Porosity Of Support Research Articles

Cu (ii) Immobilized on Mesoporous Poly (Guanidine–Triazine–Sulfonamide) (PGTSA/Cu): A New Catalyst for the Synthesis of Tetrazolo[1,5‐a]pyrimidines

ABSTRACTThe study focuses on the synthesis and characterization of a new mesoporous polysulfonamide stabilizer using condensation polymerization and the nanocasting technique. The resulting material, PGTSA, was modified with copper ions and used as a nanocatalyst in the reaction of benzaldehydes, 1H‐tetrazole‐5‐amine, and malononitrile. The performance of the mesoporous PGTSA/Cu (II) was compared with non‐porous PGTSA/Cu (II), highlighting the significance of support porosity in catalytic activity and loading of copper species. Based on the analysis of the ICP and catalytic performance, it was observed that mesoporous PGTSA/Cu (II) exhibited a higher level of catalytic activity compared to PGTSA/Fe3O4/Cu (II) and non‐porous PGTSA/Cu (II). Also, the catalytic activity of the aryl aldehyde was significantly influenced by its electrical characteristics. The recovery and reusability of the PGTSA/Cu (II) catalyst are noteworthy aspects, highlighting the practicality and sustainability of the catalytic system. The amount of copper in fresh catalyst and the recycled catalyst after six times recycling is 1.57% and 1.52%, respectively. Therefore, ICP‐OEIS analysis indicated that copper leaching of this catalyst is very low. The procedure offered high product yields, easy recovery of the nanocatalyst, remarkable reusability, short reaction times, and compatibility with various substrates.

Glycerol Carbonate Production via Transesterification: The Effect of Support Porosity and Catalyst Basicity

Glycerol transesterification with diethyl carbonate (DEC) using catalysts with different porosities as support for CaO was performed, seeking the evaluation of how textural properties influence glycerol conversion and product selectivity. A total of 20% CaO was supported on ZSM-5, K-10, MCM-41, SiO2, and γ-Al2O3. Catalysts showed a well-dispersed active phase of CaO in all the supports and no changes in the support crystalline structure were noticed. Reactions were performed in dimethyl sulfoxide (DMSO), 10 wt.% of catalyst in relation to glycerol, at 130 °C, and 1:3 glycerol/DEC molar ratio. According to our results, the higher the pore volume and pore size, the higher the glycerol conversion. On the other hand, concerning selectivity, higher glycerol carbonate selectivities were reached when strong basic sites were present. A total of 86% glycerol conversion and 91% glycerol carbonate selectivity were found using 60% CaO supported on γ-Al2O3 after 5 h of reaction.

Tailoring porosity: Unveiling the ideal alumina support (aerogel, xerogel, cryogel) for high-performance CO2 capture with polyethylene glycol

This study investigates enhancing CO2 capture through high polyethylene glycol (PEG) loading on alumina aerogel (Al2O3-A), comparing it with alumina cryogel (Al2O3-C) and xerogel (Al2O3-X). Focusing on sustainable carbon capture and storage (CCS), the research optimizes PEG’s CO2 adsorption by adjusting the porosity of these alumina supports. Key characterization techniques, including XRD, FESEM, FTIR, and N2 adsorption-desorption analysis, were utilized. The study evaluated the effects of pressure, temperature, and PEG loading on CO2 capture capacity using response surface methodology (RSM). Optimal conditions (25 °C, 9.0 bar, 61.0 % PEG) achieved a CO2 adsorption capacity of 443 mg/g. The Hill model was most effective in describing the CO2 adsorption, while the fractional order model accurately depicted the kinetics. Thermodynamic analysis confirmed that the adsorption process is spontaneous, exothermic, and physical. The results underscore the potential of PEG/Al2O3-A for effective CO2 capture, highlighting its high stability, capacity, and reusability, and advancing sustainable carbon capture technologies.

