Effect of Cu and Cs in the b-Mo2C System for CO2 Hydrogenation to Methanol

Mitigation of Anthropogenic CO2 emissions possess a major global challenge for modern societies. Herein catalytic solutions are meant to play a key role. Among the different catalysts for CO2 conversion Cu supported on molybdenum carbide is receiving increasing attention. Hence, in the present communication we show the activity, selectivity and stability of fresh-prepared -Mo2C catalysts and compare the results with those of Cu/Mo2C, Cs/Mo2C and Cu/Cs/Mo2C in CO2 hydrogenation reactions. The results showed that all the catalysts were active and the main reaction product was methanol. The results showed that copper-cesium and molybdenum effectively interact and that cesium promoted the formation of metallic Mo. While, the incorporation of copper is positive to improve the activity and selectivity to methanol, the presence of Mo0 phase was detrimental for the conversion and selectivity. Moreover, the catalysts promoted by cesium underwent redox surface transformations during the reaction that diminished their catalytic performance. The molybdenum phase in Cu/Mo2C changes during reaction leading to metallic molybdenum and tuning the catalytic activity.

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Effect of Cu and Cs in the β-Mo2C System for CO2 Hydrogenation to Methanol

Catalysts ◽

10.3390/catal10101213 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1213 ◽

Cited By ~ 1

Author(s):

Ana Belén Dongil ◽

Qi Zhang ◽

Laura Pastor-Pérez ◽

Tomás Ramírez-Reina ◽

Antonio Guerrero-Ruiz ◽

...

Keyword(s):

Molybdenum Carbide ◽

Catalytic Performance ◽

Co2 Hydrogenation ◽

Main Reaction ◽

Main Reaction Product ◽

Present Communication ◽

Fresh Catalyst ◽

Global Challenge ◽

Hydrogenation Reactions ◽

Supported Molybdenum Carbide

Mitigation of anthropogenic CO2 emissions possess a major global challenge for modern societies. Herein, catalytic solutions are meant to play a key role. Among the different catalysts for CO2 conversion, Cu supported molybdenum carbide is receiving increasing attention. Hence, in the present communication, we show the activity, selectivity and stability of fresh-prepared β-Mo2C catalysts and compare the results with those of Cu/Mo2C, Cs/Mo2C and Cu/Cs/Mo2C in CO2 hydrogenation reactions. The results show that all the catalysts were active, and the main reaction product was methanol. Copper, cesium and molybdenum interaction is observed, and cesium promoted the formation of metallic Mo on the fresh catalyst. The incorporation of copper is positive and improves the activity and selectivity to methanol. Additionally, the addition of cesium favored the formation of Mo0 phase, which for the catalysts Cs/Mo2C seemed to be detrimental for the conversion and selectivity. Moreover, the catalysts promoted by copper and/or cesium underwent redox surface transformations during the reaction, these were more obvious for cesium doped catalysts, which diminished their catalytic performance.

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CVD Synthesis of Supported Molybdenum Carbide Catalyst and its Catalytic Activity for CO2 Hydrogenation.

KAGAKU KOGAKU RONBUNSHU ◽

10.1252/kakoronbunshu.21.1015 ◽

1995 ◽

Vol 21 (6) ◽

pp. 1015-1023 ◽

Cited By ~ 4

Author(s):

Toshihiro Miyao ◽

Masakuni Matsuoka ◽

Isao Shishikura ◽

Masatoshi Nagai

Keyword(s):

Catalytic Activity ◽

Molybdenum Carbide ◽

Co2 Hydrogenation ◽

Cvd Synthesis ◽

Supported Molybdenum Carbide

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Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽

10.3390/en14175506 ◽

2021 ◽

Vol 14 (17) ◽

pp. 5506

Author(s):

Daniel Carreira Batalha ◽

Márcio José da Silva

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Heterogeneous Catalysts ◽

Raw Materials ◽

Catalytic Performance ◽

High Specific Surface Area ◽

Biodiesel Production ◽

Molar Ratio ◽

Main Reaction ◽

High Catalytic Activity

Nowadays, the synthesis of biofuels from renewable raw materials is very popular. Among the various challenges involved in improving these processes, environmentally benign catalysts compatible with an inexpensive feedstock have become more important. Herein, we report the recent advances achieved in the development of Niobium-containing heterogeneous catalysts as well as their use in routes to produce biodiesel. The efficiency of different Niobium catalysts in esterification and transesterification reactions of lipids and oleaginous raw materials was evaluated, considering the effect of main reaction parameters such as temperature, time, catalyst load, and oil:alcohol molar ratio on the biodiesel yield. The catalytic performance of Niobium compounds was discussed considering the characterization data obtained by different techniques, including NH3-TPD, BET, and Pyr-FT-IR analysis. The high catalytic activity is attributed to its inherent properties, such as the active sites distribution over a high specific surface area, strength of acidity, nature, amount of acidic sites, and inherent mesoporosity. On top of this, recycling experiments have proven that most Niobium catalysts are stable and can be repeatedly used with consistent catalytic activity.

