Platinum group elements study in automobile catalysts and exhaust gas samples.

Platinum-Group Elements (PGEs, i.e. platinum; Pt, palladium; Pd and rhodium; Rh) are extensively employed in the production of automotive catalytic converters to catalyze and control harmful emissions from exhaust fumes. But catalytic converters wear out over time and the emission of PGEs along with the exhaust fumes are nowadays known to be the main reason of the presence of PGEs in urban environments. PGEs contents were studied on three gasoline 3-way catalytic convertors with low, medium and high kilometers. PGEs emission factors via exhaust gases from Euro 3, 4, 5 and 6 gasoline and diesel vehicles, were monitored using catalytic converters. Results show variable content for PGEs for the three converters, in the ranges of 6-511, 0.5-2507 and 0.1-312 mg kg-1 for Pt, Pd and Rh respectively. PGEs contents in different catalyst supports show the replacement of Pt by Pd in more recent converters. Analysis of the exhaust gas shows that catalytic converters expel up to 36.5 ±â€¯3.8 ng km-1 of Pt, 8.9 ±â€¯1.1 ng km-1 of Pd and 14.1 ±â€¯1.5 ng km-1 of Rh. Higher emissions of PGEs have been observed by gasoline Euro 3 vehicle, possibly due to the older technology of motorization and of the catalytic converter in this vehicle. Euro 3 and 4 diesel vehicles seem to emit more PGEs during urban cycles. Emission of PGEs has been also observed during the cold start of the majority of vehicles which seems to be the result of incomplete combustion during the rise of temperature in the engine. Higher PGEs emissions were also observed during motorway cycles in newer (Euro 4 and 5) petrol and diesel vehicles, conceivably due to the greater combustion as the engine speeds up during this cycle.

Euro 6 Unregulated Pollutant Characterization and Statistical Analysis of After-Treatment Device and Driving-Condition Impact on Recent Passenger-Car Emissions.

This study aims to measure and analyze unregulated compound emissions for two Euro 6 diesel and gasoline vehicles. The vehicles were tested on a chassis dynamometer under various driving cycles: Artemis driving cycles (urban, road, and motorway), the New European Driving Cycle (NEDC) and the World Harmonized Light-Duty Test Cycle (WLTC) for Europe, and world approval cycles. The emissions of unregulated compounds (such as total particle number (PN) (over 5.6 nm); black carbon (BC); NO2; benzene, toluene, ethylbenzene, and xylene (BTEX); carbonyl compounds; and polycyclic aromatic hydrocarbons (PAHs)) were measured with several online devices, and different samples were collected using cartridges and quartz filters. Furthermore, a preliminary statistical analysis was performed on eight Euro 4-6 diesel and gasoline vehicles to study the impacts of driving conditions and after-treatment and engine technologies on emissions of regulated and unregulated pollutants. The results indicate that urban conditions with cold starts induce high emissions of BTEX and carbonyl compounds. Motorway conditions are characterized by high emissions of particle numbers and CO, which mainly induced by gasoline vehicles. Compared with gasoline vehicles, diesel vehicles equipped with catalyzed or additive DPF emit fewer particles but more NOx and carbonyl compounds.