Carbon-Supported Fe-Based Catalyst for Thermal-Catalytic CO2 Hydrogenation into C2+ Alcohols: The Effect of Carbon Support Porosity on Catalytic Performance

Carbon materials supported Fe-based catalysts possess great potential for the thermal-catalytic hydrogenation of CO2 into valuable chemicals, such as alkenes and oxygenates, due to the excellent active sites’ accessibility, appropriate interaction between the active site and carbon support, as well as the excellent capacities in C-O bond activation and C-C bond coupling. Even though tremendous progress has been made to boost the CO2 hydrogenation performance of carbon-supported Fe-based catalysts, e.g., additives modification, the choice of different carbon materials (graphene or carbon nanotubes), electronic property tailoring, etc., the effect of carbon support porosity on the evolution of Fe-based active sites and the corresponding catalytic performance has been rarely investigated. Herein, a series of porous carbon samples with different porosities are obtained by the K2CO3 activation of petroleum pitch under different temperatures. Fe-based active sites and the alkali promoter Na are anchored on the porous carbon to study the effect of carbon support porosity on the physicochemical properties of Fe-based active sites and CO2 hydrogenation performance. Multiple characterizations clarify that the bigger meso/macro-pores in the carbon support are beneficial for the formation of the Fe5C2 crystal phase for C-C bond coupling, therefore boosting the synthesis of C2+ chemicals, especially C2+ alcohols (C2+OH), while the limited micro-pores are unfavorable for C2+ chemicals synthesis owing to the sluggish crystal phase evolution and reactants’ inaccessibility. We wish our work could enrich the horizon for the rational design of highly efficient carbon-supported Fe-based catalysts.

Influence of carbon template and ultrasound irradiation on combustion design of nanostructured calcium manganese oxides used in biodiesel production

Biodiesel, derived from renewable biomass, serves as a sustainable alternative to diesel produced from fossil fuels. This study explores the use of nanostructured MgO/Ca2Mn3O8 catalysts for biodiesel production through transesterification. Ca2Mn3O8 was synthesized as a support catalyst via combustion synthesis, employing carbon templates to control pore size. MgO was impregnated as the active phase using ultrasonic irradiation to enhance particle dispersion. Various characterization techniques, including XRD, FESEM, AFM, TEM, EDX, BET-BJH, and TPD-CO2, were utilized to analyse morphology, porosity, basicity, and active phase dispersion. The use of carbon templates increased pore diameters compared to catalysts without templates, while ultrasonic irradiation improved MgO dispersion. The MgO/Ca2Mn3O8 catalyst with a 10 wt% carbon template and ultrasonic irradiation achieved a maximum conversion rate of 95.5%. Its mesoporous structure, resembling a sponge, facilitated triglyceride diffusion. Stability tests indicated a 90% conversion rate after five reuses. The nanostructured MgO/Ca2Mn3O8 catalyst, with its tailored porosity and structure, demonstrated excellent performance in biodiesel production. Systematically adjusting support porosity and active site dispersion provides a viable approach for designing effective heterogeneous catalysts.

Controlled porosity intelligent aerogel based on chitosan nanofiber, anthocyanins and starch nanoparticles: Preparation, characterization and application in monitoring food spoilage

The aim of this study was to design a food freshness colorimetric aerogel with controlled porosity based on chitosan nanofibers (CHNF), Ixiolirion tataricum anthocyanins (ITA), and starch nanoparticles (SNPs). Two size-controlled SNPs were produced via nanoprecipitation (133.3 nm; SNP-A) and H2SO4 hydrolysis methods (86.2 nm; SNP-B) and were used for controlling the porosity and morphological characteristics of aerogel solid support. According to FE-SEM images, the porosity of smart aerogels improved after SNPs incorporation, and SNP-B was able to decrease the disrupting effect of ITA on 3D porous network of aerogels. The formation of hydrogen bonds between the CHNF and ITA molecules was confirmed by FT-IR analysis and the absence of obvious change in the FT-IR spectra approved the physical entrapment of SNPs. The improvement in the crystallinity and thermal stability of the aerogels after SNPs loading was confirmed by the XRD and TGA tests, respectively. The SNPs loaded aerogels showed color variation from red to green over the pH range of 2–12. In addition, the SNP-B-incorporated aerogel exhibited high sensitivity to ammonia vapor and good color response reversibility. The CHNF/SNP-B/ITA aerogel with the best porosity and sensitivity was used for monitoring food spoilage and could differentiate minced beef into three stages: fresh, medium fresh, and spoiled, facilitating simple observation of freshness-spoilage progression. This research opens a new insight to develop advanced and highly sensitive indicators capable of monitoring freshness/spoilage in protein-based food products.

