scholarly journals Catalytic Elimination of Carbon Monoxide, Ethyl Acetate, and Toluene over the Ni/OMS-2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 581
Author(s):  
Ning Dong ◽  
Mengyue Chen ◽  
Qing Ye ◽  
Dan Zhang ◽  
Hongxing Dai
Keyword(s):  
Ethyl Acetate ◽  
Molecular Sieve ◽  
Space Velocity ◽  
Oxidation Of Co ◽  
Toluene Oxidation ◽  
Catalytic Activities ◽  
Catalytic Mechanisms ◽  
Ni Species ◽  
Synthesized Materials ◽  
Incorporation Method

The Ni-loaded cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts (xNi/OMS-2: x = 1, 3, 5, and 10 wt%) were prepared by a pre-incorporation method. Physicochemical properties of the as-synthesized materials were characterized by means of various techniques, and their catalytic activities for CO, ethyl acetate, and toluene oxidation were evaluated.The loading of Ni played an important role in improving physicochemical propertiesof OMS-2. Among all of the samples, 5Ni/OMS-2 exhibited the best catalytic activity, with the T90 being 155 °C for CO oxidation at a space velocity (SV) of 60,000 mL/(g·h), 225°C for ethyl acetate oxidation at an SV of 240,000 mL/(g·h), and 300 °C for toluene oxidation at an SV of 240,000 mL/(g·h), which was due to its high Mn3+ content and Oads concentration, good low-temperature reducibility and lattice oxygen mobility, and strong interaction between the Ni species and the OMS-2 support. In addition, catalytic mechanisms of the oxidation of three pollutants over 5Ni/OMS-2 were also studied. The oxidation of CO, ethyl acetate, and toluene over the catalysts took place first via the activated adsorption, then intermediates formation, and finally complete conversion of the formed intermediates to CO2 and H2O.

scholarly journals Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 713
Author(s):  
Zhidan Fu ◽  
Mengyue Chen ◽  
Qing Ye ◽  
Ning Dong ◽  
Hongxing Dai
Keyword(s):  
Ethyl Acetate ◽  
Active Oxygen Species ◽  
Oxygen Mobility ◽  
Oxidation Of Co ◽  
Toluene Oxidation ◽  
In Situ Drifts ◽  
Redox Couples ◽  
Ft Ir ◽  
Incorporation Method

Different Cu contents (x wt%) were supported on the cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) (xCu/OMS-2; x = 1, 5, 15, and 20) via a pre-incorporation method. Physicochemical properties of the OMS-2 and xCu/OMS-2 samples were characterized by means of the XRD, FT-IR, SEM, TG/DTG, ICP-OES, XPS, O2-TPD, H2-TPR, and in situ DRIFTS techniques, and their catalytic activities were measured for the oxidation of CO, ethyl acetate, and toluene. The results show that the Cu species were homogeneously dispersed in the tunnel and framework structure of OMS-2. Among all of the samples, 15Cu/OMS-2 sample exhibited the best activities with the T50% of 65, 165, and 240 °C as well as the T90% of 85, 215, and 290 °C for CO, ethyl acetate and toluene oxidation, respectively, which was due to the existence of the Cu species and Mn3+/Mn4+ redox couples, rich oxygen vacancies, good oxygen mobility, low-temperature reducibility, and strong interaction between the Cu species and the OMS-2 support. The reaction mechanisms were also deduced by analyzing the in situ DRIFTS spectra of the 15Cu/OMS-2 sample. The excellent oxygen mobility associated with the electron transfer between Cu species and Mn3+/Mn4+ redox couples might be conducive to the continuous replenishment of active oxygen species and the constantly generated reactant intermediates, thereby increasing the reactant reaction rate.

