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2D atomic crystals such as single layer graphene (SLG) and hexagonal boron nitride (hBN) have been shown to be 'unexpectedly permeable' to hydrogen ions under ambient conditions with the proton conductivity rising exponentially with temperature. Here, the first successful addition of SLG made by a chemical vapor deposition (CVD) method is shown to an operational direct methanol fuel cell significantly enhancing the performance of the cell once the temperature is raised above 60 °C, the temperature at which the proton conductivity of SLG is higher than the Nafion membrane on which it is mounted. Above this temperature, the resistance to proton transport of the system is not affected by the graphene but the barrier properties of graphene inhibit methanol crossover. The performance of the fuel cell is shown to increase linearly with coverage of SLG above this temperature. Results show that the maximum power density is increased at 70 °C by 45% in comparison to the standard membrane electrode assembly without graphene. In addition, a membrane with CVD hBN shows enhanced performance across the entire temperature range due to better proton conductivity at lower temperatures. [ABSTRACT FROM AUTHOR]

This paper deals with the kinetic and isotherm studies of manganese ion removal by zeolite X and its hierarchically porous composites as ion-exchange materials. A hydrothermal treatment was applied to grow a layer of zeolite X over diatomite and carbon surfaces. The hierarchically porous composites used for Mn 2+ ion removal showed higher ion-exchange capacity when compared to pure zeolite X under same conditions. A thermodynamic study of the rate of ion-exchange revealed that the intra-particle diffusion rate constant of zeolite X/carbon and zeolite X/diatomite was higher than that of pure zeolite X indicating that the intra-particle diffusion was enhanced when zeolite was prepared in form of hierarchically porous composites. The study showed that the thickness of boundary film of zeolite X/carbon and zeolite X/diatomite was less than that of pure zeolite X indicating ion diffusion resistance to the active sites was reduced when the composites were utilised. The experimental data showed good agreement with Freundlich model. The calculated thermodynamic parameters such as ΔG°, ΔH° and ΔS° indicated the ion-exchange process of Mn 2+ ion by zeolite X and its composites was spontaneous, endothermic and the randomness increased at the liquid/solid interface under the conditions studied. The results of kinetic study showed that the ion-exchange of Mn 2+ ion by zeolite X and its composites followed a pseudo second order kinetic model indicating Mn 2+ ion removal is a chemical reaction related to valence forces. The encapsulation of Mn 2+ ion was successfully achieved by vitrification and geopolymerization processes demonstrating the efficacy of both processes for environmental management. [ABSTRACT FROM AUTHOR]

Highly microporous and mesoporous activated carbons were produced from waste tea for application as supercapacitor electrodes, utilising a chemical activation method involving treatment with either K 2 CO 3 or H 3 PO 4 . The area, pore structure characteristics and surface functionality of the activated carbons were evaluated to investigate the influence on electrochemical performance. The performance of the activated carbons as supercapacitor electrodes was tested by cyclic voltammetry (CV), impedance spectroscopy (EIS) and galvanostatic charge–discharge (GCD) measurements, in an aqueous electrolyte. The results showed that the pore structure and type of the activated carbon have significant impact on the supercapacitor performance. Both waste tea-based activated carbon electrodes showed good cyclic stability. However, despite its lower specific surface area the highly microporous activated carbon produced with K 2 CO 3 , exhibited much better capacitive performance than that of the mesoporous activated carbon produced with H 3 PO 4 . [ABSTRACT FROM AUTHOR]

Abstract: Polyvinylalcohol–mordenite (PVA–MOR) mixed matrix membranes were synthesized for direct methanol fuel cell (DMFC) use. For the structural and the morphological characterization, Scanning Electron Microscopy and Thermal Gravimetric Analysis methods were used. Zeolite distribution within the polymer matrix was found to be homogeneous. An impedance spectroscope was used to measure the proton conductivity. In order to obtain information about methanol permeation characteristics, swelling tests and a series of pervaporation experiments were carried out. 60–40wt% PVA–MOR membranes were found to give the optimum transport properties. Proton conductivity of these membranes was found to be slightly lower than that of Nafion117™ whereas their methanol permeability was at least two orders of magnitude lower than Nafion117™. DMFC performance of the PVA–MOR membranes was also measured. The inferior DMFC performance of PVA–MOR membranes was linked to drying in the fuel cell medium and the consequent proton conductivity loss. Their performance was improved by adding a dilute solution of sulfuric acid into the feed methanol solution. Future studies on the improvement of the proton conductivity of PVA–MOR membranes, especially via sulfonation of the polymer matrix, can overcome the low-performance problem associated with insufficient proton conductivity. [Copyright &y& Elsevier]

The modification of the water/organic interface with size-selective membranes is presented as a means to elucidate the mechanism of facilitated ion transfer processes. In particular, an interfacial or organic phase complexation reaction is observed for the transfer of Cu2+ ions facilitated by dibenzo-18-crown-6, whereas the complexation process for the 1,4,7,10-tetrathiacyclododecane facilitated transfer of the same ion is suggested to occur within the aqueous phase. The contrasting transfer mechanism is discussed in terms of the solution phase behaviour of the thio-ether ligand. [Copyright &y& Elsevier]

The use of kaolin as a silica source in the synthesis of zeolites has been achieved using a novel synthetic approach. The technique reported allows the use of impure kaolin as a starting material to produce pure ZSM-5 zeolite. This is important as it is extremely difficult and time consuming to remove all impurities from natural kaolin. This is also the first report of the direct synthesis of a high silica zeolite from kaolin without the use of an external silica source. [ABSTRACT FROM AUTHOR]

The use of kaolin as a silica source in the synthesis of zeolites has been achieved using a novel synthetic approach. The technique reported allows the use of impure kaolin as a starting material to produce pure ZSM-5 zeolite. This is important as it is extremely difficult and time consuming to remove all impurities from natural kaolin. This is also the first report of the direct synthesis of a high silica zeolite from kaolin without the use of an external silica source. [ABSTRACT FROM AUTHOR]

