High-Surface-Area SBA-15 with Enhanced Mesopore Connectivity by the Addition of Poly(vinyl alcohol)

2011 ◽  
Vol 23 (8) ◽  
pp. 2062-2067 ◽  
Author(s):  
Junjiang Zhu ◽  
Kamalakannan Kailasam ◽  
Xiao Xie ◽  
Reinhard Schomaecker ◽  
Arne Thomas
2020 ◽  
Author(s):  
Komal Saraf ◽  
N Vigneshwaran

Abstract Aureobasidium pullulans isolated from the phylloplane of Peltophorum tree, produced pullulan, an extracellular polysaccharide. It was grown on three different carbon sources, sucrose, wheat bran and cotton stalk dust, for maximizing the pullulan yield. A. pullulans (67.4 gL-1) had the highest yield followed by A. pullulans MTCC 1991 (63.68 gL-1). Pullulan was characterized by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area analyzer, DSC and NMR. Electrospinning of pullulan blended with poly (vinyl alcohol) (PVA) produced bead-less nanofibres. The optimized parameters for electrospinning were 25 kV applied voltage, 0.5 mL/h flow rate, 18% polymer concentration (pullulan + PVA) and 150 mm tip-to-collector distance. The pullulan nanofibre was characterized by SEM, AFM, BET, contact angle measurement, DSC and CIE color space analyzer. A maximum surface area of 183.4 m2/g while the minimum nanofibre diameter (79 ± 19 nm by SEM) was obtained for the electrospun mat of commercial pullulan + 40% PVA. This work signifies the importance of pullulan extracted from an isolate of Peltopohorum tree for conversion to high surface area nanofibres by electrospinning process.


2020 ◽  
Author(s):  
Komal Saraf ◽  
N Vigneshwaran

Abstract Aureobasidium pullulans isolated from the phylloplane of Peltophorum tree, produced pullulan, 24 an extracellular polysaccharide. It was grown on three different carbon sources, sucrose, wheat 25 bran and cotton stalk dust, for maximizing the pullulan yield. A. pullulans (67.4 gL-1) had the 26 highest yield followed by A. pullulans MTCC 1991 (63.68 gL-1). Pullulan was characterized by 27 X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area analyzer, DSC and NMR. 28 Electrospinning of pullulan blended with poly (vinyl alcohol) (PVA) produced bead-less 29 nanofibres. The optimized parameters for electrospinning were 25 kV applied voltage, 0.5 mL/h 30 flow rate, 18% polymer concentration (pullulan + PVA) and 150 mm tip-to-collector distance. 31 The pullulan nanofibre was characterized by SEM, AFM, BET, contact angle measurement, DSC 32 and CIE color space analyzer. A maximum surface area of 183.4 m2/g while the minimum 33 nanofibre diameter (79 ± 19 nm by SEM) was obtained for the electrospun mat of commercial 34 pullulan + 40% PVA. This work signifies the importance of pullulan extracted from an isolate of 35 Peltopohorum tree for conversion to high surface area nanofibres by electrospinning process.


Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1039
Author(s):  
Paritat Muanchan ◽  
Takashi Kurose ◽  
Hiroshi Ito

Mesoscale pore one–dimensional (1D) nanostructures, or vertically aligned porous nanostructures (VAPNs), have attracted attention with their excellent hydrophobic properties, ultra−high surface area, and high friction coefficient, compared to conventional vertically aligned nanostructures (VANs). In this study, we investigate the replication of VAPNs produced by the thermal nanoimprint process using anodic aluminum oxide (AAO2) templates (100 nm diameter). Polystyrene/poly(vinyl alcohol) (PS1/PVA) blends, prepared by the advanced melt–mixing process with an ultra–high shear rate, are used to investigate the formation of porosity at the nanometer scale. The results reveal that domain size and mass ratios of PVA precursors in the PS matrix play a dominant role in the interfacial interaction behavior between PS1–PVA–AAO2, on the obtained morphologies of the imprinted nanostructures. With a PVA nanodomain precursor (PS1/PVA 90/10 wt%), the integration of PVA nanodroplets on the AAO2 wall due to the hydrogen bonding that induces the phase separation between PS1–PVA results in the formation of VAPNs after removal of the PVA segment. However, in the case of PVA microdomain precursors (PS1/PVA 70/30 wt%), the structure transformation behavior of PS1 is induced by the Rayleigh instability between PVA encapsulated around the PS1 surfaces, resulting in the PS1 nanocolumns transforming into nanopeapods composed of nanorods and nanospheres.


Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>


Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.


Author(s):  
Sisir Maity ◽  
Dheeraj Kumar Singh ◽  
Divya Bhutani ◽  
Suchitra Prasad ◽  
Umesh V. Waghmare ◽  
...  

MethodsX ◽  
2021 ◽  
pp. 101464
Author(s):  
Yichen Wu ◽  
Nan Zhang ◽  
Charles-François de Lannoy

2021 ◽  
Author(s):  
Gurwinder Singh ◽  
Rohan Bahadur ◽  
Ajanya Maria Ruban ◽  
Jefrin Marykala Davidraj ◽  
Dawei Su ◽  
...  

Nanoporous biocarbons derived from waste biomass have created significant attention owing to their great potential for energy storage and conversion and water purification. However, the fabrication technology for these materials...


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1962
Author(s):  
Mahboubeh Nabavinia ◽  
Baishali Kanjilal ◽  
Noahiro Fujinuma ◽  
Amos Mugweru ◽  
Iman Noshadi

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO2). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO2 capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO2 capture performance, with equilibrium adsorption of 2.3 mmol CO2/g at 0 °C and 1 bar for at a surface area 675.62 m2/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO2 capture and possible subsequent electrochemical conversion.


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