Zeolite Framework Has a Bigger Controlling Effect than Transition-Metal Valence on Oxygen Replenishing Speed and Catalytic Activity

Utilization and replenishment of surface-active oxygens on the catalyst are critical to catalysis. Most reports have focused on the role of the catalytic center (i.e., the metal), and seldom attention has been paid to the carrier. In this work, we regulate the typical ZSM-5 (carrier) by desiliconization and dealumination before loading the Cu active species. The obtained catalysts are compared in the selective catalytic reduction of nitrogen oxide. The regulations have little influence on the crystal form (MFI), specific surface area (376.6–384.7 m2 g–1), micromorphology (200 nm), and catalytic processes (both Eley–Rideal and Langmuir–Hinshelwood). A combined method of experiment and theoretical calculation is used to characterize the oxygen replenishing speed. The zeolite after desiliconization is replenished by 0.63 × 10–6 mol min–1 gaseous O2 at 250 °C, which is faster than that (0.34 ×10–6 mol min–1) of the zeolite after dealumination. The adsorption energy of O2 (Eads) is −7.56 eV on the zeolite after desiliconization, which is smaller than that (Eads = 0.15 eV) on the zeolite after dealumination. O2 is inclined to be adsorbed by the zeolite framework with a lower isoelectric point. As a result, the zeolite after desiliconization converts 60% of NO (1000 ppm) at 250 °C, which is 25% higher than that of the zeolite after dealumination.