Background: Biogeochemical processing of metals including the fabrication of novel nanomaterials from metal contaminated waste streams by microbial cells is an area of intense interest in the environmental sciences. Results: Here we focus on the fate of Ce during the microbial reduction of a suite of Ce-bearing ferrihydrites with between 0.2 and 4.2 mol% Ce. Cerium K-edge X-ray absorption near edge structure (XANES) analyses showed that trivalent and tetravalent cerium co-existed, with a higher proportion of tetravalent cerium observed with increasing Ce-bearing of the ferrihydrite. The subsurface metal-reducing bacterium Geobacter sulfurreducens was used to bioreduce Ce-bearing ferrihydrite, and with 0.2 mol% and 0.5 mol% Ce, an Fe(II)-bearing mineral, magnetite (Fe(II)(III)2O4), formed alongside a small amount of goethite (FeOOH). At higher Ce-doping (1.4 mol% and 4.2 mol%) Fe(III) bioreduction was inhibited and goethite dominated the final products. During microbial Fe(III) reduction Ce was not released to solution, suggesting Ce remained associated with the Fe minerals during redox cycling, even at high Ce loadings. In addition, Fe L2,3 X-ray magnetic circular dichroism (XMCD) analyses suggested that Ce partially incorporated into the Fe(III) crystallographic sites in the magnetite. The use of Ce-bearing biomagnetite prepared in this study was tested for hydrogen fuel cell catalyst applications. Platinum/carbon black electrodes were fabricated, containing 10% biomagnetite with 0.2 mol% Ce in the catalyst. The addition of bioreduced Ce-magnetite improved the electrode durability when compared to a normal Pt/CB catalyst. Conclusion: Different concentrations of Ce can inhibit the bioreduction of Fe(III) minerals, resulting in the formation of different bioreduction products. Bioprocessing of Fe-minerals to form Ce-containing magnetite (potentially from waste sources) offers a sustainable route to the production of fuel cell catalysts with improved performance. [ABSTRACT FROM AUTHOR]

A direct methanol fuel cell (DMFC) is one prominent alternative energy technology. However, there are many problems that prevent the commercialization of DMFC, such as methanol crossover, low power density, and degradation of the membrane. To resolve these issues, functionalized graphene oxide (GO) and calcium hydroxy phosphate (CHP) were incorporated into the Nafion membrane to make a composite membrane. The content of the CHP was varied to determine and further investigation involved spraying the same amount of CHP onto the Nafion membrane to compare with the composite membrane. The fillers were characterized using Fourier-transform infrared spectroscopy and X-ray Powder Diffraction. The ex-situ tests investigated water uptake, solubility, and chemical degradation, while the in-situ tests investigated electrochemical impedance (EIS), methanol permeability, fuel cell performance, and durability. Adding both 1 wt% of CHP and 0.05 wt% functionalized GO into the Nafion membrane, resulting in a 1.86-fold higher durability than that of recast Nafion. In addition, the maximum power density of the composite membrane was 1.34-fold higher (75.41 mW/cm2) than that of the recast Nafion (56.11 mW/cm2) at 1 M methanol and 70 °C. At 2 M methanol and 70 °C, the maximum power density of the composite membrane increased to 80.19 mW/cm2 but then decreased to 46.00 mW/cm2 when the methanol feed increased to 4 M, due to the large amount of methanol crossover. • 1 wt% CHP functionalized 0.05 wt% GO/Nafion was used for DMFC. • The composite membrane was 1.86-fold higher durability than that of recast Nafion. • Power density was 1.34-fold higher than that of Nafion at 1 M methanol and 70 °C. • At 2 M methanol and 70 °C was the optimum condition for DMFC. [ABSTRACT FROM AUTHOR]

Stabilisation of metal species using hydroxyl‐rich dealuminated zeolites is a promising method for catalysis. However, insights into the interactions between the hydroxyl groups in zeolite and noble metals and their effects on catalysis are not yet fully understood. Herein, comparative studies were conducted using Pt catalysts supported on hydroxyl‐rich dealuminated Beta (deAl‐Beta) and the pristine proton‐form Beta (H‐Beta) for catalytic oxidation of toluene. The findings suggest that during impregnation the Pt precursor (i. e., Pt(NH3)4(NO3)2) interacted with different sites on deAl‐Beta and H‐Beta, leading to the formation of supported Pt nanoparticles with different physicochemical properties. In detail, for H‐Beta, the Pt precursor interacted with Al‐OH and isolated external Si‐OH sites, yielding Pt NPs with a higher Pt0 proportion of ~71 % compared to ~57 % Pt0 on deAl‐Beta. Comparatively, abundant hydroxyl groups on deAl‐Beta such as silanol nest and isolated internal Si‐OH stabilised highly active Pt‐O species. The resulting Pt/deAl‐Beta exhibited improved activity and anti‐coking ability than Pt/H‐Beta in catalytic toluene oxidation. For example, the temperature for 50 % toluene conversion was 193 °C for Pt/deAl‐Beta vs. 232 °C for Pt/H‐Beta, and the coke deposition was 1.7 % vs. 6.7 % (after the 24‐h longevity test), respectively. According to the toluene‐temperature programmed desorption (toluene‐TPD), 1H nuclear magnetic resonance (1H NMR) relaxation and in situ diffuse reflection Fourier transform spectroscopy (in situ DRIFTS) characterisation, the enhanced performance of Pt/deAl‐Beta could be ascribed to (i) the active Pt‐O sites stabilised by hydroxyl groups, which interact with toluene easily for conversion, and (ii) the acid‐free feature of the deAl‐Beta support, which avoids the formation of coke precursors (such as benzoate species) on the catalyst surface. Findings of the work can serve as the design guidelines for making effective supported metal catalysts using zeolitic carriers. [ABSTRACT FROM AUTHOR]

Nigerian kaolin is converted into pure zeolite-A by calcination of the kaolin at 650 °C for ten minutes, followed by mixing the obtained metakaolin with a zeolite seed, NaOH, and H2O (autoclave, 100 °C, 3 h). [ABSTRACT FROM AUTHOR]

A hierarchical structured composite made from clinoptilolite supported on date stones carbon is synthesized using two techniques. The composites are manufactured by fixing a natural zeolite (clinoptilolite) to the porous surface of date stones carbon or by direct hydrothermal synthesis on to the surface to provide a supported high surface area ion-exchange material for metal ion removal from aqueous streams. The fixing of the clinoptilolite is achieved using sucrose and citric acid as a binder. The composites and pure clinoptilolite were compared to test the efficacy for the removal of Sr 2+ ions from an aqueous phase. The encapsulation of the Sr 2+ using either vitrification or a geo-polymer addition was tested to ensure that the hazardous waste can be made safe for disposal. The hierarchical structured composites were shown to achieve a higher ion exchange capacity per gram of zeolite than the pure clinoptilolite (65 mg/g for the pure natural clinoptilolite and 72 mg/g for the pure synthesized clinoptilolite) with the synthesized composite (160 mg/g) having higher capacity than the natural clinoptilolite composite (95 mg/g). The rate at which the equilibria were established followed the same trend showing the composite structure facilitates diffusion to the ion-exchange sites in the zeolite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical ZSM-5 with siliceous shell is produced by chelation-alkaline treatment. • Microwave irradiation facilitates the chelation-alkaline treatment efficiently. • Catalytic HDPE pyrolysis is conducted over the hierarchical ZSM-5. • Kinetics and product quality of HDPE pyrolysis are improved over hierarchical ZSM-5. A new microwave (MW) assisted chelation-alkaline strategy was developed to produce hierarchical ZSM-5 zeolites (with external surface area of 203 m2/g) in minutes, leading to the formation of heterogeneous structure with a high-silica shell and aluminium-rich core (silicon-to-aluminium ratios of 49.2 and 37.6, respectively). The zeolites were assessed comparatively by catalytic pyrolysis of high-density polyethylene (HDPE). Compared to the mesoporous ZSM-5 zeolite prepared by the conventional alkaline treatment (via desilication by the NaOH aqueous solution), the hierarchical zeolite by the MW-assisted method showed comparable kinetics in catalytic pyrolysis of HDPE, but with the improved stability in the cyclic pyrolysis-regeneration tests. The improved stability could be due to the better-preserved structural integrity thanks to the relatively milder surface etching by the MW-assisted chelation dealumination method. In addition, compared to the parent ZSM-5, the product distribution of HDPE catalytic pyrolysis over the hierarchical ZSM-5 zeolite showed a higher portion of oil products (i.e., 12 wt% vs. 6.9 wt%) and an improved alkane-to-olefin ratio in the oil products (2.22 vs. 1.86, respectively) due to the reduced acidity and improved hydrogen transfer ability. The MW-assisted chelation-alkaline treatment could be a new strategy to regulate the trade-off between stability and activity of zeolites for catalytic applications. [ABSTRACT FROM AUTHOR]

