composite support
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Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1421
Author(s):  
Maryam Hanif ◽  
Haq Nawaz Bhatti ◽  
Muhammad Asif Hanif ◽  
Umer Rashid ◽  
Asma Hanif ◽  
...  

Disadvantages of biodiesel include consumption of edible oils for fuel production, generation of wastewater and inability to recycle catalysts during homogenously catalyzed transesterification. The aim of the current study was to utilize low-cost, inedible oil extracted from Sinapis arvensis seeds to produce biodiesel using a novel nano-composite superoxide heterogeneous catalyst. Sodium superoxide (NaO2) was synthesized by reaction of sodium nitrate with hydrogen peroxide via spray pyrolysis, followed by coating onto a composite support material prepared from silicon dioxide, potassium ferricyanide and granite. The roasted (110 °C, 20 min) and unroasted S. arvensis seeds were subjected to high vacuum fractional distillation to afford fractions (F1, F2 and F3) that correlated to molecular weight. For example, F1 was enriched in palmitic acid (76–79%), F2 was enriched in oleic acid (69%) and F3 was enriched in erucic acid (61%). These fractions, as well as pure unroasted and roasted S. arvensis seed oils, were then transesterified using NaO2/SiO2/PFC/Granite to give biodiesel a maximum yield of 98.4% and 99.2%, respectively. In contrast, yields using immobilized lipase catalyst were considerably lower (78–85%). Fuel properties such as acid value, cetane number, density, iodine value, pour point, and saponification value were within the ranges specified in the American biodiesel standard, ASTM D6751, where applicable. These results indicated that the nano-composite catalyst was excellent for production of biodiesel from unroasted and roasted S. arvensis seed oil and its fractions.


2021 ◽  
Vol 2068 (1) ◽  
pp. 012019
Author(s):  
Lan Cui ◽  
Qian Sheng ◽  
Zhenzhen Niu

Abstract This study considers that the support time is quantitatively determined by the production limit of the displacement reduction factor and the support force under the extrusion conditions of the strain-softening rock mass. Therefore, the two indicators of the downlines under the support time are the displacement reduction factor of the support force and the yield limit. Based on the solution of the fictitious pressure proposed in an existing paper, the finite difference method is adopted to investigate the variations of the support force and displacement reduction factor versus the delayed distance considering different support types, initial stresses, and post-peak behaviours. The results show that on the one hand, the delay distance is suggested within 1 R0 in most tunnel cases; on the other hand, the factors have greater impact on rock-support interactions are rock mass and in-situ stress. Relatively contrast, softening and expansion behavior was not significant enough. Furthermore, it is also very important in composite support systems to assess the proportion of loads shared with the weakest part.


2021 ◽  
Vol 11 (1) ◽  
pp. 94-98
Author(s):  
Quan Dang Long ◽  
An Nguyen Minh ◽  
Vinh Thach Phuc ◽  
Ngan Nguyen Thi Thanh ◽  
Lil Owin Khưu ◽  
...  

In this work, carbon Vulcan XC-72 (C) and carbon nanotubes (CNTs) supported ternary platinum-ruthenium-iron (PtRuFe) and platinum-ruthenium-nickel (PtRuNi) alloy nanoparticles have been synthesized by a co-reduction method. The catalyst samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The results show that ternary alloy catalysts are always better than binary alloy catalysts. In particular, PtRuNi is the best catalyst for methanol oxidation reaction. 


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 571
Author(s):  
Dang Long Quan ◽  
Phuoc Huu Le

PtRu nanoparticles decorated on carbon-based supports are of great interest for direct methanol fuel cells (DMFCs). In this study, PtRu alloy nanoparticles decorated on carbon Vulcan XC-72 (C), multi-walled carbon nanotubes (MWCNTs), and C-MWCNTs composite supports were synthesized by co-reduction method. As a result, PtRu nanoparticles obtained a small mean size (dmean = 1.8–3.8 nm) with a size distribution of 1–7 nm. We found that PtRu/C60MWCNTs40 possesses not only high methanol oxidation activity, but also excellent carbonaceous species tolerance ability, suggesting that C-MWCNTs composite support is better than either C or MWCNTs support. Furthermore, detailed investigation on PtRu/C100−xMWCNTsx (x = 10–50 wt.%) shows that the current density (Jf), catalyst tolerance ratio (Jf/Jr), and electron transfer resistance (Ret) are strongly affected by C-MWCNTs composition. The highest Jf is obtained for PtRu/C70MWCNTs30, which is considered as an optimal electrocatalyst. Meanwhile, both PtRu/C70MWCNTs30 and PtRu/C60MWCNTs40 exhibit a low Ret of 5.31–6.37 Ω·cm2. It is found that C-MWCNTs composite support is better than either C or MWCNTs support in terms of simultaneously achieving the enhanced methanol oxidation activity and good carbonaceous species tolerance.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zuo-ju Wu ◽  
Zhi-jia Wang ◽  
Jun-wei Bi ◽  
Xiao Fu ◽  
Yong Yao

