scholarly journals The Role of Strontium in CeNiO3 Nano-Crystalline Perovskites for Greenhouse Gas Mitigation to Produce Syngas

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 356
Author(s):  
Naushad Ahmad ◽  
Rizwan Wahab ◽  
Salim Manoharadas ◽  
Basel F. Alrayes ◽  
Munawwer Alam ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Catalytic Performance ◽  
Catalyst Stability ◽  
Methane Reforming ◽  
Metal Support Interaction ◽  
Production Of Hydrogen

The transition metal-based catalysts for the elimination of greenhouse gases via methane reforming using carbon dioxide are directly or indirectly associated with their distinguishing characteristics such as well-dispersed metal nanoparticles, a higher number of reducible species, suitable metal–support interaction, and high specific surface area. This work presents the insight into catalytic performance as well as catalyst stability of CexSr1−xNiO3 (x = 0.6–1) nanocrystalline perovskites for the production of hydrogen via methane reforming using carbon dioxide. Strontium incorporation enhances specific surface area, the number of reducible species, and nickel dispersion. The catalytic performance results show that CeNiO3 demonstrated higher initial CH4 (54.3%) and CO2 (64.8%) conversions, which dropped down to 13.1 and 19.2% (CH4 conversions) and 26.3 and 32.5% (CO2 conversions) for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3, respectively. This drop in catalytic conversions post strontium addition is concomitant with strontium carbonate covering nickel active sites. Moreover, from the durability results, it is obvious that CeNiO3 exhibited deactivation, whereas no deactivation was observed for Ce0.8Sr0.2NiO3 and Ce0.6Sr0.4NiO3. Carbon deposition during the reaction is mainly responsible for catalyst deactivation, and this is further established by characterizing spent catalysts.

Silver nanocrystal-decorated polyoxometalate single-walled nanotubes as nanoreactors for desulfurization catalysis at room temperature

Nanoscale ◽  
2017 ◽  
Vol 9 (35) ◽  
pp. 13334-13340 ◽  
Author(s):  
Hao Zhang ◽  
Xiaobin Xu ◽  
Haifeng Lin ◽  
Muhammad Aizaz Ud Din ◽  
Haiqing Wang ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Room Temperature ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Single Walled Nanotubes

Ultrathin nanocrystals generally provide a remarkable catalytic performance due to their high specific surface area and exposure of certain active sites.

Preparation of Fe/N co-doped hierarchical porous carbon nanosheets derived from chitosan nanofibers for high-performance supercapacitors

2021 ◽  
pp. 1-16
Author(s):  
Yaqi Yang ◽  
Ziqiang Shao ◽  
Feijun Wang
Keyword(s):  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Porous Carbon ◽  
Active Sites ◽  
Transport Pathway ◽  
Carbon Nanosheets ◽  
Hierarchical Porous

Abstract Due to the low specific capacitance and small specific surface area of conventional carbon materials used as electrode materials for double-layer capacitors, the search for more ideal materials and ingenious preparation methods remains a major challenge. In this study, fractional porous carbon nanosheets were prepared by co-doping Fe and N with chitosan as nitrogen source. The advantage of this method is that the carbon nanosheets can have a large number of pore structures and produce a large specific surface area. The presence of Fe catalyzes the graphitization of carbon in the carbon layer during carbonization process, and further increases the specific surface area of the electrode material. This structure provides an efficient ion and electron transport pathway, which enables more active sites to participate in the REDOX reaction, thus significantly enhancing the electrochemical performance of SCs. The specific surface area of CS-800 is up to 1587 m2 g−1. When the current density is 0.5 A g−1, the specific capacitance of CS-800 reaches 308.84 F g−1, and remains 84.61 % of the initial value after 10,000 cycles. The Coulomb efficiency of CS-800 is almost 100 % after a long cycle, which indicates that CS-800 has more ideal double-layer capacitance and pseudo capacitance.

