Hydrogen assisted ammonia SCR for removal of NOx from diesel engines

The market of the light-duty diesel-powered cars has grown during the last decade in Europe and also in the US. The reason for this is significantly less fuel consumption of diesel engines related to gasoline, which means better fuel economy and reduced CO2 emissions. In many countries there are also government incentives such as tax reduction for low CO2 emitting vehicles. The down side of diesel engines is the higher emission of harmful nitrogen oxides (NOx) and soot (Particulate matter, PM), as compared to gasoline vehicles with three-way catalysts (TWC). A distinctive feature of the diesel engine is that it is operating under non-stoichiometric air/fuel ratio with excess of air, so called lean conditions. TWCs used for gasoline cars cannot reduce NOx from the exhaust containing excess of oxygen and therefore other catalysts has to be used for removal of NOx from diesel exhausts.
Today there are two aftertreatment technologies available for lowering NOx emission from diesel-powered vehicles: selective catalytic reduction (SCR) with ammonia or urea (AdBlue) and lean NOx traps. SCR is the most robust and energy efficient of the two (energy efficiency = improved fuel economy). Urea-SCR is widely used for heavy-duty trucks to comply with Euro V. It is also implemented in a few light-duty vehicles. The stricter US tier 2, bin 5 (2009) and the up-coming and Euro 6 (2014) could see the demand for SCR on light-duty vehicles increase.
Light-duty diesel engines have exhausts with low temperature. This is tough for catalyst producers since the low temperature activity of SCR catalyst still is a challenge.
The results obtained through the project established that it is possible to increase NOx conversion at lower temperature using the catalyst investigated and optimized under the project.  
The results obtained in the project has positive impact to the society. It is the policy of the government to reduce NOx emission from diesel engines. As the efficiency of diesel engines becoming higher in response to lowering the CO2 emission, there is a definite need to find catalysts and systems that help reducing NOx emission at low temperatures. The findings of the project certainly contributes in this aspect.