Local oxygen transport resistance in polymer electrolyte fuel cells: origin, dependencies and mitigation

Next-generation polymer electrolyte fuel cells (PEFCs) require an integral design of the porous structure of electrodes at different scales to improve performance and enlarge durability while reducing cost. One of today’s biggest challenges is the stable, high-performance operation at low Pt loading due to the detrimental effect of the local oxygen transport resistance caused by ionomer around catalyst sites. Hindered local oxygen transport arises from sluggish kinetics at the local reaction environment, that comprises adsorption at (wet) ionomer and Pt interfaces, and diffusivity of gas species in ionomer and water. Diverse factors affect oxygen transport, including operating conditions (relative humidity, temperature, and pressure), ionomer content and morphology, ionomer heterogeneity, porosity of carbon support, catalyst dispersity, and flooding. To attain performance and durability targets, it is essential to maximize the oxygen utilization of the catalyst layer by implementing enhanced membrane electrode assembly architectures. This involves employing advanced catalyst layer preparation techniques, including electrospraying, to generate optimized highly porous morphologies. Furthermore, achieving these targets necessitates the development of new materials with tailored properties, such as high permeability and porous ionomers, among other innovative strategies.

Effect of pore forming agents on the properties and performance of the supported liquid membrane for levulinic acid separation

The porosity of the membrane support plays a crucial role in the performance and efficiency of the supported liquid membrane (SLM) process. The formation of pores and the membrane porosity value can be improved by adding a pore-forming agent in the dope solution during membrane manufacturing. The objective of this study is to investigate the effect of pore-forming additives such as polyethyleneglycol (PEG) 200, PEG 20,000, lithium chloride, Tween-80, and polyvinyl pyrrolidone (PVP 10,000) on the polyethersulfone (PES) membrane properties and their performance in the separation of levulinic acid (LA) using the SLM method. The morphology, contact angle, porosity, and tensile strength of the membrane were evaluated. Among the pore-forming agents tested, PEG 200 emerged as the most effective in inducing a sponge-like structural wall in the PES membrane. It achieved a remarkable porosity level of 87.1%, displaying contact angles of 81.2° and 98° at the top and bottom surfaces, respectively, as well as a high tensile strength of 1032.88 kPa. The membrane achieved the highest extraction of 8.92 g/L LA in the SLM process using a 10 g/L LA aqueous feed solution.

Investigation of Manufacturing Process Related Structure and Performance of the Fuel Cell Electrode Thanks to Small Angle Neutron Scattering