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

Titania nanotubes coated with graphene as a promising catalyst for the oxygen reduction reaction

2020 ◽  
Vol 44 (18) ◽  
pp. 7417-7423
Author(s):  
Jiannan Cai ◽  
Xiaofeng Zhang ◽  
Yi Zhang ◽  
Mingxing Yang ◽  
Baohua Huang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Specific Surface ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Reduction Reaction ◽  
Titania Nanotubes ◽  
Electron Conductivity ◽  
Electrocatalytic Properties

The enhanced electrocatalytic properties of rGO/TiO2NTs for the ORR are a result of increased specific surface area, number of active sites and accelerated electron conductivity.

Preparation, characterization and catalytic properties of yttrium-zirconium-pillared montmorillonite and their application in supported Ce catalysts

Clay Minerals ◽  
2015 ◽  
Vol 50 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Bo Xue ◽  
Hongmei Guo ◽  
Lujie Liu ◽  
Min Chen
Keyword(s):  
Catalytic Activity ◽  
Ethyl Acetate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Industrial Applications ◽  
High Catalytic Activity ◽  
Total Oxidation ◽  
Pillared Montmorillonite

AbstractA new yttrium-zirconium-pillared montmorillonite (Y-Zr-MMT), was synthesized, characterized and used as a Ce catalyst support. The Y-Zr-MMT is a good support for dispersing cerium active sites and it is responsible for the high activity in the total oxidation of acetone, toluene and ethyl acetate. The Y-Zr-MMT shows greater advantages than the conventional alumina/cordierite honeycomb supports such as large specific surface area, lower cost and easier preparation. Catalytic tests demonstrated that Ce/Y-Zr-MMT (Ce loading 8.0%) was the most active, with the total oxidation of acetone, toluene and ethyl acetate being achieved at 220, 300 and 220°C, respectively. The catalyst displayed better activity for the oxidation of acetone and ethyl acetate than a conventional, supported Pd-catalyst under similar conditions. The special structure of the yttrium-doped zirconium-pillared montmorillonite can strengthen the interaction between the CeO2 and Zr-MMT support and improve the dispersion of the Ce particles, which enhances the catalytic activity for the oxidation of VOCs. The new catalyst, 8.0%Ce/Y-Zr-MMT, could be promising for industrial applications due to its high catalytic activity and low cost. The support and the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET specific surface area measurements.

scholarly journals Carbon Dioxide Absorption and Release Properties of Pyrolysis Products of Dolomite Calcined in Vacuum Atmosphere

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Fei Wang ◽  
Toshihiro Kuzuya ◽  
Shinji Hirai ◽  
Jihua Li ◽  
Te Li
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Micropore Volume ◽  
Carbon Dioxide Absorption ◽  
Pyrolysis Products ◽  
Vacuum Atmosphere

The decomposition of dolomite into CaO and MgO was performed at 1073 K in vacuum and at 1273 K in an Ar atmosphere. The dolomite calcined in vacuum was found to have a higher specific surface area and a higher micropore volume when compared to the dolomite calcined in the Ar atmosphere. These pyrolysis products of dolomite were reacted with CO2at 673 K for 21.6 ks. On the absorption of CO2, the formation of CaCO3was observed. The degree of absorption of the dolomite calcined in vacuum was determined to be above 50%, which was higher than the degree of absorption of the dolomite calcined in the Ar atmosphere. The CO2absorption and release procedures were repeated three times for the dolomite calcined in vacuum. The specific surface area and micropore volume of calcined dolomite decreased with successive repetitions of the CO2absorption and release cycles leading to a decrease in the degree of absorption of CO2.

scholarly journals Removal efficiency and mechanism of bio-treated coking wastewater by catalytic ozonation using MnO2 modified with anionic precursors

2020 ◽  
Vol 26 (5) ◽  
pp. 200394-0
Author(s):  
Jie Zhang ◽  
Ben Dong ◽  
Ding Ding ◽  
Shilong He ◽  
Sijie Ge
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Catalytic Performance ◽  
Catalytic Ozonation ◽  
Relative Content ◽  
Precipitation Method ◽  
Coking Wastewater ◽  
Physiochemical Properties ◽  
Removal Efficiencies

