N2 Sorption Analysis Research Articles

A Facile Method to Incorporate Di-Dopant Elements (F and Sb) into Crystalline Mesoporous Tin Dioxide Nano Powder at Ambient Temperature and Pressure.

A simple two step synthetic method for di-doped crystalline mesoporous tin dioxide powder containing antimony and fluoride at ambient pressure and temperature has been developed. This approach produced materials with high surface areas and improved electrical and optoelectrical conductance. The two dopant elements; antimony and fluoride were introduced to tin dioxide by two approaches. Both approaches produced mesoporous tin dioxide with antimony and fluoride that are integrated in the framework. The structures of these materials are analyzed by powder X-ray diffraction, N2 sorption analysis, transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The conductance of the materials improved by factor of 13-34 compared to undoped mesoporous tin dioxide. The effect of the di-doped elements on structure, conductance and optoelectronic properties of these materials are discussed in this paper.

Synthesis and Characterization of Mesoporous Materials Functionalized with Phosphinic Acid Ligand and Their Capability to Remove Cd(II).

This article presents a study of cadmium removal from nitrate medium using adsorption in calcined mesoporous silica (MCM-C), mesoporous silica doped (MCM_DIOPA), and calcined and impregnated mesoporous silica (MCM@DIOPA), with diisooctylphosphinic acid (DIOPA). The sorbents were synthesized via a sol-gel method. Several characterization techniques, such as XRD, FTIR spectroscopy, N2 sorption and elemental analysis, have been used to determine the main structural, textural, and chemical properties of prepared sorbents. Batch adsorption and kinetics tests were carried out, where the influence of pH and contact time of the sorbents and their role in cation removal were studied. Experimental results show poor sorption efficiencies with MCM-C and MCM_DIOPA at pH 5.85. At the same pH, better cadmium extraction was attained by MCM@DIOPA and was achieved within 30 min. The pseudo-second-order model is the most appropriate model to describe the elimination mechanism of Cd(II) ions. The Langmuir equation was used to model the sorption isotherm and the maximum sorption capacity of Cd(II) is 22.16 mg/g (200 mmol/kg). The complex type of the probable extracted species isCdL2-HL.

Hierarchical Bifunctional NiO Electrocatalyst: Highly Porous Structure Boosting the Water Splitting Activity.

The development of an efficient, low-cost and earth-abundant electrocatalyst for water splitting is crucial for the production of sustainable hydrogen energy. However their practical applications are largely restricted by their limited synthesis methods, large overpotential and low surface area. Hierarchical materials with a highly porous three-dimensional nanostructure have garnered significant attention due to their exceptional electrocatalytic properties. These hierarchical porous frameworks enable the fast electron transfer, rapid mass transport, and high density of unsaturated metal sites and maximize product selectivity. Here the process involved obtaining monodispersed microrod-shaped Ni(OH)2 through a hydrothermal reaction, followed by a heat treatment to convert it into hierarchical microrod-shaped NiO materials. N2 sorption analysis revealed that the BET surface area increased from 9 to 89 m2/g as a result of the heat treatment. The hierarchical microrod-shaped NiO materials demonstrated outstanding bifunctional electrocatalytic water splitting capabilities, excelling in both HER and OER in basic solution. Overpotential of 347 mV is achieved at 10 mA/cm2 for OER activity, with a Tafel slope of 77 mV/dec. Similarly, overpotential of 488 mV is achieved at 10 mA/cm2 for HER activity, with a Tafel slope of 62 mV/dec.