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Optimization of Calcination Conditions for Cu/ZnO/Al2O3-ZrO2 Catalyst

Catalysts ◽

10.3390/catal11080871 ◽

2021 ◽

Vol 11 (8) ◽

pp. 871

Author(s):

Nur Insyirah Zulkifli ◽

Nor Hafizah Berahim ◽

Noor Asmawati Mohd Zabidi ◽

Sara Faiz Hanna Tasfy

Keyword(s):

Response Surface Methodology ◽

Pore Volume ◽

Pore Diameter ◽

Catalytic Performance ◽

Hydrogenation Reaction ◽

Co2 Hydrogenation ◽

Bet Surface Area ◽

Co2 Conversion ◽

Zro2 Catalyst ◽

Central Composite

Promoted Cu/ZnO catalyst was synthesized on Al2O3-ZrO2 support. Effects of calcination conditions on the catalytic performance in a CO2 hydrogenation reaction were studied systematically using the response surface methodology (RSM). The application of RSM with rotatable central composite design (RCCD) for optimization on the influence of catalyst’s calcination variables on the CO2 conversion and methanol selectivity is presented. The calcination variables studied include temperature, A (181–518 °C), ramping rate, B (1–30 °C/min), and duration, C (1–7 h). From the RSM-generated model, the optimum calcination condition for this catalyst was 350 °C with 17.5 °C/min ramping rate for a 4 h duration. At the optimum calcination condition, the catalyst exhibited a Brunauer–Emmett–Teller (BET) surface area of 147 m2/g, a pore volume of 0.31 cm3/g, and a pore diameter of 8.1 nm.

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The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

Catalysis Science & Technology ◽

10.1039/c8cy02291g ◽

2019 ◽

Vol 9 (3) ◽

pp. 811-821 ◽

Cited By ~ 7

Author(s):

Zhao-Meng Wang ◽

Li-Juan Liu ◽

Bo Xiang ◽

Yue Wang ◽

Ya-Jing Lyu ◽

...

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Aerobic Oxidation ◽

Catalytic Performance ◽

Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

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Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Catalysts ◽

10.3390/catal11060735 ◽

2021 ◽

Vol 11 (6) ◽

pp. 735

Author(s):

Yuhao Zheng ◽

Chenghua Xu ◽

Xia Zhang ◽

Qiong Wu ◽

Jie Liu

Keyword(s):

Synergistic Effect ◽

Active Sites ◽

Intermediate Formation ◽

Active Phase ◽

Dissociative Adsorption ◽

Co2 Hydrogenation ◽

Chain Growth ◽

Co2 Conversion ◽

Light Hydrocarbons ◽

Active Centers

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

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Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽

10.3390/catal11010088 ◽

2021 ◽

Vol 11 (1) ◽

pp. 88

Author(s):

Diana García-Pérez ◽

Maria Consuelo Alvarez-Galvan ◽

Jose M. Campos-Martin ◽

Jose L. G. Fierro

Keyword(s):

Catalytic Activity ◽

Surface Area ◽

Catalytic Properties ◽

Catalytic Performance ◽

Major Influence ◽

Pt Catalysts ◽

Reduction Temperature ◽

Metal Dispersion ◽

Tungsten Oxides ◽

Supported Pt Catalysts

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.

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A diffusion anisotropy descriptor links morphology effects of H-ZSM-5 zeolites to their catalytic cracking performance

Communications Chemistry ◽

10.1038/s42004-021-00543-w ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Xiaoliang Liu ◽

Jing Shi ◽

Guang Yang ◽

Jian Zhou ◽

Chuanming Wang ◽

...

Keyword(s):

Catalytic Activity ◽

Catalytic Cracking ◽

Catalytic Performance ◽

Zeolite Catalysts ◽

Time Resolved ◽

Cracking Performance ◽

Morphology Effect ◽

Ft Ir ◽

The Difference ◽

Dynamics Simulations

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

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Immobilization of an Iridium(I)-NHC-Phosphine Catalyst for Hydrogenation Reactions under Batch and Flow Conditions

Catalysts ◽

10.3390/catal11060656 ◽

2021 ◽

Vol 11 (6) ◽

pp. 656

Author(s):

Henrietta Kovács ◽

Krisztina Orosz ◽

Gábor Papp ◽

Ferenc Joó ◽

Henrietta Horváth

Keyword(s):

Catalytic Activity ◽

Ion Exchange ◽

Heterogeneous Catalyst ◽

Aqueous Phase ◽

Levulinic Acid ◽

Flow Reactor ◽

High Catalytic Activity ◽

Flow Conditions ◽

Hydrogenation Reactions ◽

Excellent Selectivity

Na2[Ir(cod)(emim)(mtppts)] (1) with high catalytic activity in various organic- and aqueous-phase hydrogenation reactions was immobilized on several types of commercially available ion-exchange supports. The resulting heterogeneous catalyst was investigated in batch reactions and in an H-Cube flow reactor in the hydrogenation of phenylacetylene, diphenylacetylene, 1-hexyne, and benzylideneacetone. Under proper conditions, the catalyst was highly selective in the hydrogenation of alkynes to alkenes, and demonstrated excellent selectivity in C=C over C=O hydrogenation; furthermore, it displayed remarkable stability. Activity of 1 in hydrogenation of levulinic acid to γ-valerolactone was also assessed.

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Performance Analysis of TiO2-Modified Co/MgAl2O4 Catalyst for Dry Reforming of Methane in a Fixed Bed Reactor for Syngas (H2, CO) Production

Energies ◽

10.3390/en14113347 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3347

Author(s):

Arslan Mazhar ◽

Asif Hussain Khoja ◽

Abul Kalam Azad ◽

Faisal Mushtaq ◽

Salman Raza Naqvi ◽

...

Keyword(s):

Catalytic Activity ◽

Fixed Bed ◽

Catalytic Performance ◽

Dry Reforming ◽

Fixed Bed Reactor ◽

Dry Reforming Of Methane ◽

Catalyst Stability ◽

Feed Ratio ◽

Catalyst Loading ◽

Impregnation Method

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.

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