A DRIFTS study of the stability and reactivity of adsorbed CO species on a Rh/γ-Al2O3 catalyst with a very low metal content

Abstract DRIFTS experiments such as CO adsorption, CO-TPSR and CO+H2 were designated to study the effect of Fe promoter on the key steps of C2 oxygenates formation from syngas. The CO adsorption results demonstrated that Fe weakened CO adsorption and especially the bridging adsorption. It was found in CO-TPSR experiments that the catalyst with lower Fe loading is more easily dissociated while the ones with higher Fe loading own stronger hydrogenation activity. Moreover, it was observed by CO+H2 experiments that Fe plays a role in stabilizing the lineally adsorbed CO species and decreasing the CO desorption rate. The catalytic performance results indicated that when Fe content is 4wt. %, the selectivity of total C2 oxygenates is the highest, which was in accordance with the DRIFTS results.

Download Full-text

Heats of Adsorption of Linear and Multibound Adsorbed CO Species on a Pt/Al2O3 Catalyst Using in Situ Infrared Spectroscopy under Adsorption Equilibrium

Journal of Catalysis ◽

10.1006/jcat.2000.3030 ◽

2000 ◽

Vol 196 (1) ◽

pp. 115-125 ◽

Cited By ~ 56

Author(s):

Abdennour Bourane ◽

Olivier Dulaurent ◽

Daniel Bianchi

Keyword(s):

Infrared Spectroscopy ◽

Adsorption Equilibrium ◽

Heats Of Adsorption ◽

Adsorbed Co ◽

In Situ Infrared Spectroscopy ◽

Al2o3 Catalyst

Download Full-text

Local Structure of Pd1 Single Sites on the Surface of PdIn Intermetallic Nanoparticles: A Combined DFT and CO-DRIFTS Study

Catalysts ◽

10.3390/catal11111376 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1376

Author(s):

Nadezhda S. Smirnova ◽

Igor S. Mashkovsky ◽

Pavel V. Markov ◽

Andrey V. Bukhtiyarov ◽

Galina N. Baeva ◽

...

Keyword(s):

Absorption Band ◽

Large Distance ◽

Local Structure ◽

Co Adsorption ◽

Surface Plane ◽

Adsorbed Co ◽

Α Al2o3 ◽

Two Peaks ◽

Al2o3 Catalyst ◽

Intermetallic Nanoparticles

Local structure of Pd1 single sites on the surface of Pd1In1 intermetallic nanoparticles supported on α-Al2O3 was investigated by the combination of CO-DRIFTS spectroscopy and DFT. CO-DRIFTS spectra of PdIn/Al2O3 catalyst exhibit only one asymmetric absorption band of linearly adsorbed CO comprising two peaks at 2065 and 2055 cm−1 attributable to CO molecules coordinated to Pd1 sites located at (110) and (111) facets of PdIn nanoparticles. The absence of bridged or hollow-bonded CO bands indicates that multipoint adsorption on PdIn nanoparticles is significantly hindered or impossible. DFT results show that on (110) facet multipoint CO adsorption is hindered due to large distance between neighboring Pd atoms (3.35 Å). On (111) facet multipoint CO adsorption on surface palladium atoms is impossible, since adjacent Pd atoms are located below the surface plane.

Download Full-text

Chromium-Ruthenium Oxides Supported on Gamma-Alumina as an Alternative Catalyst for Partial Combustion of Methane

Catalysts ◽

10.3390/catal9040335 ◽

2019 ◽

Vol 9 (4) ◽

pp. 335 ◽

Cited By ~ 3

Author(s):

Tanakit Chomboon ◽

Weerit Kumsung ◽

Metta Chareonpanich ◽

Selim Senkan ◽

Anusorn Seubsai

Keyword(s):