Photocatalytic reduction of nitroarene derivatives by impressive visible-light active Co3O4-QDs/Mn3O4 nanocomposite

A visible light active Co3O4-quantum dots (QDs)/Mn3O4 nanocomposite was successfully synthesized by a straightforward precipitation approach. Notably, the formation of Mn3O4 nanosheets in composite structure was evidenced by different physicochemical techniques especially transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and N2 sorption analyses, which indicated the uniform distribution of Co3O4-QDs with small size of around 5 nm on the surface of Mn3O4 nanosheets along with the enhancement of specific surface area for final composite. Also, the persistence of Co3O4-QDs during nanocomposite synthesis was analyzed by X-ray diffraction (XRD), FT-IR and TEM techniques. The diffuse reflectance UV–Vis and electrochemical impedance spectroscopies revealed the reduction of band gap energy and enhanced charge separation efficiency for Co3O4-QDs/Mn3O4 nanocomposite, respectively, which consequently led to improved photocatalytic response in comparison with bare Co3O4-QDs and Mn3O4 nanosheets. The as-prepared nanocomposite exhibited excellent photocatalytic activity in the reduction of a wide range of substituted nitroarenes with the yields of higher than 80 % relative to the corresponding arylamines, using N2H4·H2O as the hydrogen source and ethanol as green solvent at 25 °C and ambient pressure under visible light illumination. The synergistic effect could improve the production of active hydrogen atoms, therefore, the reasons for this transformation over the prepared nanocomposite under benign conditions are fully discussed. Furthermore, the nanocomposite could be easily recycled without decay in photocatalytic activity for at least five successive cycles.

MIL-101(Cr) supported Pt and Au-Pt composites as active catalysts for the selective hydrogenation of nitrobenzene under mild reaction conditions

In this study, we report the successful synthesis of monometallic Pt(2 wt.%)/MIL-101(Cr) and bimetallic Au(1 wt.%)-Pt(1 wt.%)/MIL-101(Cr) catalysts with low dimension MeNPs by the double-solvent (DS) method. The catalysts were characterized by powder X-ray diffraction (PXRD), N2 sorption analysis (BET), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and transmission electron microscopy (TEM). The characterization results demonstrated the presence of well-dispersed Pt and Au-Pt nanoparticles (2.9 and 2.7 nm, respectively), located mainly inside the pores of MIL-101(Cr). The stronger interaction of Au-Pt NPs with the support compared to Pt NPs was demonstrated by H2-TPR and XPS, which proved the existence of charge exchange between Pt NPs and Cr from MIL-101 in the case of Au(1 wt%)-Pt(1 wt%)/MIL-101(Cr), but not in the case of Pt(2 wt%)/MIL-101(Cr). The composite materials were tested in the catalytic selective hydrogenation of nitrobenzene to aniline in liquid phase under mild conditions (low temperature, low hydrogen pressure), and in the presence of a biomass-derived non-toxic solvent (ethanol). The bimetallic Au(1 wt%)-Pt(1 wt%)/MIL-101(Cr) catalyst showed superior catalytic activity as compared to the monometallic Pt(2 wt%)/MIL-101(Cr) catalyst. This is due to the synergetic effect between the two metals as demonstrated by the projected density of states studies.

The catalytic performance of γ-Al2O3/red clay as a highly active, selective, and stable catalyst for methanol dehydration to dimethyl ether at competitive low reaction temperature

This study aims to a more environment eco-friendly approach for producing dimethyl ether (DME), as an alternative fuel, through the dehydration of methanol. The method involves utilizing Egyptian natural red clay (ERC) that has been modified with various percentages of γ-Al2O3 (ranging from 3 to 30 wt%) as catalysts. The most active catalyst (10 % γ-Al2O3/ERC) was then modified with varying HCl percentages (3–7 wt%). The synthesized catalysts properties were examined by various techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2-sorption analysis, and transmission electron microscopy (TEM). The surface acidity of the catalysts was assessed using two methods: dehydration of isopropyl alcohol and chemisorption of pyridine and 2,6-dimethyl pyridine. The results of the catalytic activity study reflected that the treatment of ERC by HCl and γ-Al2O3 improved its activity toward DME production. Specifically, the 5 % HCl/10 % γ-Al2O3/ERC catalyst displayed outstanding activity, achieving conversion value of 90 % with 100 % selectivity to DME at 200 °C. Furthermore, this catalyst demonstrated long-term stability, as it maintained its performance over one week without deactivation. Acidity, and the textural characteristics were identified as the key factors contributing to the remarkable improvement in catalytic activity.