With climate change and fossil fuel sustainability concerns faced globally, proton exchange membrane fuel cell (PEMFC) based electric vehicles have been recognized as a promising alternative. However, large-scale commercialization requires progress in performance, cost and durability, for which the electrode (catalyst layer) is the limiting component. The electrode is composed of nanoparticles of platinum (Pt) catalyst on a carbon (C) support, embedded in a proton conductive polymer (ionomer). It is obtained from a slurry (catalyst ink) after evaporating solvent consisting of a water and alcohol mixture. The structural properties of the slurry, including the ionomer and carbon dispersions, catalyst aggregation and ionomer coverage onto the Pt/C composite strongly influence the performance and durability of the final electrode. Nevertheless, currently little is known of these structures, particularly with regards to the dispersion of the ionomer component onto the surface of porous carbon, despite the fact it is now established that it plays a crucial role in the operation of the fuel cell. The lack of information leaves research and development to be heavily reliant on a trial and error basis. Developing a detailed understanding of the dispersion and its correlation to fuel cell performance is key in advancing the PEMFC electrode.However, the heterogeneous nature of these inks, with only short-range order observed on both micro- and nano- scales, makes them difficult to study by conventional laboratory techniques. Small angle neutron scattering (SANS) has been identified as a suitable method for the study of the electrodes as it is not hindered by the ink opacity as in optical techniques (commonly used to study dispersions) and allows to probe the bulk structures in the 1-100 nm scale relevant for each component. In particular, contrast variation (CV) SANS exhibits a major advantage in studying such complex systems, where scattering signal from multiple components can be deconvoluted by matching the scattering length density of the solvent to that of a desired component. Nevertheless, data on the ink itself is missing and it has only been investigated in a handful of studies by SANS.1-3 Shibayama et al.1 proposed a structural model of Pt/C aggregates coated by an ionomer shell in a water-based ink. Yoshimune et al.2 demonstrated that the amount of Pt on the carbon surface alters the thickness and density of said ionomer layer. Harada et al.3 were able to distinguish adsorbed and deposited ionomer on the composite surface as well as quantize their distribution.Yet although ink composition is known to impact the dispersion greatly, no systematic investigation linking its many variables has been conducted. For example, the ionomer will conform differently in a water/alcohol solvent used commercially in contrast to a water-based one. The porosity of the carbon support will impact distribution of Pt on its surface as well as the degree of ionomer penetration into the support. Additionally, although the fundamental understanding of the ink structure is imperative, it has seldom been further linked to the performance of the electrode itself.Therefore, the aim of this project is to utilize CV-SANS to study the impact of each catalyst ink component on the structure of the dispersion, and their relation to each other, through altering only a single variable at a time. The variables include the components as well as their proportions, such as the carbon concentration or the ionomer to carbon ratio. The performance of the electrode manufactured from said ink compositions will then be evaluated using electrochemical studies. Recently we performed CV-SANS studies on the ink, investigating the extent of ionomer adsorption on the Pt/C composite as a function of both carbon type and presence of Pt in the system. Both carbon supports studied, high surface area carbon with surface nano-pores accessible to the ionomer, and graphitized carbon, which has high internal porosity, yet inaccessible to the ionomer, pose an interest in industrial applications. Indeed, from these preliminary results it is evident platinum plays a significant role in the ink structure, particularly in the case of graphitized carbon (figure 1). The ink system will be quantitatively characterized using a singular value decomposition method already employed in literature to give insight into parameters such as the amount of ionomer adsorbed onto the carbon surface or the structure of the layer. References 1 M. Shibayama, T. Matsunaga, T. Kusano, K. Amemiya, N. Kobayashi and T. Yoshida, J Appl Polym Sci, , DOI:10.1002/app.39842.2 W. Yoshimune and M. Harada, https://doi.org/10.1246/cl.190017, 2019, 48, 487–490.3 M. Harada, S. I. Takata, H. Iwase, S. Kajiya, H. Kadoura and T. Kanaya, ACS Omega, 2021, 6, 15257–15263. Figure 1

Preparation of porous CuS/modified-diatomite composite via a facile in situ loading process for efficient recovery of silver ion from aqueous solution

The study on the recovery of silver ion (Ag+) from silver-containing wastewater is of great significance to heavy metal pollution control and noble metal retrieval. In this work, a porous CuS/modified-diatomite composite was prepared via a pre-modification followed by a mild in situ coating process. A layer of CuS nanosheets was evenly coated onto pre-modified diatomite, and porosity of the diatomite support reserved. Aperture analysis results suggested that the composite possessed a broader porous distribution, higher specific surface area and pore volume than pure CuS. The neosynthetic composite exhibited outstanding adsorption performance for Ag+, according to the Langmuir adsorption isotherm model, with a maximum adsorption capacity of 822.7 mg/g for Ag+, approximately 84 times greater than that of raw diatomite (9.87 mg/g). The highest removal efficiency of the composite for Ag+ reached 99.9 %, and pH values (3–8) and coexisting ions (Na+, K+, Ca2+ and Mg2+) had little influence on the removal of Ag+. Kinetic studies and adsorption product analysis demonstrated that removal of Ag+ on the composite was occupied by chemisorption, arising from that the abundant porosity of diatomite support prompts Ag+ to diffuse onto the composite, and the uniformly coated CuS nanosheets provide abundant active sites for Ag+ chemisorption.

Improving Gas Diffusion in Solid Oxide Cells Through Laser-Ablated Electrode Supports