In this paper, MnO<sub>2</sub> catalyst were firstly prepared and modified by four kinds of anionic precursors (i.e., NO<sub>3</sub><sup>-</sup>, AC<sup>-</sup>, SO<sub>4</sub><sup>2-</sup> and Cl<sup>-</sup>) through redox precipitation method. After that, bio-treated coking wastewater (BTCW) was prepared and employed as targeted pollutants to investigate the catalytic ozonation performance of prepared-MnO<sub>2</sub> catalyst was investigated and characterized by the removal efficiencies and mechanism of the prepared bio-treated coking wastewater (BTCW), which was employed as the targeted pollutants. Specifically, the effects of specific surface area, crystal structure, valence state of Mn element and lattice oxygen content on catalytic activity of MnO<sub>2</sub> materials were characterized by BET, XRD and XPS, respectively. Results showed that COD of BTCW could be removed 47.39% under MnO<sub>2</sub>-NO<sub>3</sub><sup>-</sup> catalyst with 2 h reaction time, which was much higher than that of MnO<sub>2</sub>-AC<sup>-</sup> (3.94%), MnO<sub>2</sub>-SO<sub>4</sub><sup>2-</sup> (12.42%), MnO<sub>2</sub>-Cl<sup>-</sup> (12.94%) and pure O<sub>3</sub> without catalyst (21.51%), respectively. So, MnO<sub>2</sub>-NO<sub>3</sub><sup>-</sup> presented the highest catalytic performance among these catalysts. The reason may be attributed to a series of better physiochemical properties including the smaller average grain, the larger specific surface area and active groups, more crystal defect and oxygen vacancy, higher relative content of Mn<sup>3+</sup> and adsorbed oxygen (O<sub>ads</sub>) than that of another three catalysts.

scholarly journals Application of CoMn/CoFe layered double hydroxide based on metal-organic frameworks template to activate peroxymonosulfate for 2, 4-dichlorophenol degradation

2021 ◽  
Author(s):  
Chenyu Liu ◽  
Haitong Wei ◽  
Yanhui Gao ◽  
Ning Wang ◽  
Xiaoying Yuan ◽  
...  
Keyword(s):  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Metal Organic Frameworks ◽  
High Specific Surface Area ◽  
State Transformation ◽  
Alkaline Conditions ◽  
Metal Organic

Abstract Metal-Organic Frameworks (MOFs) have unique properties and stable structure, which have been widely used as templates/precursors to prepare well-developed pore structure and high specific surface area materials. In this article, an innovative and facile method of crystal reorganization was designed by using MOFs as sacrificial templates to prepare LDH nano-layer sheet structure through a pseudomorphic conversion process under alkaline conditions. The obtained CoMn-LDH and CoFe-LDH catalysts broke the ligand of MOFs and reorganized the structure on the basis of retaining a high specific surface area and a large number of pores, which have higher specific surface area and well-developed pore structure than LDH catalysts prepared by traditional methods, and thus provide more active sites to activate PMS. Due to the unique framework structure of MOFs, the MOF derived CoMn-LDH and CoFe-LDH catalysts could provide more active sites to activate PMS, and achieve a 2, 4-dichlorophenol (2, 4-DCP) degradation of 99.3% and 99.2% within 20 min, respectively. Besides, the two LDH catalysts displayed excellent degradation performance for bisphenol A (BPA), ciprofloxacin (CIP) and 2, 4-dichlorophenoxyacetic acid (2, 4-D). XPS indicated that the valence state transformation of metal elements participated in PMS activation. EPR manifested sulfate radical () and singlet oxygen (1O2) were the main species for degrading pollutants. In addition, after the three-cycle experiment, the CoMn-LDH and CoFe-LDH catalysts also showed long-term stability with a slight activity decrease in the third cycle. The phytotoxicity assessment determined by the germination of mung beans proved that PMS activation by MOFs-derived LDH catalyst can basically eliminate the phytotoxicity of 2, 4-D solution. This research not only developed high-activity LDH catalysts for PMS activation, but also expanded the environmental applications of MOFs derivants.

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