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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - PROMETHEUS (Platinum gRoup MEtals saving by monoliTHos Efficient and disrUptive catalySt innovation)

Teaser

Summary

\"A catalytic converter is an emissions control device that converts toxic pollutants, present in automotive exhaust gas, to non-toxic pollutants by catalysing the required chemical reactions. Since 1981, due to the increasingly stringent legislation on vehicle emissions, the \"\"three-way\"\" catalytic converters have been introduced to gasoline engine vehicles, providing three simultaneous services:
1. Oxidation of carbon monoxide (CO) to carbon dioxide: 2CO + O2 â†’ 2CO2
2. Oxidation of unburnt hydrocarbons (CxH2x+2) to carbon dioxide: CxH2x+2 + [(3x+1)/2]O2 â†’ xCO2 + (x+1)H2O
3.Reduction of nitric oxide (NO) to carbon dioxide and nitrogen: 2NO + 2CO â†’ 2CO2 + N2

The catalytic converter comprises of three main parts; the catalyst â€“ the heart of the device, the monolithic support for the catalyst, and the metal casing. The catalyst contains a mixture of precious metal (Platinum Group Metals â€“ PGMs) fine particles, where the above-mentioned catalytic reactions occur. PGMs comprise 6 elements: Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Iridium (Ir), Osmium (Os), and Platinum (Pt). The utilization of PGMs in catalysts fabrication for automotive emission control devices -mainly Platinum, Rhodium and Palladium- has been the prime driving force for market demand growth in the recent years and no alternative materials exhibiting similar efficiency in toxic pollutants abatement have ever been introduced to the market. It is worth noting that 40% of Pt, 81% of Rh and 67% of Pd demand is allocated to autocatalysts fabrication. In 2015, PGMs supply was below demand by about 20 tonnes and it is forecasted to grow in the coming years due to the increasingly stringent legislation on automotive emissions and also, the current irreplaceability of PGMs in autocatalysts. According to the International Trade Centre, in 2015 the European autocatalysts market used 43 tonnes of Pt, worth â‚¬1.4 billion, for autocatalysts that classifies Europe as the worldâ€™s largest consumer of PGMs. At the same time, European primary PGMs production is insignificant; about 70% of the global production (160 tonnes) comes from South Africa and Russia.
The PROMETHEUS project represents a disruptive innovation aiming to demonstrate and for the first time introduce to the market a novel eco-friendly nano-structured automotive catalyst substituting at least 50%, of the PGMs, while keeping the same performance and reducing production cost and European PMGs expenses/imports and and reliance on PGM producers.
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Work performed

During the first year of the project, the Prometheus catalyst has been successfully synthesized in lab scale, has been scaled up to 3.5kg batch, tested for its catalytic activity and also, deposited onto the walls of ceramic monoliths. Catalytic activity tests were conducted in an in-house synthetic gas bench set up using exhaust simulation gas mixture. Under real driving conditions, the gas mixture composition is perturbed between slightly oxidizing (lean-burn) and slightly reducing (rich-burn) conditions, due to the utilization of the lambda (Î») sensor that measures the O2 concentration in the exhaust gas mixture and the fuel/air ratio is adjusted accordingly by the vehicle ECU. Commercial OEM Euro III, Euro IV and Euro V/VI catalytic converters were purchased and tested as benchmark.

Final results

A comparison between the catalytic activity of the developed Prometheus catalyst loaded with 15g/ft3 PGMs and the three benchmark catalysts (Euro III, IV and V/VI) versus temperature is shown in Figure 1 under rich- (left) and lean-burn (right) conditions that were selected based on the catalytic converter testing protocol by FIAT Research Center. As shown in Figure 1, the Prometheus catalyst loaded with 15g/ft3 PGM performed better that the commercial OEM Euro V/VI catalyst that is loaded with 101g/ft3. This remarkable result allows for PGM reduction rates even above 85% that is higher than initially expected.
A more detailed performance analysis is given in Table 1a and Table 1b for the case of rich- (left) and lean-burn (right) conditions respectively, in terms of the required temperature for reaching 50% conversion (T50) and the maximum efficiency obtained for a given pollutant over each catalytic converter case. As shown, under reducing (Î»=0.99) conditions, T50 near 220oC was recorded for the Prometheus catalytic converter loaded with 15g/ft3 of PGM for the abatement of CO and CH4, and T50 near 285oC for the reduction of NO. These values are ~35oC lower than those obtained for the OEM Euro V/VI benchmark catalytic converter for the case of CO and CH4 oxidation, and almost the same for NO reduction. Similar results were obtained under oxidizing (Î»=1.03) conditions, were the T50 for CO and CH4 oxidation in the 15g/ft3 PGM Prometheus was 60 and 90oC lower than the OEM Euro V/VI. Moreover, as shown in Tables 1a and 1b the performance of the Prometheus catalytic converter loaded with only 5g/ft3 PGMs is similar to the OEM Euro III catalytic converter that is loaded with 32g/ft3 PGM. The above experimental results reveal that all mentioned commercial benchmark EOM catalytic converters can be replaced by a Prometheus catalytic converter that is loaded with a significantly lower amount of PGMs, in the range between 5 and 15g/ft3.
Projectâ€™s next milestones include the synthesis of the Prometheus catalyst at a 100kg batch scale, the fabrication of 110 prototype converters with various PGM loadings and the real demonstration of the Prometheus catalytic converter on-board three (3) passenger vehicles by mid-2019. Apart from the significant reduction in the cost of the catalytic converter device, such a reduction in PGM loading will have a tremendous impact in Europeâ€™s PGM imports, expenses and reliance on PGM producing countries, maintaining at the same time the strict emissions legislation.