Catalytic performance and sulfidation behaviors of CoMo/Beta-MCM-48 catalysts prepared with citric acid for FCC gasoline hydroupgrading

2014 ◽  
Vol 22 (1) ◽  
pp. 127-135 ◽  
Author(s):  
Dinghong Qi ◽  
Aijun Duan ◽  
Zhen Zhao ◽  
Huadong Wu ◽  
Huili Fan ◽  
...  
Keyword(s):  
Citric Acid ◽  
Catalytic Performance ◽  
Fcc Gasoline

scholarly journals The Role of Nitrate on the Sol-Gel Spread Self-Combustion Process and Its Effect on the NH3-SCR Activity of Magnetic Iron-Based Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 314
Author(s):  
Xing Ning ◽  
Zhi-bo Xiong ◽  
Bin Yang ◽  
Wei Lu ◽  
Shui-mu Wu
Keyword(s):  
Nitric Acid ◽  
Citric Acid ◽  
Sol Gel ◽  
Nox Reduction ◽  
Combustion Process ◽  
Catalytic Performance ◽  
Metal Nitrate ◽  
Acid Sites ◽  
Complexing Agent ◽  
Nh3 Scr

Sol-gel spread self-combustion is the burning of the complexing agent in dried gel and the oxidant. Meanwhile, high temperature takes place during the combustion process, which is harmful to the pore structure of the catalyst. The nitrate from metal nitrate precursors as an oxidant could participate in the spread of the self-combustion process. Therefore, the influence of nitrate from metal nitrate on the spread self-combustion of an iron–cerium–tungsten citric acid gel and its catalytic performance of NOx reduction were investigated by removing nitrate via the dissolution of washing co-precipitation with citric acid and re-introducing nitric acid into the former solution. It was found that the removal of nitrate contributes to enhancing the NH3–SCR activity of the magnetic mixed oxide catalyst. The NOx reduction efficiency was close to 100% for Fe85Ce10W5–CP–CA at 250 °C while the highest was only 80% for the others. The results of thermal analysis demonstrate that the spread self-combustion process of citric acid dried gel is enhanced by re-introducing nitric acid into the citric acid dissolved solution when compared with the removal of nitrate. In addition, the removal of nitrate helps in the formation of γ-Fe2O3 crystallite in the catalyst, refining the particle size of the catalyst and increasing its pore volume. The removal of nitrate also contributes to the formation of Lewis acid sites and Brønsted acid sites on the surface of the catalyst compared with the re-introduction of nitric acid. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrates that both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms exist over Fe85Ce10W5–CP–CA at 250 °C with E–R as its main mechanism.

scholarly journals The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 226 ◽  
Author(s):  
Zakaria Sihaib ◽  
Fabrizio Puleo ◽  
Giuseppe Pantaleo ◽  
Valeria La Parola ◽  
José Luis Valverde ◽  
...  
Keyword(s):  
Citric Acid ◽  
Physicochemical Properties ◽  
Photoelectron Spectroscopy ◽  
Catalytic Performance ◽  
Morphological Properties ◽  
Molar Ratio ◽  
Hydrocarbon Oxidation ◽  
Total Oxidation ◽  
Propene Oxidation ◽  
X Ray

LaMnO3 (LM) catalysts with a molar ratio of citric acid (CA) to metal (La3+ + Mn2+) nitrates ranging from 0.5 to 2 (LM0.5 to LM2) were synthesized by the citrate sol–gel method with the aim of studying the effect of the citric acid ratio on the physicochemical properties and the catalytic performance in hydrocarbon oxidation. Structural and morphological properties of these catalysts were characterized by X-ray diffraction (XRD) and specific surface area (N2 adsorption) measurements, while the chemical composition was determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In the selected samples, additional characterizations were carried out by thermogravimetric and differential thermal analysis (TGA/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), temperature-programmed reduction by hydrogen (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the amount of citric acid used significantly influenced the TGA/DTA profile of gels along with the physicochemical properties of the catalysts. The XRD patterns are consistent with the perovskite formation as the main phase. The segregation of a small amount of Mn3O4, detected for molar ratios ranging between 0.5 and 1.5, suggested the formation of a slightly nonstoichiometric LaMn1−xO3 phase with a relatively high content of Mn4+. The catalytic performance was evaluated in the total oxidation of two selected hydrocarbons, toluene and propene, which represent typical volatile organic compounds (VOCs). Typically, three consecutive catalytic cycles were performed in order to reach steady-state performance in toluene and propene oxidation. Moreover, the stability of the catalysts under reaction conditions was investigated through 24-h experiments at 17% of toluene conversion. The catalysts LM1.2, LM1.3, and LM1.5 showed the best catalytic performance in both hydrocarbon oxidations, well comparing with the Pd/Al2O3 used as a reference.

