What is the end product if DEF is used in conjunction with an SCR Catalyst in a diesel exhaust system?

When DEF (Diesel Exhaust Fluid), which is a solution of urea and deionized water, is injected into the exhaust stream of a diesel engine and interacts with the SCR (Selective Catalytic Reduction) catalyst, a chemical reaction occurs. This process is designed to reduce nitrogen oxides (NOx) emissions, which are harmful pollutants.

The chemical reaction facilitated by the SCR catalyst transforms NOx into harmless byproducts. Specifically, DEF reacts with NOx in the presence of the SCR catalyst, resulting in the formation of nitrogen and water vapor. Nitrogen is the primary component of the atmosphere and is non-toxic, while water is also harmless.

So, nitrogen and water are indeed the end products of this reaction, making it the correct answer to the question asked.