scholarly journals Electrospun Composites Made of Reduced Graphene Oxide and Polyacrylonitrile-Based Activated Carbon Nanofibers (rGO/ACNF) for Enhanced CO2 Adsorption

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2117
Author(s):  
Faten Ermala Che Othman ◽  
Norhaniza Yusof ◽  
Javier González-Benito ◽  
Xiaolei Fan ◽  
Ahmad Fauzi Ismail
Keyword(s):  
Graphene Oxide ◽  
Activated Carbon ◽  
Reduced Graphene Oxide ◽  
Carbon Nanofibers ◽  
Co2 Adsorption ◽  
Morphological Properties ◽  
Co2 Uptake ◽  
Order Model ◽  
Activated Carbon Nanofibers ◽  
Reduced Graphene

In this work, we report the preparation of polyacrylonitrile (PAN)-based activated carbon nanofibers composited with different concentrations of reduced graphene oxide (rGO/ACNF) (1%, 5%, and 10% relative to PAN weight) by a simple electrospinning method. The electrospun nanofibers (NFs) were carbonized and physically activated to obtain activated carbon nanofibers (ACNFs). Texture, surface and elemental properties of the pristine ACNFs and composites were characterized using various techniques. In comparison to pristine ACNF, the incorporation of rGO led to changes in surface and textural characteristics such as specific surface area (SBET), total pore volume (Vtotal), and micropore volume (Vmicro) of 373 m2/g, 0.22 cm3/g, and 0.15 cm3/g, respectively, which is much higher than the pristine ACNFs (e.g., SBET = 139 m2/g). The structural and morphological properties of the pristine ACNFs and their composites were studied by Raman spectroscopy and X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) respectively. Carbon dioxide (CO2) adsorption on the pristine ACNFs and rGO/ACNF composites was evaluated at different pressures (5, 10, and 15 bars) based on static volumetric adsorption. At 15 bar, the composite with 10% of rGO (rGO/ACNF0.1) that had the highest SBET, Vtotal, and Vmicro, as confirmed with BET model, exhibited the highest CO2 uptake of 58 mmol/g. These results point out that both surface and texture have a strong influence on the performance of CO2 adsorption. Interestingly, at p < 10 bar, the adsorption process of CO2 was found to be quite well fitted by pseudo-second order model (i.e., the chemisorption), whilst at 15 bar, physisorption prevailed, which was explained by the pseudo-first order model.

scholarly journals Novel Activated Carbon Nanofibers Composited with Cost-Effective Graphene-Based Materials for Enhanced Adsorption Performance toward Methane

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2064
Author(s):  
Faten Ermala Che Othman ◽  
Norhaniza Yusof ◽  
Noorfidza Yub Harun ◽  
Muhammad Roil Bilad ◽  
Juhana Jaafar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Activated Carbon ◽  
Specific Surface ◽  
Pore Size ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Specific Surface Area ◽  
Activated Carbon Nanofibers ◽  
Reduced Graphene

Various types of activated carbon nanofibers’ (ACNFs) composites have been extensively studied and reported recently due to their extraordinary properties and applications. This study reports the fabrication and assessments of ACNFs incorporated with graphene-based materials, known as gACNFs, via simple electrospinning and subsequent physical activation process. TGA analysis proved graphene-derived rice husk ashes (GRHA)/ACNFs possess twice the carbon yield and thermally stable properties compared to other samples. Raman spectra, XRD, and FTIR analyses explained the chemical structures in all resultant gACNFs samples. The SEM and EDX results revealed the average fiber diameters of the gACNFs, ranging from 250 to 400 nm, and the successful incorporation of both GRHA and reduced graphene oxide (rGO) into the ACNFs’ structures. The results revealed that ACNFs incorporated with GRHA possesses the highest specific surface area (SSA), of 384 m2/g, with high micropore volume, of 0.1580 cm3/g, which is up to 88% of the total pore volume. The GRHA/ACNF was found to be a better adsorbent for CH4 compared to pristine ACNFs and reduced graphene oxide (rGO/ACNF) as it showed sorption up to 66.40 mmol/g at 25 °C and 12 bar. The sorption capacity of the GRHA/ACNF was impressively higher than earlier reported studies on ACNFs and ACNF composites. Interestingly, the CH4 adsorption of all ACNF samples obeyed the pseudo-second-order kinetic model at low pressure (4 bar), indicating the chemisorption behaviors. However, it obeyed the pseudo-first order at higher pressures (8 and 12 bar), indicating the physisorption behaviors. These results correspond to the textural properties that describe that the high adsorption capacity of CH4 at high pressure is mainly dependent upon the specific surface area (SSA), pore size distribution, and the suitable range of pore size.

