of Critical Raw Materials (CRMs) mainly Platinum Group Metals (PGMs) and Rare Earth elements (REEs), with the automotive industry accounting for 65%-80% of total EU PGMs demand. The enforcement of new limits on PM emissions (EURO 6c/7) will require higher TWC performance, hence leading to further increase the CRMs content in autocatalysts.
Addressing the necessity of CRMs reduction in catalysis, PARTIAL-PGMs proposed an integrated approach for the rational design of innovative nanostructured materials of low/zero PGMs/REEs content for a hybrid TWC/Gasoline Particulate Filter (GPF) for automotive emissions after-treatment with continuous particulates combustion also focusing on identifying and fine-tuning the parameters involved in their preparation, characterization and performance evaluation under realistic conditions.

PARTIAL-PGMs proposed an integrated approach for the coherent development of smart and innovative nanostructured automotive post-treatment systems by integrating TWCs on GPF, capable to meet future regulations, with reduced PGMs and REEs, leading to development of 2nd generation GPFs (Fig.1b). The main advantage of the proposed hybrid configuration isits small volume compared to current after treatment systems (Fig. 1a), which impacts not only cost, but also performance by reducing TWC light-off time and cold start emissions. Additionally, the smaller size allows its better packing into the exhaust pipelines, especially in small vehicles. Furthermore, the new hybrid approach enables, unlike the Diesel PFs, the continuous combustion of particulates, exploiting the distinctive characteristics of gasoline engines.
The consortium initially defined the technical specifications for the design and the full scale synthesis of the combined GPF/TWC. Regarding the multiscale modelling the team focused on the prediction of the properties of various types of catalysts and on the DFT modeling of base reactions. Key objectives were to identify the predictive descriptors of the catalytic efficiency and to provide input for the ration synthesis of the catalysts. Additionally, the team simulated the performance and provided a tool for design and scale-up of the GFP/TWC that would allow the optimization of the full-size converter features (dimensions, shape, channels density, porosity, distribution of catalytic material etc.). In parallel the team tried to link the various models across different length scales. The main outcome was a proof of concept implementation of microkinetics into 3D microscale models of permeation-diffusion-reaction in the filter wall coated with a porous catalyst.
The synthesis team, based on the input from modelling activities, focused on the development of novel catalysts, while performance evaluation measurements were carried out using simulated feed gas composition. A large number of catalysts were prepared and evaluated. These results enabled the consortium to identify the most promising catalysts and to proceed with their optimisation, emphasizing also on their upscalability.
These outcomes were used for the design and the production of the full scale GPF/TWC prototypes. The consortium succeeded in the upscaling of the selected materials and finally 6 full scale prototypes were developed and evaluated using a novel engine exhaust canning system. In parallel coating studies were performed to determine the optimum coating parameters. Additional testing, as well as novel mathematical models, has been applied to provide further knowledge on coating process. Furthermore, the team was focused on providing fundamental understanding of GDI engine particulate matter and the structure of porous substrates for GPFs.
Trying to set up a business case for the commercialization of the novel GPF/TWC, Life Cycle Assessment (LCA) was essential to analyze, evaluate, understand and manage the environmental effects. The team also performed in vitro toxicity tests to assess the health effects of the proposed combined after treatment system. Additionally, the consortium studied the effective recovery of the recovery of CRMs from deactivated automotive catalysts and exploited the PGMs leaching process from raw deactivated catalysts.
Dissemination was implemented with oral and posters presentations in relevant events, as well as a relevant number of publications in scientific journals. The Summerschool “Novel Automotive Catalysts production – materials modelling and synthesis, characterisation, scale-up and industrial process” was organized in Albarella (IT) on 17-20 June 2019, and joint workshop “CRITICAL RAW MATERIALS REDUCTION IN CATALYSIS Academia meets industry, research results and future developments” with the parallel project CritCat was organized in Braga on 11-12 April 2019 in Braga (PT) within the Common Dissemination Booster Initiative. Both events were opportunities for networking and exchange on both scientific and societal implications of the project results.
PARTIAL-PGMs proposed an integrated approach for the coherent development of smart and innovative nanostructured automotive after-treatment systems by integrating TWCs on GPF, capable to meet future regulations, with reduced PGMs and REEs. The main achievements of the project up included: (i) the rational design of the nanomaterials through modelling, (ii) the synthesis of effective catalysts with low or no CRMs content and (iii) the effective production of GPF/TWC.
The rational design of nanomaterials within the framework of PARTIAL-PGMs is a very promising concept having significant environmental, economic and political importance. Based on multiscale modelling, the consortium provided answers to specific questions related to materials’ synthesis, while enabled the study of the mechanisms involved in nanoscale and led to the prediction of the catalytic performance of the materials. The rational design of nanomaterials proposed by PARTIAL-PGMs is expected to support the efficient replacement or minimization of CRMs use in after-treatment systems. On the other hand the development of novel materials and processes are expected to address the issue of poisonous gas emissions in automotive sector.
Thus, the implemented activities exhibit significant environmental, economic and political importance. Currently, there is a constantly increasing interest focus on controlling the emissions of pollutants from engines around the world. Combustion of fossil fuels is by far the dominant source of CO, NOx emissions and PMs. The novel TWC/GPFs can provide a solution on emissions control, allowing also the reduction of CRMs.
There are also important societal implications beyond the PARTIAL-PGMs project’s research and technical objectives. The developed innovative materials and processes will contribute to the improvement of the environment and the quality of life. As the PGMs supplies are quite limited, their effective replacement by low cost transition metals, will secure the undisturbed supply of the European industry with critical resources, eliminating problems that can be faced in the future, due to overexploitation or trade and political restriction.
Fig. 1 (a) Different installation approaches for the GPF on current after treatment systems, (b) Hyb