• Operando synchrotron X-ray study on Phosphorus and Platinum migration. • Graphene-related-material applied as interventional materials for comparison. • X-ray Absorption Near Edge Structure applied to study chemical structural change. • Conducting mechanistic studies via the three-phase interface. • Performance and durability of high-temperature proton exchange membrane fuel cells. The application of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) addresses challenges in water management, fuel purity, and overheating under high current density. However, phosphoric acid (PA) migration hinders their development. This study uses synchrotron-based X-ray fluorescence spectroscopy to investigate PA and catalyst migration. Interventions with single-layer graphene and electrochemically exfoliated graphene oxide improve performance and durability. X-ray absorption spectroscopy provides insights into relevant mechanisms, advancing understanding of membrane electrode assembly preparation and the intricate influences of PA and catalyst migration on performance and durability in HT-PEMFCs. [ABSTRACT FROM AUTHOR]

Abstract: A series of composite membranes based on zeolite A and Nafion 117 have been fabricated for direct methanol fuel cells. The external surface of zeolite A has been modified to enhance the interface bonding between inorganic zeolite crystals and Nafion ionomer. The modified zeolite samples have been characterised using a combination of thermal analysis and spectroscopic techniques. Methanol permeability of Nafion 117 could be reduced by as much as 86% by incorporating functionalised zeolite NaA crystals into the membrane. The effect of different functionalisation level is discussed. [Copyright &y& Elsevier]

Utilizing of ash extracted from Iraqi common water reeds as an inexpensive effective silica source in the preparation of ZSM-5 zeolite was investigated for the first time in the present work. This study was conducted using a hydrothermal treatment at autogenous pressure. The molar content of silica (17.84–26.76), sodium oxide (1.71–2.4), water (76.92–304.6), organic template (0.55–2.73), organic solvent (23.46–140.76), and synthesis conditions (crystallization time (24–72 h) and temperature (130–180 °C)) were investigated to obtain high purity ZSM-5 zeolite microspheres. The zeolite samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis by X-Ray (EDAX), N 2 adsorption/desorption isotherms, Thermogravimetric Analyzer (TGA), and Fourier transform infrared spectroscopy (FTIR). XRD pattern of all synthesized samples was compared to XRD pattern of the commercial ZSM-5 zeolite. This work allows using locally available solid waste resulted from a dry natural plant as an inexpensive silica source without using an external source of silica. Also, this is the first report of the direct synthesis of a high purity ZSM-5 zeolite microspheres from common water reeds ash containing highly reactive silica. A gel composition of 2Na 2 O: 26.76SiO 2 : Al 2 O 3 : 2.73TPAOH: 23.46EtOH: 304.6H 2 O gave an outstanding final product of ZSM-5 zeolite microspheres at 180 °C and 27 h. This high crystallinity ZSM-5 zeolite porous microspheres possess Si/Al ratio of 17, a crystal size of 61.419 nm, BET surface area of 277.482 m2/g, a total pore volume of 0.1659 cm3/g, micropore volume of 0.1131 cm3/g, pore width of 5.28 nm, and hierarchical factor of 0.14. Image 1 • High purity ZSM-5 zeolite microspheres can be prepared using the ash extracted from common water reeds (CWRA). • Replacing the toxic chemicals with environmentally friendly silica source. • CWRA allows obtaining high purity ZSM-5 zeolite microspheres using low content of methanol and without the ageing step. • CWRA allows obtaining high purity ZSM-5 zeolite at lower crystallization temperature or shorter crystallization time. [ABSTRACT FROM AUTHOR]

A new and facile electrochemical exfoliation approach is proposed to produce better quality electrochemically exfoliated graphene with excellent high-temperature stability. The method is based on graphene exfoliation in inorganic electrolytes (e.g. (NH 4) 2 HPO 4 and (NH 4) 2 SO 4 and different combinations of these salts) where the electrolyte composition was found to have a significant impact on the yield, morphology, structure, and high-temperature stability of the graphene sheets. The graphene prepared using (NH 4) 2 HPO 4 electrolyte showed the lowest level of defects in comparison to the other electrochemically exfoliated graphene and an exceptional high-temperature stability in air, at temperatures of up to 750 °C; much higher than typical high surface area carbon materials which are unstable around 400 °C–500 °C in air. The addition of (NH 4) 2 SO 4 to the (NH 4) 2 HPO 4 electrolyte improved the exfoliation process and increased the production of single layer graphene sheets from 19% to ∼50%. These hybrid electrolytes also led to nitrogen, phosphorus, and sulphur tri-doped graphene sheets with a fewer defects and high-temperature stability in air. This simple process offers a promising approach for large scale preparation of doped graphene with fewer defects and exceptional properties for various applications. Image 1 [ABSTRACT FROM AUTHOR]

Methanol crossover through the proton exchange membranes of a direct methanol fuel cell (DMFC) significantly affects its performance and efficiency. Low methanol permeability and high proton conductivity of the membrane is desired for optimum performance. In this work, a multilayer (ML) membrane configuration prepared by a simple pressing technique is employed with and without the incorporation of sprayed cellulose nanocrystals (CNC) to achieve enhanced membrane properties. Assembled multilayer electrolytes show 19% enhanced maximum power density, while the addition of 1.5 wt% CNC (wt % of total final membrane) further improves the performance, giving a 38% better performance compared to standard Nafion N115. Methanol flux density and electrochemical impedance measurements attribute these improvement to the ~20% enhancement in the proton conductivity for the multilayer membrane which is enhanced further by an 11% reduction in methanol crossover when the cellulose nanocrystals are added. Image 1 • Economical and bio-degradable cellulose nanocrystals (CNC) as barrier material. • Multilayer (ML) membrane as the matrix for CNC with the thickness same as Nafion N115. • 11% reduction in the methanol crossover for ML–CNC–2 compared to N115. • ML–CNC–2 exhibits 38% improved DMFC performance compared to N115. • Lower crossover of ML–CNC–2 leads to possible size reduction of the overall technology. [ABSTRACT FROM AUTHOR]