Improving solid oxide cell power density will enable cheaper commercial-scale SOFCs and SOECs. In Ni-YSZ electrode-supported cells, gas diffusion through the electrode support layer can be a major limitation at high H2 or H2O utilization and high temperature. Conventional methods of improving diffusion through the electrode support include increasing the support porosity and reducing the support thickness, but these can reduce the cell’s structural integrity. Freeze casting1 and 3D printing2 have also been explored to enhance diffusion. Here we explore cells in which the Ni-YSZ supports have macroscopic channels, produced by laser ablation, that reduce the average gas diffusion length.To test the difference in mass transport through patterned and pristine electrode supports, symmetric electrode-supported Ni-YSZ cells are patterned on one side, which enables comparison of the electrochemical performance of two otherwise identical electrodes (Figure 1a). Cells with varying pattern geometry, pore geometries, Ni/YSZ ratios, and Ni-YSZ particle sizes were created to fully understand how the support layer microstructure and macrostructure affects the cell performance. Patterned and pristine cells were tested together at three temperatures (600C, 700C, and 800C) in a 97%H2:3%H2O environment, chosen to produce a clear gas diffusion limitation in H2O electrolysis. j-V sweeps and electrochemical impedance spectroscopy (EIS) were carried out on each cell at each test condition, and the microstructure of patterned and control supports was characterized through SEM imaging.Upon removing the ohmic portion and fitting the j-V data to Equation 1 (see Figure 1), patterned electrodes consistently demonstrated higher limiting current density and lower mass transport losses than the control (Figure 1c-d). Three-point-bend mechanical testing revealed that the mean flexural fracture strengths of pristine cells and patterned cells are 36.0 ± 11.4 MPa and 33.0 ± 8.9 MPa respectively.Combining the equations for limiting current density with diffusion in a system with prismatic channels, we determined the ratio of the limiting current density for a patterned and pristine electrode using Equation 2 (see Figure). For the cell data shown in Figures 1c-1d, we expect an average 33% increase (with a standard deviation of 3.5%) in limiting current density based on microscopy measurements of channel and support layer thicknesses. In 1c, we see that the limiting current density of the patterned electrode is 32% higher than the pristine electrode, which matches our expectation. Furthermore, the Nyquist plot in Figure 1d demonstrates that patterned symmetric cells have similar impedance to pristine cells in the high-frequency regime with less impedance in the low-frequency regime, which is consistent with our expectations that the patterned cells have reduced mass transport losses with similar ohmic and activation losses. These j-V and EIS results suggest that macroscopic support patterning is a promising method for improving performance without compromising structural integrity. Figure 1: a) Ni-YSZ symmetric cell cross-section, laser-patterned with 600 µ m by 600 µ m channels and 200 µ m channel spacing. b) Comparison of the flexural fracture strength for pristine and patterned cells, under 3-point-bend testing. c) IR-free current density-voltage profiles of a patterned Ni-YSZ symmetric cell with a predicted current density improvement of 33%, at 700C in a 97%H2:3%H2O environment. Two distinct j-V responses are observed, based on whether the pristine electrode or the patterned electrode is under a cathodic bias. d) Unbiased potentiostatic EIS (1 MHz - 100 mHz) of a pristine cell versus two patterned cells at 700 C in 97%H2:3%H2O. The cells all have similar Ohmic resistances, but the impedance of the patterned cells is significantly lower in the low-frequency regime, due to the reduction in mass-transport losses. Equation 1: a is a constant, α is the transfer coefficient, j is current density, and jlim,H2O is the limiting current density for H2O diffusion. Equation 2: jlim/jlim,0 is the limiting current density ratio, A is the fraction of the cell surface that is patterned, and tc is the ratio of the channel depth to the patterned electrode thickness.

Kinetic studies of solid foam catalysts for the production of sugar alcohols: Xylitol from biomass resources

Structured catalysts, such as solid foams, represent a very promising technology for continuous and stable production of high-value compounds derived from biomass, traditionally produced with batch and semibatch technologies using suspended catalysts. However, the synthesis of structured catalysts presents additional challenges related to their structure and the generation of porous coatings with suitable properties for dispersing the catalytically active phase on the support.This work was focused on synthesizing a Ru/C solid foam catalyst and investigating its activity in the selective hydrogenation of xylose to xylitol under different operational conditions. The carbon coating, the key step of preparation, was based on the formation and pyrolysis of poly(furfuryl alcohol) in the presence of different amounts of poly(ethylene glycol) (PEG; M = 8 kDa) as a pore former, which enabled tuning the support porosity. Thus, the catalyst prepared with 5 wt% PEG presented a micro-to-mesopores volume ratio of 1, and a good dispersion of Ru nanoparticles, as well as a better stability compared to the catalyst prepared without PEG.The extensive kinetic data collected in this work were mathematically modelled using three different approaches to elucidate the reactant adsorption mode: a non-competitive adsorption model, a non-competitive adsorption model considering the effect of temperature, and a semi-competitive adsorption model. The non-competitive temperature-dependent model displayed better performance in terms of fitting and reliability of the estimated parameters and predicted the adsorption of xylose as an endothermic process. On the other hand, the semi-competitive model gave similar results in terms of fitting and a value for the competitiveness factor of 0.74, which matches the hypothesis that the larger molecules, sugars, can occupy most of the active sites, while some interstitial sites remain accessible for hydrogen adsorption. The modelling results revealed a complex mode of sugar adsorption on the catalyst surface. This modelling concept can be applied to any system in which the molecule sizes are very different.

