scholarly journals Effect of the oxygen coordination environment of Ca–Mn oxides on the catalytic performance of Pd supported catalysts for aerobic oxidation of 5-hydroxymethyl-2-furfural

2019 ◽  
Vol 9 (23) ◽  
pp. 6659-6668 ◽  
Author(s):  
Jie Yang ◽  
Haochen Yu ◽  
Yanbing Wang ◽  
Fuyuan Qi ◽  
Haodong Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Charge Transfer ◽  
Active Sites ◽  
Supported Catalysts ◽  
Aerobic Oxidation ◽  
Oxygen Adsorption ◽  
Catalytic Performance ◽  
Coordination Environment ◽  
Oxygen Coordination ◽  
Mn Oxides

Pd/CaMn2O4 provides ideal active sites for oxygen adsorption and desorption, resulting in the promoted charge transfer ability and catalytic activity.

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

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
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.

scholarly journals Engineering Active Sites in Reduced Graphene Oxide: Tuning the Catalytic Activity for Aerobic Oxidation

2019 ◽  
Vol 7 (19) ◽  
pp. 15948-15956 ◽  
Author(s):  
Juan C. Espinosa ◽  
Mercedes Álvaro ◽  
Amarajothi Dhakshinamoorthy ◽  
Sergio Navalón ◽  
Hermenegildo García
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Reduced Graphene Oxide ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Reduced Graphene

Catalytic Performance of SO2 by Colloidal Gold Supported on Nano γ-Fe2O3

2010 ◽  
Vol 178 ◽  
pp. 65-70 ◽  
Author(s):  
Sheng Rui Xu ◽  
Qin Shuai ◽  
Jin Hua Cheng ◽  
Xiao Ge Wang
Keyword(s):  
Gas Chromatography ◽  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Metal Oxides ◽  
Water Vapour ◽  
Colloidal Gold ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Sulfate Species

A new catalyst of gold supported on nanometal oxide for oxidation of SO2 was developed. Deposition-precipitation method was used to prepare gold-based catalysts. The catalytic activity of the catalysts was evaluated by determining the concentration of SO2 with gas chromatography under reaction temperature from 100 to 700°C. The results showed that there was an enhancement of catalytic activity when gold nanoparticles were dispersed on the surface of nano-metal oxides, furthermore, γ-Fe2O3 showed the highest activity as the support of the colloidal gold supported catalysts among the nanometal oxides including γ-Fe2O3, Fe2O3, ZnO, and Al2O3. It was also found that water vapour in the reaction enhanced the catalytic activity of Au/γ-Fe2O3. The Au/γ-Fe2O3 was characterized by XRD and FTIR methods, which indicated that the gold nanoparticles were dispersed on the γ-Fe2O3 support and sulfate species were formed on the surface of catalysts.

scholarly journals Controlling catalytic activity and selectivity for partial hydrogenation by tuning the environment around active sites in iridium complexes bonded to supports

2019 ◽  
Vol 10 (9) ◽  
pp. 2623-2632 ◽  
Author(s):  
Melike Babucci ◽  
Chia-Yu Fang ◽  
Jorge E. Perez-Aguilar ◽  
Adam S. Hoffman ◽  
Alexey Boubnov ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Catalytic Activity ◽  
Active Sites ◽  
Catalytic Performance ◽  
Partial Hydrogenation ◽  
Iridium Complexes

Enveloping atomically dispersed supported iridium with the choice of ionic liquid molecular sheaths and supports controls the catalytic performance.

Carbon Dioxide Hydrogenation to Methanol over Cu/ZnO-SBA-15 Catalyst: Effect of Metal Loading

2017 ◽  
Vol 380 ◽  
pp. 151-160 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Maizatul Shima Shaharun ◽  
Duvvria Subbarao ◽  
Ahmed Elbagir
Keyword(s):  
Catalytic Activity ◽  
Carbon Source ◽  
Active Sites ◽  
Low Cost ◽  
Fixed Bed ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Supported Metal Catalysts ◽  
Metal Loading