Novel monolithic catalysts for the hydrotreating of oleic acid

Alumina-supported palladium and molybdenum carbide monolithic catalysts were tested in the hydrodeoxygenation of oleic acid. Anodized aluminum monoliths were used as the substrate of the structured catalysts. The Pd catalyst was synthetized by wet impregnation, and the Mo2C sample was prepared in situ using the temperature-programmed carburization methodology. The monolithic catalysts were characterized by X-ray diffraction, N2 sorption analysis, CO chemisorption and scanning electron microscopy. The catalytic tests were carried out in a continuous tubular reactor at temperatures between 553 and 633 K, with a hydrogen pressure of 30 atm. Both catalysts showed to be active, reaching a conversion of oleic acid higher than 92% at 633 K. The deoxygenation reactions using the Mo2C catalyst were suppressed, favoring the saturation of carbon-carbon double bonds and the stearic acid formation. On the other hand, oleic acid hydrodeoxygenation was promoted when using the palladium-based catalyst, forming undecane and tridecane alkanes.

Enhanced Biodiesel Production from Waste Cooking Oil Using Potash-Enriched Natural Base Catalyst

The transesterification reaction of waste cooking oil with methanol using a sugar apple peel ash catalyst has been reported. Under optimized conditions, the reaction of the oil with methanol in a molar ratio of 1:10, in the presence of a catalyst (2 g) at 60 °C temperature offered a 94.5% yield of biodiesel within 120 min. The heterogeneous catalyst was developed via a straightforward calcination process using fruit processing industry waste peels of sugar apples. The characterization of the catalyst by FTIR, EDS, SEM, XRD, N2 sorption, and XRF analysis revealed a higher concentration of potassium species which is possibly responsible for the promotion of the transesterification reaction more efficiently. This approach offers cost competitiveness, reusability of the catalyst, simplicity of operation, and high biodiesel yields. This study underscores the potential of utilizing waste materials for sustainable biodiesel production, contributing to environmental preservation and economic viability.

Tuning of the acid sites in the zeolite-alumina composite Ni catalysts and their impact on the palm oil hydrodeoxygenation reaction

The hydrodeoxygenation (HDO) of bio-oil is one of the potential approaches to produce green diesel. However, HDO catalyst requires the development of bifunctionality which translates to the simultaneous presence of acidic and metal sites for desired catalytic activity and selectivity. Zeolites and their composites are attractive candidates for the conversion of biomass to fuels. In the present work, a series of Ni-incorporated Al2O3-zeolite beta bifunctional composite catalysts with distinct Al2O3 (25–75 wt%) and Ni contents (5–15 wt%) were synthesized via a facile one-pot method directly from nickel acetate, nano-boehmite (γ-AlO(OH)) and the NH4+ form of beta zeolite (NH4+-BZ). The nano-boehmite particles, due to the positive charges on their surface, electrostatically attract negatively charged beta zeolite crystals, which leads to the assembly of a hierarchical pore structure upon calcination. Interestingly, the composite catalysts synthesized were quite homogeneous with uniform dispersion of Ni particles. All composite catalysts were thoroughly characterized using XRD, SEM-EDX, SEM-mapping, HR-TEM, H2-TPR, H2-TPD, NH3-TPD, XPS, 31P MAS NMR, 27Al MAS NMR and N2 sorption analysis. The synthesized composite catalysts with distinct Al2O3 contents showed diverse textural properties, distinct nature of acid sites and improved performance in hydrodeoxygenation of palm oil. Particularly, the Ni/BZ-Al50 (with BZ:Al2O3 = 50:50) composite catalyst significantly enhanced the conversion of palm oil (up to 90%) and yield of n-C15-C18 hydrocarbons (up to 69%) at moderate temperature of 375 °C as compared to 10Ni/BZ catalyst (Conv. = 75%, yield of n-C15-C18 = 52%). The higher catalytic performance realized with composite catalysts can be ascribed to its hierarchical pore structure, moderate acidity (chemisorption studies), tuned acid sites nature (solid state NMR) and homogeneous distribution of active Ni sites (H2 chemisorption) which helps to improve product selectivity by minimizing side reactions. The time-on-stream (TOS) experiments were carried out up to 20 h which clearly showed that composite catalysts are more stable suggesting the lower amount of coke deposition (TPO studies) and suppression of metal sintering.