Fabrication of a Zircon Microfiltration Membrane for Culture Medium Sterilization

Multilayer ceramic membranes to be used for bacteria removal by filtration were prepared from ceramic materials. They consist of a macro-porous carrier, an intermediate layer and a thin separation layer at the top. Tubular and flat disc supports were prepared from silica sand and calcite (natural raw materials), using extrusion and uniaxial pressing methods, respectively. Making use of the slip casting technique, the silica sand intermediate layer and the zircon top-layer were deposited on the supports, in this order. The particle size and the sintering temperature for each layer were optimized to achieve a suitable pore size for the deposition of the next layer. Morphology, microstructures, pore characteristics, strength and permeability were also studied. Filtration tests were conducted to optimize the permeation performance of the membrane. Experimental results show that the total porosity and average pore size of the porous ceramic supports sintered at different temperatures within the range (1150-1300 °C), and lie in the ranges of 44-52% and 5-30 μm, respectively. For the ZrSiO4 top-layer, after firing at 1190 °C, a typical average pore size of about 0.3 μm and a thickness of about 70 μm were measured, while water permeability is estimated to a value of 440 lh-1m-2bar-1. Finally, the optimized membranes were tested in the sterilization of a culture medium. Filtration results show the efficiency of the zircon-deposited membranes for bacteria removal; indeed, the growth medium was found to be free of all microorganisms.

Development of functionally graded anode supports for microtubular solid oxide fuel cells by tape casting and isostatic pressing

This paper suggests an alternative method to manufacture functionally graded anode supports for microtubular solid oxide fuel cells by employing tape casting and isostatic pressing for the first time in the literature. In this regard, six different anode support strips with various pore former contents are produced by tape casting. Besides the anode supports made from uniform tapes, three-layered anode supports composed of various combination of these tapes are also fabricated by wrapping the corresponding tape(s) of the same total length on a metallic rod followed by isostatic pressing. Microtubular cells are then built on these anode supports by dip coating the other layers and evaluated by microstructural investigations and electrochemical performance tests performed under the same conditions. Porosity measurements of the homogeneous anode supports are also carried out. Microstructural examinations reveal that not only the homogeneous anode supports but porosity graded anode supports can be also successfully manufactured by the suggested method. Electrochemical tests indicate that the performance of the cells with a uniform anode support tends to increase with the anode support porosity up to ∼26% porosity then shows a decreasing trend. The highest maximum performance of 0.645 Wcm−2 at 800 °C under 0.3 NLmin−1 hydrogen and stationary air, on the other hand, is obtained from the cell with a porosity graded anode support.

Fragmentation-Oriented Design of Olefin Polymerization Catalysts: Support Porosity

The development of catalysts for the production of polyethylene and polypropylene is ordinarily accomplished on a trial-and-error experimentation program. From the point-of-view of the fragmentation performance, support porosity is the key property affecting the mechanical support resistance, and, therefore, it determines the fragmentation process during the early moments of polymerization. The design of the support porosity can be more accurately determined by applying the theoretical knowledge acquired from previous research, but this is not consolidated for catalyst design. This article reports a methodology to optimize the support porosity using a simple fundamental model of the fragmentation process. Using this approach, the design of fragmentation-oriented supports can be achieved for polymerization reactors.

Synthesis of small-sized intermetallic PtCo fuel cell catalysts by promoting inner surface utilization of carbon supports

The utilization of the internal porosity of the carbon support is a key factor for small-sized PtCo IMCs.