Abstract Hydrophobic polyvinylidene fluoride (PVDF) membranes have been successfully used in membrane distillation (MD) for desalination applications; however, there is still room for performance enhancements both regarding water flux and salt rejection. In this work, reduced graphene oxide (rGO) nanoplatelets with different degrees of reduction (36%, 58%, 65 and 69% removal of oxygen, as characterized by XPS) were incorporated as fillers in PVDF matrices in order to evaluate the effect of the oxygen content of the fillers in the MD performance. UV–Vis and Raman spectroscopies were also used to characterize the fabricated rGO. Changes in morphology of the prepared mixed matrix membranes (MMMs) were assessed via scanning electron microscopy (SEM) and were related to the increased hydrophilicity and viscosity of the casting solutions when fillers were added. MMMs containing 0.5 wt% rGO with an optimum degree of reduction of 58% exhibited an improved MD performance, with fluxes of ~7.0 L m−2 h−1 (LMH), representing an enhancement of ~169% in comparison with the plain PVDF membrane, without compromising salt rejection (>99.99%). Continuous testing for up to 96 h showed a stable performance of the developed MMMs, without compromising the quality of the permeate. Graphical abstract Unlabelled Image Highlights • Reduced graphene oxide (rGO) nanosheets with different degrees of reduction were synthesized. • Mixed matrix membranes (MMMs) containing rGO nanosheets in PVDF were prepared. • The effect of reduction degree on membrane distillation performance was investigated. • The MMMs showed increased water flux and high salt rejection. [ABSTRACT FROM AUTHOR]

Abstract Thin film nanocomposite (TFN) membranes of polymer of intrinsic microporosity PIM-1 incorporating graphene oxide (GO) nanosheets of different sizes and chemistries are presented. These membranes show an improved separation performance for the recovery of n -butanol from aqueous solutions through pervaporation; an improvement of ca. a third of the value achieved for pristine PIM-1 thin films is obtained for TFN membranes filled with nanometer-sized reduced octyl-functionalized GO. In addition, these nanometer-sized fillers lead to a maximum increase in total flux of approximately 40%. The thickness of the supported films is in the range 1–1.5 µm, and fillers used are micrometer- and nanometer-sized alkyl-functionalized GO nanosheets and their chemically reduced counterparts. As evidenced by a superior overall membrane performance, the interfacial interaction between the filler and the polymer matrix is enhanced for those whose lateral size is in the nanometer range. Moreover, an enhancement in the separation performance and productivity of such membranes is observed for higher operating temperatures and higher contents of n -butanol in the feed. Graphical abstract fx1 Highlights • PIM-1/alkyl-functionalized graphene thin film nanocomposite (TFN) membranes were prepared. • TFN membranes were tested for n-butanol recovery from aqueous solutions via pervaporation. • The addition of nano-sized fillers improved the separation performance of PIM-1 thin film membranes. • Nano-sized fillers enhanced the total flux up to approximately 40%. [ABSTRACT FROM AUTHOR]

Recent research has demonstrated a new synthesis route for hierarchically porous zeolite composites by mechanical modification of the support surface using ultrasonication in a nanoparticle suspension. It was believed that target zeolites should be added as seeds for the sonication. In this study, the effect of nanoparticles was investigated with ultrasonication to understand the crystallization mechanism of zeolites obtained by the nanoparticles–assisted synthesis. It has been found that the nanoparticles under the influence of ultrasonication generate fissures or cracks as nucleation sites on the carbon surface. These nanoparticles such as zeolite A, γ-Al 2 O 3 , quartz and sand are different from the target zeolite X. Therefore, an amorphous aluminosilicate gel nucleates at those cracks during the hydrothermal treatment. Thus, the mechanical activation of the support surface is the process to induce the formation of strongly attached zeolite X over the template, not a seeding step. This is confirmed as an attachment due to the weak bond between the support and the zeolite for ‘non-seeded’ composites whereas the ‘seeded’ composites have a robust structure which maintains a zeolite coating upon mechanical agitation. [ABSTRACT FROM AUTHOR]

In this work, composite membranes for a direct methanol fuel cell (DMFC) were prepared using a spraying method to improve cell performance especially at a high methanol concentration. Nafion polymer and mordenite as a filler were used for the composite membrane preparation using a spraying method and a conventional solution casting method and the membranes from the two methods were compared. SEM images showed that a more homogeneous composite membrane could be obtained using the spraying method. The effect of mordenite content was also studied. The membranes were consequently characterized and tested in DMFC operation. The results were compared to those prepared using the solution casting method at 30, 50, and 70 °C with methanol concentrations of 2, 4, and 8 M. It was found that the membrane with 5 wt.% mordenite from the spraying method showed a vast improvement in DMFC performance. When the cell was operated at 70 °C, the maximum power density of 5 wt.% mordenite from the spraying method was higher than that of commercial membrane and 5 wt.% from the solution casting method. Power densities from the 5 wt.% sprayed membrane were higher by around 29%, 40%, and 60% at 2, 4, and 8 M methanol concentration, respectively. [ABSTRACT FROM AUTHOR]

Air gap membrane distillation (AGMD) is an emerging desalination technology with the potential to meet the challenge of global water scarcity due to its low cost and high thermal efficiency compared to other processes. However, despite the potential of AGMD, a lack of appropriate membranes limits its commercial application. Therefore, this study was focussed on the fabrication of high flux, robust membranes for the purification of artificial sea water by incorporating graphene oxide functionalized with 3-(aminopropyl)triethoxysilane (APTS) into PVDF polymer solutions. Successful functionalisation of GO with APTS was confirmed with XPS and FTIR. It was shown that the addition of GO and GO-APTS enhanced the permeate flux by 52% and 86%, respectively, compared to pure PVDF. The best performing membrane contained 0.3 wt% GO-APTS (with respect to PVDF) and had a flux of 6.2 LMH (L m −2 h −1 ) whilst maintaining perfect salt rejection (>99.9%). These improvements were attributed to increased surface and bulk porosity, larger mean pore size and hydrophilic interactions owing to the functional groups of GO and GO-APTS. These membranes are evidence of the potential that GO and related materials have as nanocomposite fillers in high performance desalination membranes. [ABSTRACT FROM AUTHOR]