Utilization of CO2 as a carbon source to produce valuable chemicals is one of the important ways to reduce the global warming caused by increasing CO2 in the atmosphere. Supported metal catalysts are crucial to produce clean and renewable fuels and chemicals from the stable CO2 molecules. The catalytic conversion of CO2 into methanol is recently under increased scrutiny as an opportunity to be used as a low-cost carbon source. Therefore, a series of the bimetallic Cu/ZnO-based catalyst supported by SBA-15 were synthesized via an impregnation technique with different total metal loading and tested in the catalytic hydrogenation of CO2 to methanol. The morphological and textural properties of the synthesized catalysts were determined by transmission electron microscopy (TEM), temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO), and N2-adsorption. The CO2 hydrogenation reaction was performed in a microactivity fixed-bed system at 250oC, 2.25 MPa, and H2/CO2 ratio of 3. Experimental results showed that the catalytic structure and performance were strongly affected by the loading of the active site. Where, the catalytic activity, the methanol selectivity as well as the space-time yield increased with increasing the metal loading until it reaches the maximum values at a metal loading of 15 wt% while further addition of metal inhibits the catalytic performance. The higher catalytic activity of 14% and methanol selectivity of 92% was obtained over a Cu/ZnO-SBA-15 catalyst with a total bimetallic loading of 15 wt%. The excellent performance of 15 wt% Cu/ZnO-SBA-15 catalyst is attributed to the presence of well dispersed active sites with small particle size, higher Cu surface area, and lower catalytic reducibility.

scholarly journals Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽  
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.

scholarly journals Properties and catalytic performance of sulphate-vanadia impregnated fumed silica as oxidative catalyst

2015 ◽  
Vol 11 (2) ◽  
Author(s):  
Nor Masdiana Zulkeple ◽  
Norhasyimah Mohd Kamal ◽  
Jamilah Mohd Ekhsan ◽  
Salasiah Che Me ◽  
Swee Ean Lim ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Charge Transfer ◽  
Surface Area ◽  
Sulphuric Acid ◽  
Fumed Silica ◽  
Catalytic Performance ◽  
Support Surface ◽  
High Catalytic Activity ◽  
Impregnation Method

A series of sulphate-vanadia impregnated fumed silica oxidative catalysts were synthesized via impregnation method. The samples were prepared by impregnation of 1 wt% of vanadium and 0.2 M of sulphuric acid onto fumed silica as support. Surface area of the silica supported samples were similar of 118 m2/g. UV-Vis DRS results showed existence of o supported V species and the charge transfer bands associated with O2- to V5+ in tetrahedral environments. Catalytic performance were evaluated via epoxidation of 1-octene to 1,2-epoxyoctane using hydrogen peroxide as an oxidant. It had been demonstrated that sulphate-vanadia impregnated fumed silica had high catalytic activity of 626 ± 0.2 mmol epoxide was produced after 24 h reaction. This may indicate that more oxidative sites were generated after the impregnation of V and sulphate onto the SiO2 matrixes.

High-heat treatment enhanced catalytic activity of CuO/CeO2 catalysts with low CuO content for CO oxidation

2020 ◽  
Vol 10 (15) ◽  
pp. 5256-5266 ◽  
Author(s):  
Jihang Yu ◽  
Qiangsheng Guo ◽  
Xiuzhen Xiao ◽  
Haifang Mao ◽  
Dongsen Mao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Active Sites ◽  
High Heat ◽  
Catalytic Performance

CuO/CeO2 catalysts with low CuO content and calcined at 800 °C exhibited better catalytic performance than those calcined at 500 °C. The coordinatively unsaturated copper atoms were proved to be the main active sites in the CuO/CeO2 catalysts.

Cobalt, iron co-incorporated Ni(OH)2 multiphase for superior multifunctional electrocatalytic oxidation

2021 ◽  
Author(s):  
Pin Hao ◽  
Ruirui Xu ◽  
Qian Wang ◽  
Zhenhuan Zhao ◽  
Houguang Wen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Charge Transfer ◽  
Active Sites ◽  
Electrocatalytic Oxidation ◽  
Cobalt Iron

Cobalt, iron co-incorporated Ni(OH)2 multiphase displays superior catalytic activity and stability for multifunctional electrocatalytic oxidation, ascribing to the multiphase synergy, the enhanced charge transfer and the well-exposed active sites.

Effect of Different Silicate Supports on the Catalytic Performance of MoVTeO Mixed Oxides in Partial Oxidation of Isobutane

2014 ◽  
Vol 12 (1) ◽  
pp. 623-628
Author(s):  
Jing Hu ◽  
Zhifang Li ◽  
Xiaoyuan Yang ◽  
Wenli Ding ◽  
Jingqi Guan
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Partial Oxidation ◽  
Mixed Oxides ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Mcm 41

Abstract A series of 5% MoV0.3Te0.25 supported on different silicates (i.e. SiO2, HMS, MCM-41, and MCM-48) have been prepared, characterized, and tested as catalysts in the partial oxidation of isobutane to methacrolein. Characterization results showed that the supports almost kept intact structures after supporting 5 wt.% MoV0.3Te0.25 and the supported catalysts had large specific surface areas. Catalytic tests showed that the specific surface area played a key role in the catalytic activity for the supported catalysts.

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