The transition to sustainable energy is crucial for defossilizing the transport sector, with hydrogen (H2) emerging as a viable option for carbon-free fuel. However, while H2 combustion primarily produces water vapor, it also generates nitrogen oxides (NOx) emissions and potential carbon-based emissions from lubricant combustion. To achieve zero impact emissions and to maximize the environmental benefits of H2, an efficient exhaust gas aftertreatment system (EATS) is crucial. This study characterizes various catalysts – including oxidation catalysts (OCs), selective catalytic reduction (SCR) catalysts, and NOx storage catalysts (NSCs) – under close-to-real exhaust conditions using a synthetic gas test bench (SGB). The results reveal that OCs with differing platinum loadings exhibit significant variations in performance. Specifically, the higher-loaded OC demonstrates a substantially lower light-off temperature and higher H2 conversion efficiency compared to the ultra-low loaded OC. Moreover, while SCR catalysts show high NOx conversion efficiencies, they form secondary emissions such as nitrous oxide (N2O). A combined catalyst approach derived from a V2O5-WO3-TiO2 and a Cu-SSZ-13 catalyst is used to enhance NOx reduction while minimizing secondary emissions. The NSC effectively stores NOx during lean operation and low exhaust gas temperature. The thermal decomposition can be utilized to empty the NOx storage under lean conditions. A H2-rich operation can be employed to reduce stored NOx, although this approach tends to result in the formation of secondary emissions. In summary, this study shows that achieving zero impact emissions requires minimizing not only NOx and H2 but also N2O formation to effectively reduce overall greenhouse gas emissions.