scholarly journals Investigating the Catalytic Active Sites of Mo/HZSM-5 and Their Deactivation During Methane Dehydroaromatization

2020 ◽  
Author(s):  
Ning Wang ◽  
Xinglong Dong ◽  
Lingmei Liu ◽  
Dali Cai ◽  
Jianjian Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Methane Dehydroaromatization ◽  
Catalytic Active Sites

scholarly journals Probing the Catalytic Active Sites of Mo/HZSM-5 and Their Deactivation during Methane Dehydroaromatization

2021 ◽  
Vol 2 (1) ◽  
pp. 100309
Author(s):  
Ning Wang ◽  
Xinglong Dong ◽  
Lingmei Liu ◽  
Dali Cai ◽  
Qingpeng Cheng ◽  
...  
Keyword(s):  
Active Sites ◽  
Methane Dehydroaromatization ◽  
Catalytic Active Sites

Active Sites and Induction Period of Fe/ZSM-5 Catalyst in Methane Dehydroaromatization

ACS Catalysis ◽  
2021 ◽  
pp. 6771-6786
Author(s):  
Yu Gu ◽  
Pingping Chen ◽  
Xiaohui Wang ◽  
Yuchao Lyu ◽  
Wanrong Liu ◽  
...  
Keyword(s):  
Induction Period ◽  
Active Sites ◽  
Methane Dehydroaromatization

scholarly journals Ultrasound-Assisted Preparation of Mo/ZSM-5 Zeolite Catalyst for Non-Oxidative Methane Dehydroaromatization

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Heidy Ramirez-Mendoza ◽  
Mafalda Valdez Lancinha Pereira ◽  
Tom Van Gerven ◽  
Cécile Lutz ◽  
Ignacio Julian
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Active Sites ◽  
Chemical Properties ◽  
Successful Implementation ◽  
Metal Dispersion ◽  
Zeolite Framework ◽  
Dispersed Catalysts ◽  
Methane Dehydroaromatization ◽  
Ultrasound Assisted

The activity and selectivity of Mo/ZSM-5, benchmarking catalyst for the non-oxidative dehydroaromatization of methane, strongly depend on the cluster size, spatial distribution, and chemical environment of the Mo-based active sites. This study discloses the use of an ultrasound-assisted ion-exchange (US-IE) technique as an alternative Mo/ZSM-5 synthesis procedure in order to promote metal dispersion along the zeolite framework. For this purpose, a plate transducer (91.8 kHz) is employed to transmit the ultrasonic irradiation (US) into the ion-exchange reactor. The physico-chemical properties and catalytic activity of samples prepared under the said irradiation procedure and traditional impregnation (IWI) method are critically evaluated. Characterization results suggest that US neither affects the crystalline structure nor the particle size of the parent zeolite. However, US-IE promotes molybdenum species dispersion, avoids clustering at the external fresh zeolite surface and enhances molybdate species anchoring to the zeolite framework with respect to IWI. Despite the improved metal dispersion, the catalytic activity between catalysts synthesized by US-IE and IWI is comparable. This suggests that the sole initial dispersion enhancement does not suffice to boost the catalyst productivity and further actions such ZSM-5 support and catalyst pre-conditioning are required. Nevertheless, the successful implementation of US-IE and the resulting metal dispersion enhancement pave the way toward the application of this technique to the synthesis of other dispersed catalysts and materials of interest.

scholarly journals Facile Synthesis of Uniform Mesoporous Nb2O5 Micro-Flowers for Enhancing Photodegradation of Methyl Orange

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3783
Author(s):  
Jian-Qing Qiu ◽  
Huan-Qing Xie ◽  
Ya-Hao Wang ◽  
Lan Yu ◽  
Fang-Yuan Wang ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Active Sites ◽  
High Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Flower Structure ◽  
Electron Microscopies ◽  
Bet Method ◽  
One Step ◽  
Catalytic Active Sites

The removal of organic pollutants using green environmental photocatalytic degradation techniques urgently need high-performance catalysts. In this work, a facile one-step hydrothermal technique has been successfully applied to synthesize a Nb2O5 photocatalyst with uniform micro-flower structure for the degradation of methyl orange (MO) under UV irradiation. These nanocatalysts are characterized by transmission and scanning electron microscopies (TEM and SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) method, and UV-Vis diffuse reflectance spectroscopy (DRS). It is found that the prepared Nb2O5 micro-flowers presents a good crystal phases and consist of 3D hierarchical nanosheets with 400–500 nm in diameter. The surface area is as large as 48.6 m2 g−1. Importantly, the Nb2O5 micro-flowers exhibit superior catalytic activity up to 99.9% for the photodegradation of MO within 20 mins, which is about 60-fold and 4-fold larger than that of without catalysts (W/O) and commercial TiO2 (P25) sample, respectively. This excellent performance may be attributed to 3D porous structure with abundant catalytic active sites.

Active sites of the methane dehydroaromatization catalyst W-ZSM-5: An HRTEM study

2008 ◽  
Vol 49 (1) ◽  
pp. 110-114 ◽  
Author(s):  
V. V. Kozlov ◽  
V. I. Zaikovskii ◽  
A. V. Vosmerikov ◽  
L. L. Korobitsyna ◽  
G. V. Echevskii
Keyword(s):  
Active Sites ◽  
Methane Dehydroaromatization
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