Ag‐Nanocatalysts Based on Porous Organic Polymers in Chemical Fixation of CO2 for the N‐Methylation and N‐Formylation of Amines

AbstractChemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver‐loaded porous organic polymer catalysts for the exclusive N‐formylation and N‐methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP‐based materials Ag@TTP‐1 and Ag@PAN‐T are utilized as low‐cost catalysts for both the N‐methylation and N‐formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP‐1 demonstrated superior catalytic efficiency compared to Ag@PAN‐T in the N‐methylation and N‐formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above‐mentioned catalysts (Ag@TTP‐1 and Ag@PAN‐T) are characterized through powder XRD, FT IR spectroscopy, FE‐SEM, TEM, thermogravimetric techniques, N2 sorption and XPS analysis. Ag‐nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction.

Understanding and Controlling Molecular Compositions and Properties in Mixed-Linker Porphyrin Metal-Organic Frameworks.

Porphyrin-based metal-organic frameworks (MOFs) are attractive materials for photo- and thermally activated catalysis due to their unique structural features related to the porphyrin moiety, guest-accessible porosity, and high chemical tunability. In this study, we report the synthetic incorporation of nonplanar β-ethyl-functionalized porphyrin linkers into the framework structure of PCN-222, obtaining a solid-solution series of materials with different modified linker contents. Comprehensive analysis by a combination of characterization techniques, such as NMR, UV-vis and IR spectroscopy, powder X-ray diffraction, and N2 sorption analysis, allows for the confirmation of linker incorporation. A detailed structural analysis of intrinsic material properties, such as the thermal response of the different materials, underlines the complexity of synthesizing and understanding such materials. This study presents a blueprint for synthesizing and analyzing porphyrin-based mixed-linker MOF systems and highlights the hurdles of characterizing such materials.

Preparation of mesoporous silica and organosilica nanostructures functionalized with C2‐symmetric diol and their catalytic performance in diethylzinc addition to aromatic aldehydes

In this study, heterogenization of C2‐symmetric (1R,2R)‐1,2‐bis(4‐(3‐(triethoxysilyl)propyl)phenyl)ethane‐1,2‐diol compound and investigation of the effect of structural arrangements of nanocatalysts on catalytic activity were carried out. For this, bissilyl derivative of (1R,2R)‐1,2‐bis(4′‐bromophenyl)‐ethane‐1,2‐diol, named as C2‐BSi, was obtained by 2‐step synthesis. Then, mesoporous silica nanocatalysts C2‐BSi@SBA‐15 and C2‐BSi@MCM‐41 were synthesized by grafting of C2‐BSi onto SBA‐15 and MCM‐41, whereas mesoporous organosilica nanocatalysts C2‐BSi‐MON‐(a) and C2‐BSi‐MON‐(b) were synthesized by co‐condenzation of C2‐BSi and tetraethyl orthosilicate (TEOS). Structure determinations of synthesized organic substances were performed by 1H, 13C NMR, Fourier transform infrared (FT‐IR), polarimeter, and mass analysis, whereas the structural properties of heterogeneous catalysts C2‐BSi@SBA‐15, C2‐BSi@MCM‐41, C2‐BSi‐MON‐(a), and C2‐BSi‐MON‐(b) were determined by FT‐IR, X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and N2 sorption analyses. The catalytic activities of novel heterogenous materials were tested in the reaction of Ti‐promoted enantioselective diethylzinc addition to aromatic aldehydes. The effects of the structural arrangements of the prepared heterogeneous catalyst on the catalytic activity were examined and compared with the catalytic activity values of their homogeneous analog. According to the results, all catalysts catalyzed the reactions and afforded the corresponding products with high conversion (82–99%) but low enantioselectivity (rac‐7% ee). The conversion values in heterogeneous catalysis were higher than those in homogeneous catalysis. C2‐BSi‐MON‐(a) with the largest pore width stood out as the most effective catalyst (99% conversion, 7% ee). The findings from the catalytic activity experiments confirmed that the structural arrangement of the nanocatalysts has an effect on the performance of the catalysts in the reaction.