Fabrication of NiO/YSZ-Based Anodes for Solid Oxide Fuel Cells by Hybrid 3D Inkjet Printing and Laser Treatment

An anode for solid oxide fuel cells (SOFCs) was fabricated using 3D inkjet printing and layer-by-layer laser treatment of compositions based on the NiO/YSZ system followed by thermal sintering. The samples were characterized by scanning electron microscopy and X-ray phase analysis. The study of the morphology of the as-prepared samples revealed the presence of both interlayer macroporosity and intralayer microporosity, which depends on the laser exposure during laser treatment. The use of graphite directly added to the printing composition as the pore former increased the intralayer porosity. The morphology and size of the pores were shown to be similar to those of the pore former. The microstructure and porosity of the anode support can be controlled by varying the laser exposure values and the graphite content of the ceramic composite, which in turn opens up great prospects for using these paste compositions and printing techniques for the manufacture of SOFC anode supports.

SAPO-containing alumina CoMoNi-catalysts for hydrotreatment of heavy oil: Pore hierarchy as a key parameter for catalyst stabilization

This paper is devoted to the study of activity and lifetime of CoMoNi-catalyst containing one-dimensional SAPOs in heavy oil hydrotreatment. A special attention is paid to porous structure of SAPOs and catalyst supports. Porosity of supports is designed by two hard templates. Pore structure containing narrow and wide mesopores and macropores is referred as high-resolved pore hierarchy. In turn, pore structure containing narrow mesopores and macropores is referred as bimodal pore hierarchy. Zeolite-like SAPOs also differ in their own pore hierarchy and acidity. Catalysts have been characterized with XRD, nitrogen adsorption-desorption, Hg-intrusion, Raman and XP spectroscopies and SEM. Catalytic tests for 100 h for each catalysts have been shown that support pore hierarchy should be designed depending on pore hierarchy and morphology of zeolite-like material. In general, high-resolved pore hierarchy improves mass transfer, makes CoMoNi sites accessible and creates gradual pore channel expansion and, as a result, prevents deactivation of zeolite-like containing catalysts.

Micro-patterned cellulose triacetate membranes for forward osmosis: Synthesis, performance and anti-fouling behavior

Most cellulose triacetate (CTA)-based studies for forward osmosis (FO) have greatly focused on achieving asymmetric membranes with a highly porous sublayer along with a dense selective layer. Such membranes can achieve better fluxes due to improved mass transfer and reduced internal concentration polarization. In this work, patterning of the CTA-membranes via modification of the conventional non-solvent induced phase inversion is explored as an alternative route to increase FO water flux without reducing salt selectivity. The modified way of applying the non-solvent in this method increased the membrane bulk porosity from ~17 % to ~50 %. Such high porosity and reduced tortuosity of the patterned membrane can reduce the internal concentration polarization by back-transport and reduced accumulation of salt and other solutes in the porous support. During FO, the patterned CTA membrane showed a water flux of 30 L m−2 h−1 and reverse salt flux of 25 g m−2 h−1, thanks to the increased effective membrane area, low water transport resistance, and high porosity of the membrane support. The patterned CTA-membranes may have potential in FO for applications with larger draw solutes due to the slightly larger pores on the membrane surface following the non-solvent spraying. Alternatively, some phase inversion parameters can still be further tuned to lower the salt passage.

The Synergetic Effect of Support‐oxygen Groups and Pt Particle Size in the Oxidation of α‐D‐glucose: A Proximity Effect in Adsorption

AbstractThe influence of the support‐oxygen groups and Pt particle size on the catalytic performance of Pt/AC for the aerobic oxidation of α‐D‐glucose to gluconic acid (glycolate) was studied. Surface‐oxygen groups were introduced by treating the activated carbon support with diluted HNO3 without significantly affecting the support porosity. The platinum particle size could be decreased on both the treated and untreated support by adding an additional calcination step to the synthesis. The presence of oxygen‐containing groups is shown to be highly beneficial (∼4 fold increase in the turnover frequency) only for the smallest Pt particle size (1.8–2.5 nm, determined by TEM). For the catalyst with the larger Pt size (3.4–3.6 nm), the presence of additional oxygen‐contacting groups does not significantly enhance the activity. Since the size of the smaller Pt particles is close to the product/substrate molecular diameter (glucose/gluconic acid, ∼0.9 nm) the observed effect can be attributed to the effective repulsion by the negatively charged oxygen groups in close proximity to the glycolate reaction product. The increase in activity originates from the resulting enhanced desorption of glycolate by alleviating the product inhibition presence due to the strong interaction of glycolate with Pt.