Nanosized SSZ-13 was synthesized hydrothermally by applying N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH) as a structure-directing agent. In the next step, the quantity of TMAdaOH in the initial synthesis mixture of SSZ-13 was reduced by half. Furthermore, we varied the sodium hydroxide concentration. After ion-exchange with copper ions (Cu²⁺ and Cu⁺), the Cu-SSZ-13 catalysts were characterized to explore their framework composition (XRD, solid-state NMR, ICP-OES), texture (N₂-sorption, SEM) and acid/redox properties (FT-IR, TPR-H₂, DR UV-Vis, EPR). Finally, the materials were tested in the selective catalytic reduction of NO_x with ammonia (NH₃-SCR). The main difference between the Cu-SSZ-13 catalysts was the number of Cu²⁺ in the double six-membered ring (6MRs). Such copper species contribute to a high NH₃-SCR activity. Nevertheless, all materials show comparable activity in NH₃-SCR up to 350 °C. Above 350 °C, NO conversion decreased for Cu-SSZ-13(2–4) due to side reaction of NH₃ oxidation.

The strength of the acidic sites rules the catalytic cracking: reduced acidic strength is not compensated by an increased accessibility of the acidic sites.

Zeolite-based catalysts are globally employed in many industrial processes, such as crude-oil refining and bulk chemical production. In this work, the cracking of low-density polyethylene (LDPE) was thoroughly followed in a FTIR operando study to examine the catalytic efficiency of purely microporous zeolites of various textural characteristics. To provide complementary and valuable information on the catalytic activity of the zeolite studied, the thermogravimetric analysis results were compared with yields of the products generated under operating conditions. The reaction products were analyzed via GC–MS to determine the hydrocarbon chain distribution in terms of paraffin, olefins, and aromatics. The individual impact of textural and acidic parameters on catalytic parameters was assessed. The accumulation of bridging hydroxyls of high strength in the zeolite benefited the decrease in polymer decomposition temperature. Through a strategic comparison of purely microporous zeolites, we showed that the catalytic cracking of LDPE is dominated by the acidic feature inherent to the microporous environment.