Exploring metal carbamates as precursors for the synthesis of metal-organic frameworks.

In the synthesis of metal-organic frameworks (MOFs), the choice of the metal precursor plays a key role because of the influence that it can exert on the crystallization kinetics. The present work explores the use of metal-carbamato complexes for the synthesis of benchmark MOFs, namely HKUST-1 and UiO-66. Cu2(O2CNEt2)4·2NHEt2 and Zr(O2CNEt2)4, prepared using straightforward CO2 fixation reactions starting from the corresponding metal chlorides and diethylamine, were employed as metal precursors for MOF formation. The synthesis conditions, including the solvent, temperature, and ligand protonation degree, were systematically investigated, revealing metal carbamates as highly reactive precursors due to their prompt release of CO2 and amine upon reaction with protic species, i.e., the polycarboxylic linkers. This property of metal carbamates allowed us to identify room temperature protocols to achieve MOFs with comparable properties to those obtained using traditional metal precursors. Subsequent optimization of the reaction conditions led to the design of a one-pot synthetic strategy for HKUST-1, starting directly from copper(II) chloride and diethylamine under a CO2 atmosphere. The MOFs were characterized using various techniques, including powder X-ray diffraction, N2 sorption analysis, 1H nuclear magnetic resonance spectroscopy, and CHN elemental analysis, and compared to reference samples prepared according to literature procedures.

Fabrication and characterization of magnetic mesoporous nanoparticles for efficient determination and magnetic separation of sulfonamides in food samples.

A magnetic, mesoporous core/shell structured Fe3O4@SiO2@mSiO2 nanocomposite was synthesized and employed as a magnetic solid phase extraction (MSPE) sorbent for the determination of trace sulfonamides (SAs) in food samples. The synthesized nanocomposite was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, X-ray diffraction, N2 sorption analysis and vibrating sample magnetometry. The results showed that Fe3O4@SiO2@mSiO2 possessed a mesoporous structure with a large surface area. Batch experiments were carried out to investigate the adsorption ability for SAs. Fe3O4@SiO2@mSiO2 showed fast kinetics and high adsorption capacity, and the pseudo-second-order model and Langmuir adsorption isotherm are well fitted with the experimental data, indicating that chemical adsorption might be the rate-limiting step. Moreover, the high adsorption capacity can be maintained for at least 8 runs, indicating excellent stability and reusability. The proposed method exhibited good linearity in the range of 0.2-500 μg L-1, the R2 values of all the analytes were greater than 0.99 and the LODs were all lower than 0.2 μg L-1. Furthermore, real food samples were successfully analyzed with Fe3O4@SiO2@mSiO2 and high recoveries varying from 89.7% and 110.6% were obtained with low relative standard deviations ranging from 1.78% to 6.91%. The Fe3O4@SiO2@mSiO2 magnetic nanocomposite is a promising sorbent for the efficient extraction of SAs from complex food samples.

Removal of metronidazole from simulated wastewater using Fe/C catalyst with a combination of heterogenous Fenton and ozonation