The combined retaining structure has gradually received considerable attention in the slope engineering, due to its good reinforcement effects. However, most of the published research studies were focused on the seismic responses of the single-formal supporting structure only. The investigations of dynamic responses of the combined retaining structures are scarce, and the current seismic design is conducted mainly based on experiences. In this work, a series of large-scale shaking table tests were conducted to investigate the seismic responses of the combined retaining structures (i.e., prestressed anchor cables and double-row antisliding piles) and the reinforced slope under seismic excitations, including amplification effect of internal and surface acceleration of the reinforced slope, distribution and change of prestress of the anchor cable, dynamic response of soil pressure behind the antislide pile, and horizontal displacement of the reinforced slope surface. Test results show that, supported by the reinforcement of composite support system, the slope with the multilayer weak sliding surface can experience strong ground motion of 0.9 g. The load of the antisliding pile has reached 80% of its bearing capacity, and the load of the anchor cable has reached 75.0% of its bearing capacity. When the seismic intensity reaches 0.5 g, the slope surface has an obvious downward trend, which will make the corresponding soil pressure suddenly increase after the antislide pile. At the potential sliding zone, the axial force of the anchor cable will increase suddenly under the action of earthquake; after the earthquake, the initial prestress of the anchor cable will be lost, with the loss range of 17.0%∼23.0%. These test results would provide an important reference for the further study of the seismic performance of such composite support structure.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2146
Author(s):  
Gyu Sik Chae ◽  
Duck Hyun Youn ◽  
Jae Sung Lee

Nanostructured FeS dispersed onto N, S dual-doped carbon nanotube–graphene composite support (FeS/N,S:CNT–GR) was prepared by a simple synthetic method. Annealing an ethanol slurry of Fe precursor, thiourea, carbon nanotube, and graphene oxide at 973 K under N2 atmosphere and subsequent acid treatment produced FeS nanoparticles distributed onto the N, S-doped carbon nanotube–graphene support. The synthesized FeS/N,S:CNT–GR catalyst exhibited significantly enhanced electrochemical performance in the oxygen reduction reaction (ORR) compared with bare FeS, FeS/N,S:GR, and FeS/N,S:CNT with a small half-wave potential (0.827 V) in an alkaline electrolyte. The improved ORR performance, comparable to that of commercial Pt/C, could be attributed to synergy between the small FeS nanoparticles with a high activity and the N, S-doped carbon nanotube–graphene composite support providing high electrical conductivity, large surface area, and additional active sites.


2021 ◽  
Vol 179 ◽  
pp. 106503
Author(s):  
Zhichao Wang ◽  
Ke Du ◽  
Yongli Xie ◽  
Xulin Su ◽  
Yufeng Shi ◽  
...  

Author(s):  
Sandile Surprise Gwebu ◽  
Thabo Matthews ◽  
Wendy Nobanathi Maxakato

Abstract The severe corrosion of carbon supports in harsh fuel cell conditions has attracted the development of ceramic-based catalyst supports. Platinum nanoparticles supported on the carbon nanodots (CNDs)-titania (TiO2) composite were synthesized in three steps: Firstly, an inorganic support, titania (TiO2) was synthesized by a hydrolysis method. Secondly, the (CNDs-titania) nanocomposite support was prepared by sonicating pre-synthesized carbon nanodots (CNDs) and TiO2 in equal volumes of ethylene glycol/water solution. Lastly, nanosized Pt particles were deposited onto the CNDs-titania composite by a polyol method to form a platinum/(CNDs-titania nanocatalyst. X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and X-ray difractommetry (XRD) were used to study surface morphology of the synthesized materials. Platinum loading onto the (CNDs-titania) composite support was quantified by ICP-OES. The electrooxidation of alcohol fuels was investigated in acidic electrolytes using chronoamperometric and voltammetric techniques. It was noted that the addition of TiO2 increases electroactivity of the nanocatalysts. The platinum/(CNDs-titania) nanocatalyst exhibited superior electroactivity during methanol and ethanol electrooxidation compared to the platinum/CNDs and Pt/C benchmark standards. Chronoamperometry (CA) curves showed that the platinum/(CNDs-titania) nanocatalyst exhibited outstanding anti-poisoning properties relative to the platinum/CNDs and commercial Pt/C nanocatalysts.


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