Microwave-assisted synthesis of zirconium (Zr) based metal organic frameworks (MOFs) were performed and the yield and porous property of UiO-67 was optimized by varying the quantity of the modulator (benzoic acid, BenAc and hydrochloric acid, HCl), reaction time and temperature. It was found that ( i ) an increase in the amount of modulator enhanced the specific surface area and pore volume of UiO-67 due to the promotion of linker deficiency; and ( ii ) the presence of modulators influenced the number of nuclei (and hence the crystal size) and nucleation time (and hence the yield). Optimum amounts of BenAc and HCl for synthesizing UiO-67 under microwave irradiation were determined as 40 mol equivalent and 185 mol equivalent (to Zr salt), respectively. In comparison to conventional solvothermal synthesis, which normally takes 24 h, microwave methods promoted faster syntheses with a reaction time of 2–2.5 h (at similar temperatures of 120 °C and 80 °C for BenAc and HCl, respectively). The thermal effect of microwave is believed to contribute to the fast synthesis of UiO-67 in the microwave-assisted synthesis. The reaction mass efficiency and space-time yield show that microwave heating promoted the simple yet highly efficient preparation of Zr-based MOFs. In addition, UiO-67 MOFs from different synthesis methods ( i.e. the microwave-assisted and solvothermal method) were evaluated using single-component (CO 2 and CH 4 ) adsorption, showing comparable gas uptakes. [ABSTRACT FROM AUTHOR]

In this work, graphene oxide (GO) was combined with polyethersulfone (PES) to form mixed matrix membranes (MMMs) for ultrafiltration of aqueous solutions. Also, the effect of adding various pore formers (poly(vinylpyrrolidinone (PVP), reverse triblock Pluronic (P31R1), and poloxamine Tetronic (T904)) to the dope solution was investigated. The prepared MMMs were characterised using various techniques, including Fourier-transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy. It was found that the incorporation of 0.5 wt% of GO increased the flux from 2 to 13 L m −2 h −1 (LMH) and the rejection of bovine serum albumin (BSA) from 89.2 to 97% compared to benchmark PES membranes. SEM analysis revealed the increased pore size and porosity of the GO modified membranes, which contributed to the increased flux. The addition of pore formers further increased the flux compared to pure PES and also displayed synergistic effects with GO. The combination of T904 with 0.3 wt% GO increased the water flux significantly from 2 to 245 LMH and increased the rejection of acridine orange (from 40.5 to 48.4%) and BSA (from 89.6 to 93.3%), respectively. Also, fouling properties of the membranes were investigated with the parameters: flux recovery ratio ( FRR ), total flux decline ratio ( R t ), reversible flux decline ratio ( R r ), and irreversible flux decline ratio ( R ir ), and improved anti-fouling properties were obtained with the addition of GO. This work shows the promise of GO as a performance-enhancing additive in MMMs for wastewater treatment. [ABSTRACT FROM AUTHOR]

The aim of this work was to improve proton exchange membranes (PEMs) used in direct methanol fuel cells (DMFCs). A membrane with a high proton conductivity and low methanol permeability was required. Zeolite filler in Nafion (NF matrix) composite membranes were prepared using two types of zeolite, mordenite (MOR) and analcime (ANA). Spray method was used to prepare the composite membranes, and properties of the membranes were investigated: mechanical properties, solubility, water and methanol uptake, ion-exchange capacity (IEC), proton conductivity, methanol permeability, and DMFC performance. It was found that MOR filler showed higher performance than ANA. The MOR/Nafion composite membrane gave better properties than ANA/Nafion composite membrane, including a higher proton conductivity and a methanol permeability that was 2–3 times lower. The highest DMFC performance (10.75 mW cm −2 ) was obtained at 70 °C and with 2 M methanol, with a value 1.5 times higher than that of ANA/Nafion composite membrane and two times higher than that of commercial Nafion 117 (NF 117). [ABSTRACT FROM AUTHOR]

Direct methanol fuel cells (DMFCs) suffer from performance reduction due to mass transport losses incurred at high current regions. In this work, we report the use of activated carbon (AC), prepared from factory waste-tea, as cathode microporous layer in the membrane electrode assembly (MEA) of a DMFC, alleviating this mass transport effect. This biomass based AC framework, when tested under fuel cell operating conditions provided 0.25 V @ 300 mA cm −2 , enhancing cell performance by 33% over standard electrodes at 70 °C. During uninterrupted durability testing, this electrode displayed exceptional stability in mass transport dominated region, with loss of 15 mV day −1 , compared to 25 mV day −1 loss for the standard. Sample and electrode characterization measurements reveal that pore size distribution/particle size characteristics coupled with hydrophobic nature of the synthesized activated carbon, contributed to the performance improvement. [ABSTRACT FROM AUTHOR]

Hierarchical ZSM-5 coatings supported on macrocellular β-SiC foams were prepared by a microwave-accelerated secondary growth method. Under microwave irradiation, differential heating was enabled due to the high microwave-adsorbing ability of SiC leading to the fast assembly of ZSM-5 zeolites on the SiC foams. The effects of crystallisation temperature, time and agitation on the growth of ZSM-5 zeolites on SiC foams were also investigated under microwave heating. A specific surface area of ca. 52 m 2 g −1 was obtained under the optimum condition of 150 °C and 4 h. Comparative studies of conventional hydrothermal and microwave-accelerated synthesis were conducted and the resulting materials were characterised extensively using XRD, SEM and N 2 adsorption. The combination of microwave heating, high microwave absorption of SiC substrates and agitation allowed a much more focused heating across the surface of SiC foams than conventional heating, which suppressed the formation of ZSM-5 crystals in the liquid phase and the consequent sedimentation. Additionally, for the first time, mesoscopic features of ZSM-5 coatings on SiC foam composites (>10 μm) were studied in 3D by X-ray micro computed tomography (μ-CT), providing quantitative information on the quality of the ZSM-5 coating such as the global thickness and distribution of ZSM-5 across the SiC foam supports. It was concluded that microwave-accelerated secondary growth synthesis offered an efficient route to give high quality coatings on structured foams with the good crystal quality and uniform thickness as well as lower energy consumption, especially for the substrate with a high loss tangent. [ABSTRACT FROM AUTHOR]