This study examined roles of iron oxide/porous carbon material (Fe/C) for removing metronidazole in simulated wastewater by adsorption and then followed by a degradation using advanced oxidation process (H2O2, O3 and combination of H2O2/O3). Fe/C was produced by an impregnation of iron oxide precursors during resorcinol-formaldehyde synthesis followed by pyrolysis at 800 °C. For comparison, blank carbon (without iron loading) was also synthesized. The properties of porous carbon were investigated by SEM-EDX and N2-sorption analyzer. Blank carbon and Fe/C featured the specific surface area of 755 m2g-1 and 394 m2g-1, respectively. The loading of iron oxide altered the pore structures of material. The adsorption isotherm data were followed by the Langmuir isotherm model with metronidazole uptake up to 46.07 mg g-1 and 39.97 mg g-1 at 30oC by Fe/C and blank carbon. The degradation study was then carried out with catalyst dosage of 0.1 g/100 mL solution and 120 min reaction time at 30 oC. It is noticeably that, the degradation of metronidazole was better when a combination of H2O2/O3 was employed, compared with an individual of H2O2 or O3. Regarding the stability, Fe/C maintained its high activity upon four consecutive runs.

Crystalline Mesoporous F-Doped Tin Dioxide Nanomaterial Successfully Prepared via a One Pot Synthesis at Room Temperature and Ambient Pressure.

We report the successful one pot synthesis of crystalline mesoporous tin dioxide powder doped with fluoride at ambient pressure and temperature. This material possesses a high surface area, narrow pore size distribution, small average crystallite sizes, and good opto-electrical properties. The existence of fluorine increased the opto-electronic activity of tin dioxide by 20 times, and conductivity by 100 times compared with pristine tin dioxide prepared via the same method. The conductivity of SnO2 in air at 25 °C is 5 × 10-5 S/m, whereas that of F-SnO2 is 4.8 × 10-3 S/m. The structures of these materials were characterized with powder X-ray diffraction, N2 sorption analysis, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV-visible spectroscopy. Fluorine occupies the framework of tin dioxide by replacing some of the oxygen atoms. The structure, conductance, and optical properties of these materials are discussed in this paper.

Magnesium‐Ion Battery Anode from Polymer‐Derived SiOC Nanobeads

AbstractTin‐containing silicon oxycarbide (SiOC/Sn) nanobeads are synthesized with different carbon/tin content and tested as electrodes for magnesium‐ion batteries. The synthesized ceramics are characterized by thermogravimetric‐mass spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction (XRD), Raman spectroscopy, N2 sorption analysis, scanning electron microscope, energy‐dispersive X‐ray, and elemental analysis. Galvanostatic cycling tests, rate performance tests, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) tests, and ex situ XRD measurements are conducted. Results of battery performance tests present a high capacity of 198.2 mAh g−1 after the first discharging and a reversible capacity of 144.5 mAh g−1 after 100 cycles at 500 mA g−1. Excellent rate performance efficiency of 85.2% is achieved. Battery performances in this research are influenced by surface area, and tin contentof the SiOC/Sn nanobeads. EIS, CV tests, and ex situ XRD measurements reveal that higher surface area contributes to higher capacity by providing more accessible Mg2+ ion storage sites and higher rate capability by improving the diffusion process. Higher Sn content increases battery capacity through reversible Mg‐Mg2Sn‐Mg alloying/dealloying process and improves the rate performances by increasing electrical conductivity. Besides, SiOC advances cycling stability by preventing electrode collapse and enhances the capacity due to higher surface capacitive effects.

(Digital Presentation) Synthesis of Proton Exchange Membrane Fuel Cell Catalyst and Optimization of Membrane Electrode Assembly Preparation Parameters

