Despite their benefits, DOCs have some limitations. They are less effective in reducing nitrogen oxides (NOx), which are another major pollutant from diesel engines. To address this, DOCs are often used in combination with other emission control technologies such as Selective Catalytic Reduction (SCR) and Diesel Particulate Filters (DPFs). Additionally, the effectiveness of DOCs can be compromised by the presence of sulfur in diesel fuel, which can poison the catalyst.