Energy production from direct alcohol fuel cells depends strongly on the operating conditions. In this paper, the aim was to find the best conditions of direct methanol fuel cells (DMFC) and direct ethanol fuel cells (DEFC) to obtain the maximum power density with the response surface method using Program Design Expert 7.0.0. Three related independent variables, including operating temperature in the range of 30–70 °C, alcohol flow rate in the range of 5–50 ml/min, and alcohol concentration in the range of 0.5–3 M, were covered. Nafion117 was used as an electrolyte and Pt-Ru and Pt were used as catalysts in anode and cathode, respectively. The effect of those variables on the maximum power density was illustrated in the form of quadratic models which predicted the appropriate operating conditions. The Nafion membrane was modified by adding mordenite (MOR) to improve its alcohol permeability. The result from response revealed that the higher operating temperatures and higher alcohol concentrations led to an increase in maximum power density, in both the DMFC and DEFC. The DMFC had a higher maximum power density and greater current than the DEFC had. This was because methanol was easier to oxidize than ethanol In addition, it was found that the MOR content of 1.47 wt% in the Nafion composite membrane reduced the alcohol permeability and resulted in a higher power density. Therefore, the model suggested the optimum conditions to produce greener energy (less resource use with high energy produced). [ABSTRACT FROM AUTHOR]

PIM-1-based freestanding mixed matrix membranes (MMMs) and thin film nanocomposites (TFNs) were prepared by incorporating porous silica nanosheets (SN) and exfoliated SN (E-SN) derived from natural vermiculite (Verm) in the PIM-1 polymer matrix. In addition, SN were functionalized by sulfonic acid and amine groups (S-SN and N-SN, respectively) and were also used as fillers for the preparation of MMMs. The gas separation performance was evaluated using CO 2 /CH 4 and CO 2 /N 2 (1:1, v:v) binary gas mixtures. Among freestanding membranes, fresh ones (i.e. tested right after preparation) containing 0.05 wt% functionalized SN and E-SN outperformed the neat PIM-1, surpassing the 2008 Robeson upper bound. At the same filler concentration, fresh MMMs with sulfonic acid-functionalized SN (S-SN) exhibited 40% higher CO 2 permeability, 20% higher CO 2 /N 2 selectivity and almost the same CO 2 /CH 4 selectivity as neat PIM-1 membranes. Moreover, after 150 days of aging, these membranes were capable of maintaining up to 68% of their initial CO 2 permeability (compared to 37% for neat PIM-1). When prepared as TFN membranes, the incorporation of 0.05 wt% of S-SN led to 35% higher initial CO 2 permeance and five times higher CO 2 permeance after 28 days. [Display omitted] • Freestanding and thin PIM-1-based films were fabricated using silica nanosheets (SNs). • The prepared MMMs and TFNs were tested for CO 2 /N 2 and CO 2 /CH 4 separation. • PIM-1/sulfonated SNs (0.05 wt%) showed the best initial performance. • The incorporation of SNs partially prevented aging in both TFNs and MMMs. [ABSTRACT FROM AUTHOR]

• Defect-free ZIF-8/GO/PIM-1 thin-film nanocomposite (TFN) membranes were fabricated. • 2D ZIF/GO was produced by in situ growth of ZIF-8 on GO sheets as a continuous, uniform and thin layer. • ZIF-8/GO composite results in high dispersity and compatibility of ZG within PIM-1. • PIM-1 infiltration into PVDF substrate was avoided by water pre-impregnation. • ZIF-8/GO/PIM-1 TFN membranes display a high PSI (228 kg m−2h−1). In this work, thin film nanocomposite (TFN) membranes of super-glassy polymer PIM-1 containing zeolitic imidazolate framework-8 (ZIF-8)/graphene oxide (GO) composites (ZG) have been prepared by dip-coating onto water pre-impregnated polyvinylidene fluoride (PVDF) substrates. Higher flux and improved separation factors as compared to bare PIM-1 thin film composite (TFC) membranes have been achieved in organophilic pervaporation; for an aqueous feed solution with 5 wt% of butanol at 65 °C, a total permeate flux of 7.9 ± 0.69 kg m−2h−1 and a separation factor (β BtOH/H2O) of 29.9 ± 1.99 have been obtained with a TFC membrane containing 0.5 wt% of ZG filler. The pervaporation separation index (PSI) of this membrane (228 kg m−2h−1) is amongst the highest values reported in the literature. This excellent performance is attributed to the formation of a defect-free PIM-1 active layer (<1 μm) and the hydrophobic nature of the ZG fillers. [ABSTRACT FROM AUTHOR]

Graphite intercalation compounds (GIC) can be used as adsorbents for the removal of dissolved organic contaminants in water, and can be rapidly regenerated by electrochemical treatment. After electrochemical regeneration, the adsorption capacity of the GIC is often observed to increase compared to fresh adsorbent. This increase has been attributed to roughening of the surface as well as changes in surface chemistry. Specific surface areas of fresh and electrochemically treated GICs have been measured, and show no significant variation. Consequently, the electrochemical anodic oxidation process used to regenerate the material has been investigated, and these changes, specifically the transformation of the oxygen containing functional groups which is believed to give the GIC its surface chemistry properties, has been measured and studied. Analytical techniques including Scanning Electron Microscopy, Attenuated Total Reflectance Fourier Transform Infra-red spectroscopy, X-ray Photoelectron spectroscopy, Energy Dispersive X-ray spectroscopy and Boehm titrations were used to detect and estimate the relative amounts of functionalities such as carboxylic, quinone and lactonic functional groups. Results showed that fresh GICs have acidic quinone and carboxyl groups on the surface. These functional groups increase upon regeneration, however sustained regeneration leads to the formation of basic lactones which offset the relative amounts of the acidic groups. Acidic functional groups have been reported to increase adsorption, and consequently, there is an initial increase in adsorption due to surface acidic functionalities. Subsequent regeneration leads to the formation of basic functional groups which limit this enhanced adsorption. [ABSTRACT FROM AUTHOR]

To improve the performance and durability of phosphoric acid (PA) doped polybenzimidazole (PBI) membranes in high–temperature proton exchange membrane fuel cells (HT–PEMFCs), in this work, as–received natural muscovite (Mus), a clay material, was successfully incorporated into PBI matrix as an inorganic filler through the doctor blade method. The amount of Mus was varied (0.5–2 wt%) to explore its impact on the proton conductivity, mechanical and dimensional stability, power density, durability, and acid retention ability of the composite membranes. As the incorporation of Mus into membranes can introduce interactions with polymer chains and PA molecules to afford additional proton transport pathways at the interfaces in Mus–PBI and Mus–PA crosslinks, the membrane with 1 wt% Mus showed highest power density of 586 mW cm−2 at 150 °C without humidification, 24% higher than the pure PBI membrane (474 mW cm−2). Meanwhile, the PA doped composite membrane with 1 wt% Mus also displayed the highest mechanical strength (7.5 MPa) and lowest dimensional swelling (70.99% in area swelling and 202% in volume swelling). Compared with the pristine PBI membrane, the composite membranes had significantly improved durability under accelerated stress test (AST). The decreased ohmic resistance and increased polarization resistance after AST are related to the membrane thinning and the loss of catalyst active area, respectively. Most importantly, it was found that the strong interactions between Mus and PA molecules lead to improved acid retention ability of the composite membranes, thus less leached acid from the composite membrane reduces the negative effects on the catalyst degradation to alleviate degradation on cell performance and durability. [Display omitted] • Natural muscovite was successfully incorporated into PBI membranes using the doctor blade method. • The prepared composite membranes show better power density and durability than the pure PBI membrane. • The interactions between Mus and PA explored by EDS, TGA and XPS benefit improved acid retention ability. [ABSTRACT FROM AUTHOR]