Enhanced catalytic performance of Cu- and/or Mn-loaded Fe-Sep catalysts for the oxidation of CO and ethyl acetate

2017 ◽  
Vol 25 (10) ◽  
pp. 1427-1434 ◽  
Author(s):  
Lisha Liu ◽  
Yong Song ◽  
Zhidan Fu ◽  
Qing Ye ◽  
Shuiyuan Cheng ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Catalytic Performance ◽  
Oxidation Of Co

Effect of Synthesis Duration on the Physicochemical Properties of Siliceous Mesoporous Molecular Sieve (Si-MMS)

2012 ◽  
Vol 326-328 ◽  
pp. 647-653 ◽  
Author(s):  
Anita Ramli ◽  
Sohail Ahmed ◽  
Suzana Yusup
Keyword(s):  
Physicochemical Properties ◽  
Pore Structure ◽  
Molecular Sieve ◽  
Mesoporous Material ◽  
Mesoporous Molecular Sieve ◽  
Diffraction Peaks ◽  
Adsorption Desorption ◽  
Synthesized Materials ◽  
Synthesis Duration ◽  
Mcm 41

Pure silica mesoporous molecular sieve (MMS) solid has been synthesized at 100°C by hydrothermal process. The effect of synthesis duration from 2 to 10 days has been investigated on the physicochemical properties of mesoporous molecular sieve. Samples were characterized by low angle XRD, N2adsorption-desorption and HRTEM analysis. XRD patterns of the as-synthesized samples showed four well-defined diffraction peaks corresponding to 100, 110, 200 and 210 planes. These peaks are the fingerprint characteristics of MCM-41 mesoporous material. The high intensity diffraction peaks were observed in 8-days sample that define the high ordering of the pores and long range order. N2adsorption-desorption results showed that all samples possessed a type IV isotherm having hysteresis loop of typeH1which is an identification of mesoporous material. Calcined samples exhibited high surface area i.e., 984-1036 m2g-1, pore volume i.e., 1.00-1.13 cm3g-1and average pore diameter i.e., 3.04-3.30 nm. A hexagonal pore structure was found in the synthesized materials by HRTEM analysis, which confirms that the synthesized materials are MCM-41. HRTEM analysis showed the effect of synthesis duration on the materials and found that 8-days sample exhibited highly ordered hexagonal pore structure like honeycomb structure. All the samples were calcined at 550°C to remove the template and to study the changes in the mesoporous framework. The results showed that the mesoporous structure remained intact after calcination at 550°C, indicating that the mesoporous materials exhibit high thermal stability.

Research on the Catalytic Activity of MnyCezOx/TiO2 for Ethyl Acetate Oxidation

2013 ◽  
Vol 781-784 ◽  
pp. 308-311 ◽  
Author(s):  
Xin Li ◽  
Wei Su ◽  
Qi Bin Xia ◽  
Zhi Meng Liu
Keyword(s):  
Catalytic Activity ◽  
Ethyl Acetate ◽  
High Activity ◽  
Fixed Bed ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Impregnation Method ◽  
Acetate Oxidation ◽  
Acetate Concentration ◽  
Molar Ratios

Manganese and cerium based catalysts with different Mn/Ce molar ratios prepared by impregnation method for ethyl acetate oxidation. The activity tests of the samples were performed in a fixed-bed reactor. The effect of gas hourly space velocity (GHSV) and ethyl acetate concentration on the catalytic activity of the catalyst were also investigated. The results showed that these catalysts had high activity for the catalytic oxidation of ethyl acetate, of which the catalyst Mn0.9Ce0.1Ox/TiO2exhibitedthe bestactivity, and the temperature required for 90% conversion of ethyl acetate was at 216 °C. The catalyst Mn0.9Ce0.1Ox/TiO2still maintained high activity in the range of GHSV (16,500 to 48,500 h-1) and ethyl acetate concentration (4526 to 7092 mg/m3). In additional, experiments for measuring stability of Mn0.9Ce0.1Ox/TiO2were carried out, and experimental results showed that the good stability of Mn0.9Ce0.1Ox/TiO2was kept after it has run for 25 hours.

scholarly journals Surface and Catalytic Properties of NiO–Fe2O3 Solids Supported on Al2O3

1996 ◽  
Vol 13 (5) ◽  
pp. 409-421 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
N.M. Deraz
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Properties ◽  
Unit Area ◽  
Surface Characteristics ◽  
Reaction Rate Constant ◽  
Oxidation Of Co ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Specific Surface Areas

