Spotlight on Large Surface Copper Cluster Role of Cu‐SAPO‐34 Catalyst in Standard NH₃‐SCR Performances

Abstract

In the present study, the catalytic role and behavior of different copper cluster configurations during NH 3 SCR, NO and NH 3 oxidation reactions will be studied in detail. For this purpose, two preparation methods were performed. The physico-chemical and surface properties were characterized by different techniques, such as XRD, ICP, N 2 ads/des, HR-TEM, XPS, NMR, ex-situ/in-situ DRIFT, NH 3 TPD and H 2 TPR, in order to evaluate the impact of copper incorporation method on redox active sites, and, as a consequence, to better understand the mechanism of the NH 3 SCR reaction. catalysts were then exposed to He for 30 min to remove all the physically adsorbed species before starting the desorption temperature program, which consisted of a ramp of 2°C · min À 1 until 500°C. Desorbed ammonia was analyzed by Fourier Transform Infrared (FTIR) spectrometer (NICOLET) equipped with a heated 2 m gas cell and a DTGS detector. 4 5 6 7 8

The Promotional Effect of Sulfates on TiO2 Supported Pt‐WOx Catalyst for Hydrogenolysis of Glycerol

“…[45] The band ranging from 1200 to 1300 cm À 1 is assigned to the NÀ H symmetric deformation vibration of NH 3 attached to the Lewis acid site, and this band only presents in Figure 5C, which demonstrates that there is no Lewis acid site on Pt/W/Ti. [46] The results of Figure 5B and C can be used to explain the much higher 1,3-propanediol selectivity of Pt/W/Ti, as reported by Zhou et al, Brönsted acid site is beneficial for the production of 1,3-propanediol, while Lewis acid site tends to produce 1,2propanediol, which will be further converted to n-propanol or ipropanol. [47] Figure 5D presents the comparative spectra of both Pt/W/Ti and Pt/WÀ S/Ti at 100°C.…”

“…As shown in Figure 5, the peak centering at around 1433 cm −1 is ascribed to the asymmetric deformation vibration of N−H in protonated NH 3 , indicating that both Pt/W/Ti and Pt/W−S/Ti possessed Brönsted acid sites [45] . The band ranging from 1200 to 1300 cm −1 is assigned to the N−H symmetric deformation vibration of NH 3 attached to the Lewis acid site, and this band only presents in Figure 5C, which demonstrates that there is no Lewis acid site on Pt/W/Ti [46] . The results of Figure 5B and C can be used to explain the much higher 1,3‐propanediol selectivity of Pt/W/Ti, as reported by Zhou et al, Brönsted acid site is beneficial for the production of 1,3‐propanediol, while Lewis acid site tends to produce 1,2‐propanediol, which will be further converted to n‐propanol or i‐propanol [47] .…”

Development of a Nonequilibrium Multisite Kinetic Model for NH3-SCR of NOx on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

“…The catalyst investigated in this study was laboratory synthesized from the support zeolite to its functionalization by copper ionic exchange incorporation, with a targeted elemental composition of 1 SiO 2 /6.7 Al 2 O 3 ·6.2 P 2 O 5 /161.3 H 2 O and 7.7 of TEAOH (35 wt % (C 2 H 5 ) 4 N­(OH); CAS 77-98-5), and a 1.5 wt % copper proportions. The support synthesis and corresponding functionalization are described in precedent studies. , Elemental composition and textural property results are displayed in Table SA in Supporting Information section where the close chemical and textural composition of the support and the catalyst are described under the assumed exchanged state (49%) …”

“…55 Hence, the main purpose of this study is to develop a nonequilibrium semidetailed kinetic model for NH 3 -SCR over Cu-CHA catalyst made in our laboratory and for the model to consider several active site configurations (Brønsted acid sites and redox active species), which were well characterized in our earlier studies. 56 This kinetic model with Cu-CHA catalysts will open new opportunities to better control the SCR process in the exhaust line, by evolution of the model in a neural network system, where optimized catalyst operating conditions can be sought and anticipated under real-time conditions. 57 The configurations, which give rise to different SCR behaviors, will be well described in the kinetic model via their corresponding sites.…”

“…The support synthesis and corresponding functionalization are described in precedent studies. 25,56 Elemental composition and textural property results are displayed in Table SA in Supporting Information section where the close chemical and textural composition of the support and the catalyst are described under the assumed exchanged state (49%). 28 2.2.…”