Abstract: Composite polymer proton exchange membranes (PEM) were prepared by solution recasting. The composite membranes formed are based on Nafion incorporating a silane functionalized zeolite, mordenite, as an additive. The composite membranes were placed within a single cell DMFC and compared to an MEA featuring a standard Nafion 125μm membrane. The impact of mordenite particle size, the choice of the silane functionalizing agent and the membrane preparation procedure are investigated. A composite ion exchange membrane which featured Nafion and a ground mordenite which was functionalized using glycidoxypropyltrimethoxysilane achieved a power density that outperformed a standard Nafion MEA under all conditions. [Copyright &y& Elsevier]

A machine-learning approach is used to segment 14 X-ray computed-tomography datasets acquired by lab-based scanning of laser-milled, high-temperature polymer electrolyte fuel cell samples mounted in a 3D-printed sample holder. Two modes of operation, one with constant current load and the other with current cycling, are explored and their impact on microstructural change is correlated with electrochemical performance degradation. Constant-current testing shows the overall quantity of phosphoric acid in the gas diffusion layers is effectively unchanged between 50 and 100 h of operation but that inter-electrode distribution becomes less uniform. Current-cycling tests reveal similar quantities of phosphoric acid but a different intra-electrode distribution. Membrane swelling appears more pronounced after current-cycling tests and in both cases, significant catalyst layer migration is observed. The present analysis provides a lab-based approach to monitoring microstructural degradation in high-temperature polymer electrolyte fuel cells and provides a more accessible and more statistically robust platform for assessing the impact of phosphoric acid mitigation strategies. • Lab-based X-ray micro-computed tomography to investigate phosphoric acid leaching. • Machine learning segmentation yields quantification of microstructural changes. • Electrochemical performance loss linked to microstructure evolution. • Redistribution of phosphoric acid depends on fuel cell operation mode. • Accelerated stress tests give more membrane swelling and less uniform Pt migration. [ABSTRACT FROM AUTHOR]

Reduced electrochemically exfoliated graphene oxide (rEGO) is combined with carbon black (CB) as a hybrid support material to improve platinum (Pt) catalyst electrochemical activity and durability. Pt/rEGO 2 -CB 3 (rEGO/CB ratio 2/3) retains 71% of initial electrochemical surface area (ECSA) and maintains higher oxygen reduction reaction (ORR) activity compared to Pt/CB after 30000 cycles of the accelerated stress test (AST). In addition, Pt/rEGO 2 -CB 3 shows a 1.8 times improvement in the hydrogen fuel cell performance compared with Pt/CB and is more stable after 24 h at a continuous 0.60 V. The Pt/rEGO 2 -CB 3 promotes the 4e− reaction pathway demonstrated by linear sweep voltammetry (LSV), which leads to greater ORR activity. In addition, the combination of rEGO and CB leads to both enhanced transport properties and improved stability. The Pt particles on both CB and rEGO are less likely to agglomerate in the composite support than in either of the two carbon supports when used alone. Pt supported on a hybrid support combining electrochemically exfoliated graphene oxide and carbon black (Pt/rEGO 2 -CB 3) achieved 1.8 times improved performance and higher durability compared with Pt supported on a single carbon black (Pt/CB). [Display omitted] • Nano-sized graphene oxide were prepared by electrochemical exfoliation method. • The structured support combining EGO and carbon black relieves mass transfer issue. • Pt/rEGO 2 -CB 3 significantly improves PEMFC performance with high durability. [ABSTRACT FROM AUTHOR]

We report a low-cost, highly energy efficient microwave-assisted chelation (MWAC) method, which enabled the post-synthetic modification of synthetic zeolites for adopting hierarchical structures within minutes. Exemplified by Zeolite Y, hierarchical Y zeolites prepared in this way showed exceptional specific external surface areas of >300 m2 g−1 and mesopore volumes of >0.46 cm3 g−1. Comparative assessments revealed that developed zeolites have shown significantly improved catalytic activities for catalysis involving large substrates, such as catalytic cracking and hydrocracking of plastics. Image 1 • Efficient post-synthetic modification method under microwave irradiation for making hierarchical Y zeolites. • Combination of microwave and chelation to make intracrystalline mesopores in Y zeolites. • The developed method shows significantly reduced energy consumption and improved mesoporosity. • The resulting hierarchical Y zeolites show the improved catalytic activities in catalytic cracking and hydrocracking. [ABSTRACT FROM AUTHOR]

A multiporous zeolite A (A b) was obtained by the addition of the organosilane molecule dimethyl octadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC) in the synthesis gel and successfully dispersed in bacterial cellulose forming aerogels for Pb2+ adsorption. Several characterization techniques such as powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N 2 adsorption-desorption were employed to investigate physical, chemical, and textural properties of the samples. The resulting material is also compared to the conventional microporous zeolite A and shows a positive interaction between zeolite crystals and cellulose nanofibrils, specially when the mesopores are present in the crystal. Improvements are observed for the multiporous samples in both adsorption and ionic exchange processes. The selectivity for Pb2+ in the presence of Cd2+ is enhanced as a result of improved intraparticle diffusion where there is the insertion of mesopores to the structures. From the kinetic models, the pseudo-second order model fits better to the experimental data suggesting chemisorption as the governing process in adsorption and the mesopores seem to have a remarkable role on it. These multiporous materials facilitate the access of Pb2+ to the zeolite inner pores and therefore present high potential to be used for both Pb2+ adsorptive and analytical devices. Image 1 • Multiporous zeolite A is successfully obtained by using a bifunctional surfactant. • Hierarchical materials are obtained with Bacterial cellulose nanofibres. • Better selectivity for Pb2+ in binary system with Cd2+ is achieved for the material. • Materials with potential use for both adsorptive and analytical devices. [ABSTRACT FROM AUTHOR]