Reducing platinum content in proton exchange membrane fuel cells (PEMFCs) is one of the most essential development directions to secure the economic viability of PEMFC. Efforts are being made to synthesise new, more active catalysts and to optimise PEMFC assembly parameters. (1–4)The study aimed to synthesise 60 wt% Pt/C catalyst and optimise catalyst loading on the electrodes, gasket thickness and coating strategy.The catalyst was synthesised by depositing Pt nanoparticles on carbon black (Ketjenblack EC-300J) using ethylene glycol as a reducing agent and solvent (5–7). The studied catalyst was characterised by thermogravimetric analysis, X-ray diffraction and N2 sorption analysis. The synthesized catalyst material contained approximately 60 wt% of Pt, and the average platinum crystallite size was under 3 nm. The catalyst had a micro-mesoporous structure with a specific surface area of 320 m2 g−1.For electrochemical characterisation, the measurements were performed in H2/air PEMFC. Using an ultrasonic coating system, the catalyst was deposited on the Nafion membrane or gas diffusion layer. A suitable gasket thickness was found using electrochemical measurements. The catalyst loading was varied on the anode between 0.05 and 0.50 mg cm−2 and on the cathode between 0.40 and 1.00 mg cm−2, leaving the catalyst loading constant on the non-variable electrode. Electrodes thickness depended linearly on the catalyst loading. The results showed that electrochemically active surface area does not depend on catalyst loading. Varying catalyst loading on the anode did not show a decrease in electrochemical activity; thus, the anode catalyst loading could be reduced to 0.05 mg cm−2. However, the electrochemical activity decreased at low cathode catalyst loadings. It was found that the cathode catalyst loading can be reduced to 0.60 mg cm−2.Under optimised conditions, the electrochemical activity of the investigated material was excellent. The PEMFC current density was 0.81 A cm−2 at 670 mV, the maximum achieved power density 0.80 W cm−2 and the electrochemically active surface area 56 mPt 2 gPt −1. Acknowledgements This work was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011) and the Estonian Research Agency project (personal research support group grant project No. PRG676). References R. Alink, R. Singh, P. Schneider, K. Christmann, J. Schall, R. Keding, and N. Zamel, Molecules, 25, E1523 (2020).Á. Kriston, T. Xie, D. Gamliel, P. Ganesan, and B. N. Popov, Journal of Power Sources, 243, 958 (2013).J. Lee, C. Seol, J. Kim, S. Jang, and S. M. Kim, Energy Technol., 9, 2100113 (2021).H. A. Gasteiger, J. E. Panels, and S. G. Yan, Journal of Power Sources, 127, 162 (2004).Y. Shao, S. Zhang, R. Kou, X. Wang, C. Wang, S. Dai, V. Viswanathan, J. Liu, Y. Wang, and Y. Lin, Journal of Power Sources, 195, 1805 (2010).W. Li, C. Liang, W. Zhou, J. Qiu, Zhou, G. Sun, and Q. Xin, J. Phys. Chem. B, 107, 6292 (2003).R. Kou, Y. Shao, D. Mei, Z. Nie, D. Wang, C. Wang, V. V. Viswanathan, S. Park, I. A. Aksay, Y. Lin, Y. Wang, and J. Liu, J. Am. Chem. Soc., 133, 2541 (2011).

(Digital Presentation) The Utilization of Platinum Catalysts Deposited on Carbon Support Synthesized from Coffee Grounds in a Polymer Electrolyte Membrane Fuel Cell