A series of NiO–Fe2O3 catalysts supported on γ-Al2O3 was prepared. The effect of the NiO and Fe2O3 contents and the precalcination temperature on the surface and catalytic properties of the various solids has been investigated. The surface characteristics, viz. SBET, Vp and r, were determined using N2 adsorption conducted at –196°C. The catalytic activities of the various solids were studied using the oxidation of CO by O2 at temperatures in the range between 150°C and 400°C. The prepared solids were preheated in air at various temperatures between 400°C and 1000°C. The results obtained revealed that the SBET values of the different solids decrease progressively on increasing the precalcination temperature above 400°C due to sintering. The specific surface areas were also found to decrease on increasing both the NiO and Fe2O3 contents. The catalytic activities, expressed as reaction rate constant (k) and reaction rate constant per unit area (k), were found to decrease on increasing the precalcination temperature in the range 400–1000°C. Furthermore, the amounts of NiO and Fe2O3 in the different solids modified their catalytic activities in different manners.

scholarly journals Effect of Na2O Doping on the Surface and Catalytic Properties of the Mn2O3/Al2O3 System

1995 ◽  
Vol 12 (2) ◽  
pp. 119-128 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
S. Hammad
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Catalytic Properties ◽  
Xrd Analysis ◽  
Manganese Carbonate ◽  
Oxidation Of Co ◽  
Mechanical Mixing ◽  
Catalytic Activities ◽  
Specific Catalytic Activity ◽  
Catalytically Active

Manganese/aluminium mixed oxide solids having the formula 0.2MnCO3/Al2O3 were prepared by mechanical mixing of a known weight of finely powdered manganese carbonate and aluminium hydroxide. The solids obtained were treated with NaNO3 (0.75–6 mol%) solution and dried at 110°C, then calcined in air at 500°C and 800°C for 6 h. The phases produced were identified by XRD analysis. The surface properties (SBET, Vp and r̄) of the pure and doped solids were studied by using N2 adsorption at – 196°C and their catalytic activities were determined by studying the oxidation of CO by O2at 125–300°C. The results obtained reveal that pure and doped mixed solids preheated in air at 500°C and 800°C consist of Mn2O3 (partridgite) and a poorly crystalline γ-alumina. Doping with sodium oxide at 500°C and 800°C resulted in a small decrease (14–19%) in the SBET value of the treated solids. However, this treatment brought about a significant modification in the catalytic activity of the doped solids. Doping with 0.75% Na2O at 500°C led to an increase of about 30–50% in the specific catalytic activity which was found to decrease on increasing the percentage of Na2O above this limit, falling to values smaller than that measured for the undoped catalyst. Doping at 800°C led to a progressive decrease in the activity of the treated solid to an extent proportional to the amount of dopant present. The doping process at 500°C and 800°C did not modify the mechanism of the catalytic reaction but altered the number of catalytically-active sites contributing in the catalysis of CO oxidation by O2 without changing their energetic nature.

scholarly journals Self-Templating Synthesis of 3D Hierarchical NiCo2O4@NiO Nanocage from Hydrotalcites for Toluene Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 352 ◽  
Author(s):  
Dongdong Wang ◽  
Shuangde Li ◽  
Yingchao Du ◽  
Xiaofeng Wu ◽  
Yunfa Chen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rational Design ◽  
Space Velocity ◽  
Acid Sites ◽  
Step Method ◽  
Zeolitic Imidazolate Framework ◽  
Toluene Oxidation ◽  
Synthetic Strategy ◽  
Temperature Programmed ◽  
High Space

Rational design LDHs (layered double hydroxides) with 3D hierarchical hollow structures have generated widespread interest for catalytic oxidation due to the high complexity in shell architecture and composition. Herein, we reported a handy two-step method to construct a 3D hierarchical NiCo2O4/NiO nanocage. This synthetic strategy contains a partial in situ transformation of ZIF-67 (zeolitic imidazolate framework-67) into Co-NiLDH yolk-shelled structures following ethanol etching, and a structure-preserved transformation from Co-NiLDH@ZIF-67 to a biphase nanocage following calcination. CoNi-yh-T (varied reaction time and calcination temperature) nanocages were investigated systematically by Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), H2- temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and studied for toluene oxidation. The CoNi-6h-350 sample showed much higher activity with 90% toluene conversion (T90) at 229 °C at a high space velocity (SV = 60,000 mL g−1 h−1) than other catalysts (T90 >240 °C). Abundant surface high valence Co ions caused by the novel hierarchical nanostructures, together with adsorbed oxygen species and abundant medium-strength surface acid sites, played a key role for catalytic activities.

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