Effect of Methanol on Catalytic Performance of HY Zeolite for Desulfurization of FCC Gasoline by Alkylation

2012 ◽  
Vol 51 (18) ◽  
pp. 6320-6326 ◽  
Author(s):  
Rong Wang ◽  
Yonghong Li ◽  
Benshuai Guo ◽  
Hongwei Sun
Keyword(s):  
Catalytic Performance ◽  
Hy Zeolite ◽  
Fcc Gasoline

Support effect on the catalytic performance of trimetallic NiMoW catalysts prepared with citric acid in HDS of dibenzothiophenes

2015 ◽  
Vol 250 ◽  
pp. 47-59 ◽  
Author(s):  
J. Arturo Mendoza-Nieto ◽  
Fernando Robles-Méndez ◽  
Tatiana E. Klimova
Keyword(s):  
Citric Acid ◽  
Catalytic Performance ◽  
Support Effect

scholarly journals Liquid deposition modification of nano-ZSM-5 zeolite and catalytic performance in aromatization of Hexene-1

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yujun Fang ◽  
Xiaofang Su ◽  
Wei Wang ◽  
Wei Wu
Keyword(s):  
Physical Adsorption ◽  
Fixed Bed ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Fuel Oil ◽  
Fcc Gasoline ◽  
Deposition Amount ◽  
Strong Lewis Acid ◽  
Liquid Deposition

The Olefin aromatization is an important method for the upgrade of catalytic cracking (FCC) gasoline and production of fuel oil with high octane number. The nano-ZSM-5 zeolite was synthesized via a seed-induced method, a series of modified nano-ZSM-5 zeolite samples with different Ga deposition amount were prepared by Ga liquid deposition method. The XRD, N2 physical adsorption, SEM, TEM, XPS, H2-TPR and Py-IR measurements were used to characterize the morphology, textural properties and acidity of the modified ZSM-5 zeolites. The catalytic performance of the Hexene-1 aromatization was evaluated on a fixed-bed microreactor. The effects of Ga modification on the physicochemical and catalytic performance of nano-ZSM-5 zeolites were investigated. The Ga species in the modified nano-ZSM-5 zeolites mainly exist as the form of Ga2O3 and GaO+, which provide strong Lewis acid sites. The aromatics selectivity over Ga modified nano-ZSM-5 zeolite in the Hexene-1 aromatization was significantly increased, which could be attributed to the improvement of the dehydrogenation activity. The selectivity for aromatics over the Ga4.2/NZ5 catalyst with suitable Ga deposition amount reached 55.4%.

scholarly journals A citric acid-assisted deposition strategy to synthesize mesoporous SiO2-confined highly dispersed LaMnO3 perovskite nanoparticles for n-butylamine catalytic oxidation

RSC Advances ◽  
2019 ◽  
Vol 9 (15) ◽  
pp. 8454-8462 ◽  
Author(s):  
Huawei Chen ◽  
Yanran Yang ◽  
Qing Liu ◽  
Mifen Cui ◽  
Xian Chen ◽  
...  
Keyword(s):  
Citric Acid ◽  
Catalytic Oxidation ◽  
Catalytic Performance ◽  
Highly Dispersed ◽  
Mesoporous Sio2 ◽  
Perovskite Nanoparticles

A citric acid-assisted deposition strategy was applied to synthesize mesoporous SiO2-confined highly dispersed LaMnO3 perovskite nanoparticles with optimum catalytic performance and N2 selectivity.

Oxidative Dehydrogenation of Cyclohexane over Mg-V-O Catalysts Prepared via Citriate Complexation

2011 ◽  
Vol 284-286 ◽  
pp. 692-696
Author(s):  
Mei Jin ◽  
Ping Lu ◽  
Guo Xian Yu
Keyword(s):  
Citric Acid ◽  
Oxidative Dehydrogenation ◽  
Active Sites ◽  
Metal Cations ◽  
Active Phase ◽  
Catalytic Performance ◽  
Dehydrogenation Of Cyclohexane ◽  
Ft Ir ◽  
Catalytic Active Phase ◽  
Magnesium Vanadates

Oxidative dehydrogenation of cyclohexane was studied over three pure Mg-V-O catalysts, which are Mg3(VO4)2, Mg2V2O7and MgV2O6, respectively. Catalysts were prepared via citric acid complexation and characterized by N2-adsorption, XRD, FT-IR, NH3-TPD and H2-TPR techniques. Among the pure magnesium vanadates, Mg3(VO4)2has the isolated active sites, weakly basic surface and lower reducibility of the metal cations, and could be recognized as the catalytic active phase. Mg3(VO4)2catalyst exhibited a better catalytic performance, on which a cyclohexene selectivity of 41.5% at cyclohexane conversion of 15.5% was obtained.

Sign in / Sign up

Export Citation Format

Share Document