Exploring alternative sources for platinum catalyst carbon support material is vital for the further development of polymer electrolyte membrane fuel cells (PEMFC).1 The support material and the method of depositing Pt nanoparticles are crucial for defining the catalytic properties of the catalyst. In this study, carbon support material, derived from coffee grounds was used in the preparation of Pt catalysts for PEMFC application. The carbon material was synthesized using ZnCl2 activated pyrolysis method2 and the Pt nanoparticles were deposited onto carbon support by two methods: using ethylene glycol3 or hydrogen4 as a reducing agent.The physical properties of the support material, as well as catalysts were analysed through thermogravimetric analysis (TGA), dynamic light scattering, X-ray diffraction (XRD), N2 sorption analysis and high-resolution scanning electron microscopy (HR-SEM) methods. The electrochemical activity, as well as the electrochemically active surface area (ECSA) of the catalysts were determined in a completed PEMFC. The properties and performance of catalysts synthesised were compared with the catalyst which was deposited onto commercial carbon (Ketjenblack, EC-300J).TGA displayed that carbon derived from coffee grounds contained 6.9 % of impurities by mass in the form of metal oxides and that the coffee carbon Pt catalyst contained 60 wt% of Pt. The Pt crystallite size was determined through XRD and it was 1.4 nm. HR-SEM analysis displayed that the average particle size of Pt nanoparticles on the coffee carbon catalyst was 4.7±2.5 nm. Results from N2 sorption analysis showed that all materials were micro-mesoporous, with coffee ground carbon having a specific surface area of 590 m2 g-1. The coffee carbon Pt catalyst produced smaller results of 370 m2 g-1 compared to the carbon support, due to the Pt nanoparticles depositing in the micropores, however still had a larger specific surface area than the commercial carbon catalyst with a specific surface area of 300 m2 g-1.Catalysts deposited on coffee ground carbon produced comparable electrochemical results to catalysts deposited on commercially available carbon. The coffee carbon catalyst produced a higher ECSA of 64 mPt 2 gPt -1, compared to the commercial carbon catalyst with an ECSA of 51 mPt 2 gPt -1. The current density of the Pt catalyst deposited onto coffee carbon was 0.68 A cm-2 at 670 mV, whilst in the same conditions commercial carbon peaked at 0.70 A cm-2. Both coffee and commercial carbon Pt catalysts produced similar power density maximums with the coffee Pt catalyst producing 0.56 W cm-2 and the commercial Pt catalyst producing 0.60 W cm-2.Physical and electrochemical characterizations displayed that higher ECSA values were strongly correlated to smaller Pt crystallite size. Other techniques to increase fuel cell performance were also experimented with, such as covering the gas diffusion layer with catalyst instead of Nafion membrane and adding additional Nafion layers, with both methods producing promising results.This study displays that there is a lot of potential in improving the catalytic performance of Pt catalysts by depositing on support materials derived from alternative sources. The methods of boosting PEMFC performance could be further investigated for catalysts deposited on different carbon supports. Acknowledgements This work was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011), Personal Research Grant PRG676 and by private limited company AuVe Tech LLTKT20148 “Production of Polymer Electrolyte Membrane Fuel Cells”. The SEM measurements were conducted using the NAMUR+ core facility funded by the Estonian Research Council (TT 13). References S. Shahgaldi and J. Hamelin, Carbon, 94, 705-728 (2015). M. Härmas, PhD thesis, University of Tartu, Tartu, Estonia (2020). Y. Shao, S. Zhang, R. Kou, X. Wang, C. Wang, S. Dai, V. Viswanathan, J. Liu, Y. Wang, Y. Lin, J. Power Sources 195, 1805-1811 (2010). Y. Zheng, Z. Dou, Y. Fang, M. Li, X. Wu, J. Zeng, Z. Hou, S. Liao, J. Power Sources, 306, 448-453 (2015).

Impregnation of amine functionalized deep eutectic solvents in NH2-MIL-53(Al) MOF for CO2/N2 separation

To improve the CO2/N2 separation performance of metal–organic frameworks (MOFs), amine functionalized deep eutectic solvents (DESs) (choline chloride/ethanolamine (DES1), choline chloride/ethanolamine/diethanolamine (DES2), and choline chloride/ethanolamine/methyldiethanolamine (DES3)) confined in the NH2-MIL-53(Al). NH2-MIL-53(Al) impregnated with DES was synthesized and characterized using N2-sorption analysis and Fourier transform infrared (FTIR) spectroscopy. Morphology of the synthesized MOFs was investigated using scanning electron microscopy (SEM). Also, elemental analysis was determined by energy-dispersive X-ray spectroscopy (EDX). CO2 adsorption isotherms of amine-functionalized DESs impregnated NH2-MIL-53(Al) were measured at temperatures range of 288.15–308.15 K and pressures up to 5 bar. The results reveal that the impregnated MOF with functional group of amine DES improves separation performance NH2-MIL-53(Al). CO2 adsorption capacity of DES1/NH2-MILS-53(Al) was twofold respect to of pristine NH2-MIL-53(Al) at 5 bar and 298.15 K; which helps to guide the logical design of new mixtures for gas separation applications. Also, the heat of adsorption for the synthesized NH2-MIL-53(Al) and DESs/NH2-MIL-53(Al) were estimated. Most importantly, CO2 chemisorption by NH2 group in the sorbent structure has a significant effect on the adsorption mechanism.