Activated carbon nanofibers incorporated metal oxides for CO2 adsorption: Effects of different type of metal oxides

2021 ◽  
Vol 45 ◽  
pp. 101434
Author(s):  
Faten Ermala Che Othman ◽  
Norhaniza Yusof ◽  
Sadaki Samitsu ◽  
Norfadhilatuladha Abdullah ◽  
Muhammad Faris Hamid ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Metal Oxides ◽  
Carbon Nanofibers ◽  
Co2 Adsorption ◽  
Activated Carbon Nanofibers ◽  
Adsorption Effects

scholarly journals Tailoring the Electrochemical and Morphological Properties of Electropolymerized and Dropcast Reduced Graphene Oxide-Poly(3,4-ethylene dioxythiophene):polystyrenesulfonate Transducers for Ion-Selective Sensors

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 11
Author(s):  
Ihda Uswatun Shalihah Shohibuddin ◽  
Wan Wardatul Amani Wan Salim
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Continuous Measurement ◽  
Morphological Characteristics ◽  
Potential Method ◽  
Morphological Properties ◽  
Carbon Electrodes ◽  
Peak Potential ◽  
Electron Transfer Rate ◽  
Reduced Graphene

Fabrication of ion-selective sensors for continuous measurement in fluids depends on understanding the electrochemical and morphological properties of transducers. Electropolymerized nanomaterials essentially offer stable transducers that can reduce measurement drifts. This study aims to elucidate the electrochemical and morphological characteristics of electropolymerized reduced graphene oxide stabilized in polystyrenesulfonate and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate composites on screen-printed carbon electrodes (rGO:PSS-PEDOT:PSS/SPCEs) using scanning electron microscopy (SEM) and cyclic voltammetry (CV) in 0.1 M potassium ferricyanide (K3Fe(CN)6) solution. We fabricated the rGO:PSS-PEDOT:PSS/SPCEs by two different techniques: electropolymerization deposition (EPD) and drop-casting (DC). Results revealed smaller peak-to-peak potential separation (∆Ep) of 360 mV for EPD rGO:PSS-PEDOT:PSS/SPCEs, compared to 510 mV for the DC rGO:PSS-PEDOT:PSS/SPCEs. A smaller ∆Ep indicates higher reversibility and faster electron-transfer rate at the electrode-analyte interface. SEM results showed EPD rGO:PSS-PEDOT:PSS/SPCEs have the roughest surface among electrodes; homogeneous globular structures with diameter range of 1.4–5.3 µm covered the electrode surface. In terms of electrode integrity in fluids, cracks can be seen on the surface of DC PEDOT:PSS/SPCEs after undergoing CV in 0.1 M K3Fe(CN)6, whereas rGO:PSS-PEDOT:PSS/SPCEs for both deposition methods maintained their integrity. Globular structures of rGO:PSS-PEDOT:PSS using EPD methods remained after undergoing CV. The results suggest that EPD serves as a potential method to fabricate a stable transducer for ion-selective sensing. This study aims to elucidate performance of nanocomposites via EPD methods, to develop stable ion-selective sensors for physiological and environmental applications.

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