The application of three-dimensional (3D) pillared-layer metal-organic frameworks (MOFs) M(bdc)(ted) 0.5 (M = Co, Cu, Ni, Zn) in the adsorptive separation of ethane/ethylene (C 2 H 6 /C 2 H 4) mixtures was studied. The effect of the type of metals in M(bdc)(ted) 0.5 on the framework structure regarding the moisture stability and adsorption performance was investigated. M(bdc)(ted) 0.5 MOFs show excellent porous structures with high surface areas of up to 1905 m2/g (M = Ni), as well as being stable under humid conditions (assessed by the dynamic water vapour adsorption tests with maximum 20% relative humidity at 25 °C). M(bdc)(ted) 0.5 exhibits the preferential adsorption of C 2 H 6 over C 2 H 4 under all conditions (i.e. 25–50 °C and 0–10 bar), although a reversal in adsorption uptake (i.e. C 2 H 4 adsorption uptake exceeds the amount adsorbed of C 2 H 6) occurs at pressures of >6 bar. The adsorption capacities of C 2 H 6 and C 2 H 4 on M(bdc)(ted) 0.5 adsorbents are up to 8.63 and 8.79 mmol/g at 25 °C and 10 bar, respectively. The calculated C 2 H 6 /C 2 H 4 selectivity for an equimolar mixture is insensitive to the metal ions in M(bdc)(ted) 0.5 , which varies between 1.4 and 1.9. Dynamic breakthrough experiments show that C 2 H 6 /C 2 H 4 mixture can be separated in a fixed bed packed with Ni(bdc)(ted) 0.5. The good adsorption capacity and selectivity, as well as the low isosteric heat of adsorption, make M(bdc)(ted) 0.5 MOFs, especially Ni(bdc)(ted) 0.5 , good candidates to be further developed for the effective separation of C 2 H 6 /C 2 H 4 mixtures in the presence of water vapour with a relative humidity lower than 30%. Image 1 • Pillared-layer M(bdc)(ted) 0.5 MOFs show selective adsorption of C 2 H 6. • Adsorption capacity of M(bdc)(ted) 0.5 for C 2 H 6 is up to 8.63 mmol/g at 25 °C and 10 bar. • Adsorption capacity, rather than selectivity, of M(bdc)(ted) 0.5 depends on metal ions. • M(bdc)(ted) 0.5 MOFs are moisture-stable at 20% relative humidity at 25 °C. [ABSTRACT FROM AUTHOR]

• Polyethersulfone (PES) membranes comprising graphene oxide (GO) were prepared. • 3-aminopropyltriethoxysilane functionalized GO (APTS-GO) fillers were added to PES. • Better rejections for dyes and salts were obtained for the mixed matrix membranes (MMMs). • A 6-fold increase in water flux was achieved by adding pore formers along APTS-GO. • A reduction in fouling propensity is obtained for membranes containing APTS-GO. In this study, graphene oxide (GO) functionalized with 3-aminopropyltriethoxysilane (APTS) was incorporated into polyethersulfone (PES) membranes prepared by non-solvent induced phase inversion (NIPS). This resulted in increased rejections of protein bovine serum albumin (BSA), divalent salts (MgSO 4) and low-molecular weight dyes (sunset yellow and acridine orange). The structural properties of the prepared mixed matrix membranes (MMMs) as well as pure PES control membranes were investigated through scanning electron microscopy (SEM), atomic force microscopy (AFM), specific surface area, zeta potential and contact angle. It was found that the introduction of APTS-GO fillers in the polymer matrix made the membranes' application range move from ultrafiltration (UF) for pure PES membranes to nanofiltration (NF) for MMMs with a molecular weight cut off (MWCO) of ~1000 Da. Furthermore, membranes prepared by using only 0.1 wt% APTS-GO in combination with 1 wt% of pore-forming agent polyvinylpyrrolidone (PVP 40 K) in the casting solution exhibited high water permeance values of 9.9 LMHbar (L m−2 h−1 bar−1) at low operating pressures of 4 bar and rejections of dyes and BSA > 95%. In addition, improved anti-fouling properties and tensile strength values were obtained when incorporating the functionalized GO. [ABSTRACT FROM AUTHOR]

• Plasma-assisted dry reforming of methane (DRM) over UiO-67 MOF-based catalyst. • UiO-67 material in the discharge zone improved the plasma generation and gas-phase reactions. • Pt nanoparticles supported on UiO-67 promoted surface reactions, improving DRM. • PtNP@UiO-67 catalysts were robust and stable in the plasma-assisted catalytic DRM. Plasma-assisted dry reforming of methane (DRM) was performed in a dielectric barrier discharge (DBD) reactor. The effect of different packing materials including ZrO 2 , UiO-67 MOF and PtNP@UiO-67 on plasma discharge was investigated, showing that ZrO 2 suppressed the plasma generation while UiO-67 improves it due to its porous nature which favours the formation of filamentary microdischarges and surface discharges. The improved plasma discharge increased the conversion of CH 4 and CO 2 by about 18% and 10%, respectively, compared to the plasma-alone mode. In addition, the distribution of hydrocarbon products changed from dominant C 2 H 6 in the plasma-alone mode to C 2 H 2 and C 2 H 4 in the UiO-67 promoted plasma-assisted DRM. The UiO-67 MOF was stable in plasma, showing no significant changes in its properties under different treatment times, discharge powers and gases. Pt nanoparticles (NPs) on UiO-67 improved plasma-assisted DRM, especially the selectivity due to the presence of surface reactions. Due to the dehydrogenation of hydrocarbons over Pt NPs, the selectivity to hydrocarbons decreased by 30%, compared to the UiO-67 packing. In situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) was carried out to probe the surface reactions on PtNP@UiO-67 catalyst, showing the decomposition of surface formats to CO and C 2 H 4 dehydrogenation over the metallic Pt. The PtNP@UiO-67 catalyst showed good reusability in the plasma-assisted DRM, and H 2 production was improved by high CH 4 /CO 2 molar ratio and low feed flow rate. [ABSTRACT FROM AUTHOR]

The effect of alcohol ratio in solution casting of composite membranes is one of the important factors to their good properties for direct methanol fuel cell (DMFC). The investigation was focused on the effect of alcohol ratio (methanol/ethanol mixture) during the fabrication process on the membrane properties, morphology, chemical resistance, water uptake, proton conductivity and methanol permeability. Alcohol mixture with proportion of 0–5 vol ratio was varied in order to prepare the composite membranes. It was found that the alcohol ratio had insignificant effect on the homogeneity of the composite membranes as the layers of polymer rich and mordenite rich were formed. The ratio had insignificant effect on proton conductivity of the composite membranes. Reducing alcohol ratio from five to three, however, led to 80% chemical resistance reduction and 70% higher methanol permeability. Finally, these composite membranes with five volume ratio of alcohol were used in membrane electrode assembly and tested in a DMFC compared to recast Nafion membrane. The composite membranes gave a maximum power density of 11.5 mW cm−2 at 343.15 K, which was 58% higher than that of recast membrane. • Effect of solvent in solution cast method for composite membrane fabrication was studied. • Amount of solvent in fabrication did not affect filler dispersion. • The higher amount of alcohol in membrane fabrication leads to higher DMFC performance. [ABSTRACT FROM AUTHOR]