Bimetallic Catalysts ◽

Lower Energy ◽

Operating Conditions ◽

Coke Deposition ◽

Catalyst Characterization ◽

Ruthenium Oxides ◽

Catalyst Screening ◽

Reactor Temperature ◽

The Stability ◽

Al2o3 Catalyst

Catalyst screening of γ-Al2O3-supported, single-metal and bimetallic catalysts revealed several bimetallic catalysts with activities for partial combustion of methane greater than a benchmark Pt/γ-Al2O3 catalyst. A cost analysis of those catalysts identified that the (2 wt%Cr + 3 wt% Ru)/γ-Al2O3 catalyst, denoted as 2Cr3Ru/Al2O3, was about 17.6 times cheaper than the benchmark catalyst and achieved a methane conversion of 10.50% or 1.6 times higher than the benchmark catalyst based on identical catalyst weights. In addition, various catalyst characterization techniques were performed to determine the physicochemical properties of the catalysts, revealing that the particle size of RuO2 became smaller and the binding energy of Ru 3d also shifted toward a lower energy. Moreover, the operating conditions (reactor temperature and O2/CH4 ratio), stability, and reusability of the 2Cr3Ru/Al2O3 catalyst were investigated. The stability test of the catalyst over 24 h was very good, without any signs of coke deposition. The reusability of the catalyst for five cycles (6 h for each cycle) was noticeably excellent.

Download Full-text

Novel bifunctional catalytic systems for the SCR of NOx using hydrocarbons as reductants: Step one, NO oxidation

Global NEST Journal ◽

10.30955/gnj.000142 ◽

2013 ◽

Vol 2 (2) ◽

pp. 159-166

Keyword(s):

Metal Content ◽

No Oxidation ◽

Significant Activity ◽

Pt Catalysts ◽

Catalytic Systems ◽

Ir Studies ◽

Ft Ir ◽

Oxidation Of No ◽

Al2o3 Catalyst ◽

Scr Of Nox

The oxidation of NO over Co-, Pt- and Rh-based catalysts was studied by combined catalytic activity and FT-IR studies. The activity of Co-, Pt- and Rh-based catalysts was measured in the presence and absence of H2O and SO2 in the feed. The activity studies showed that the support (Al2O3, TiO2, ZrO2) of Pt catalysts significantly affects the extent of the oxidation reaction, in addition to the metal content and calcination temperature over Co/Al2O3 catalyst. The highest activity was measured over 5 % Co/Al2O3 calcined at 450 °C, while Pt/ and Rh/Al2O3 catalysts exhibited significant activity (absence of SO2). The presence of 200 ppm SO2 inhibited irreversibly the NO oxidation mainly over Co/ and Rh/alumina. In the presence of 10 % H2O in the feed the activity of all catalysts weakly decreased, reversibly. FT-IR studies, over fresh Rh/Al2O3, showed the formation of Rh-NO+, Al-NO2 and Al-NO3 species, while over presulfated catalyst only the Rh-NO+ species was detected. Activity and FT-IR studies were used to propose a mechanism for the NO oxidation, in the presence and in the absence of SO2.

Download Full-text

Sintesis dan Karakterisasi Enkapsulat Katalis Nikel (II) pada Silika Mesopori Modifikasi

Jurnal Riset Kimia ◽

10.25077/jrk.v11i2.356 ◽

2020 ◽

Vol 11 (2) ◽

pp. 89-96

Author(s):

Admi Admi ◽

Fitria Ramadhani ◽

Syukri Syukri

Keyword(s):

Mesoporous Silica ◽

Metal Content ◽

Boron Trifluoride ◽

Vibration Band ◽

Leaching Test ◽

Modified Silica ◽

Solid Materials ◽

The Stability ◽

Mcm 41 ◽

Scanning Electron

Ni(II)-BF3/MCM-41 was synthesized for heterogeneous catalyst. The boron trifluoride modified mesoporous silica BF3/MCM-41 was studied to investigate its ability as supporting agent in heterogeneous catalysis system. For this purpose, the structural directing agent remaining in as-synthesis MCM-41 removed by solvent extraction. Surface modification of mesoporous silica MCM-41 with aniline and boron trifluoride was carried out. Then, the surface of boron trifluoride modified mesoporous silica was subjected to an encapsulation with Ni(II) ions. These solid materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic absorption spectroscopy (AAS). In the FTIR spectra of the modified silica mesoporous, the presence of vibration band >Si-O-B confirm the success of modification of support. While, the shifting of the vibration band >Si-O-Si< is considered an indication of the proof of Ni(II) species onto the modified mesoporous silica. From the SEM photograph, it can be seen that the morphology of the Ni(II)-BF3/MCM-41 tend to form aggregates of smaller particles. Based on measurement of metal content by AAS, it was known that the value of metal loading is 33%. While for the leaching test, Ni(II)-BF3/MCM-41 lost only 0.014 % of Ni metal. It indicates the stability of the interaction between the N(II) and support of the modified mesoporous silica.

Download Full-text