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The present review revisits representative studies addressing the development of efficient Pd-based carbon-supported heterogeneous catalysts for two important reactions, namely, the production of hydrogen from formic acid and the hydrogenation of carbon dioxide into formic acid. The HCOOH-CO2 system is considered a promising couple for a hydrogen storage system involving an ideal carbon-neutral cycle. Significant advancements have been achieved in the catalysts designed to catalyze the dehydrogenation of formic acid under mild reaction conditions, while much effort is still needed to catalyze the challenging CO2 hydrogenation reaction. The design of Pd-based carbon-supported heterogeneous catalysts for these reactions encompasses both the modulation of the properties of the active phase (particle size, composition, and electronic properties) and the modification of the supports by means of the incorporation of nitrogen functional groups. These approaches are herein summarized to provide a compilation of the strategies followed in recent studies and to set the basis for a hydrogen storage system attained using the HCOOH-CO2 couple.

In spite of significant efforts to investigate the ability of hydrogenated and fluorinated graphene to conduct heat, little research has focused particularly upon their other thermal properties, such as thermal contraction and heat capacity, which have implications for the development of thermal nanotechnology. In an attempt to determine these thermal properties, a few experiments have been carried out, with rather conflicting results. In the present study, calculations were performed using molecular dynamics to investigate the thermal properties of graphane and fluorographene and especially the phenomena involved. The thermal expansion coefficients and heat capacities of the two-dimensional materials were determined at different temperatures. The results indicated that graphane is thermally contracted more significantly than graphene. The calculated molar heat capacity at constant volume is about 25.00 J/(mol·K) for graphene and about 29.26 J/(mol·K) for graphane. The specific heat capacity of fluorographene is always lower than that of graphane. A negative relationship does exist between the binding energy and the temperature.

Tuc Altaf, Cigdem/0000-0001-9036-5836, Supercapacitor research focuses on cheap, long-lasting electrode materials. As a semiconductor, titanium dioxide (TiO2) is cheap and chemically stable, making it a promising electrode material for supercapacitors. The goal is to improve carbon-based composites by hybridizing conductive materials. The graphitic carbon nitride (g-C3N4) is a stable and common allotrope of C3N4. Its optical, electrical, and structural properties make it a good hybrid system for supercapacitors. With a simple, affordable, and successful thermal decomposition method, we synthesized a TiO2/g-C3N4 composite material. Supercapacitors have 20.6 F g-1 specific capacitance, 63 Wh kg-1 energy density, and 92 % Coulombic efficiency. The TiO2/g-C3N4 composite showed highly stable electrochemical performance even after 10,000 charge-discharge cycles., The authors would like to thank TUBITAK for their financial support under research grant no 122F390., TUBITAK [122F390]

Two-dimensional (2D) materials have attracted tremendous interest ever since the isolation of atomically thin sheets of graphene in 2004 due to the specific and versatile properties of these materials. However, the increasing production and use of 2D materials necessitate a thorough evaluation of the potential impact on human health and the environment. Furthermore, harmonized test protocols are needed with which to assess the safety of 2D materials. The Graphene Flagship project (2013-2023), funded by the European Commission, addressed the identification of the possible hazard of graphene-based materials as well as emerging 2D materials including transition metal dichalcogenides, hexagonal boron nitride, and others. Additionally, so-called green chemistry approaches were explored to achieve the goal of a safe and sustainable production and use of this fascinating family of nanomaterials. The present review provides a compact survey of the findings and the lessons learned in the Graphene Flagship.

This study demonstrates that ammonia concentration when doping carbons using hydrothermal treatment has crucial impact on textural properties. The latter translates into an improvement of the electrochemical performance of carbon materials, when used into electrochemical capacitors, especially at high-rate performance. Nitrogen-doped carbons were synthesized by subjecting tannin to hydrothermal carbonization in ammonia solutions of varying concentrations. After carbonization and CO2 activation, the as-produced activated carbons (ACs) were tested as electrodes for electrochemical capacitors in symmetric configuration using 1 M H2SO4 as aqueous electrolyte. Interestingly, ammonia concentration during the hydrothermal synthesis step did not significantly affect the final N content (ca. 3 and 4 at. %) nor the nitrogen and oxygen functionalities on the surface. However, the use of ammonia had crucial impact on the textural properties developed by CO2 activation, and therefore on the electrochemical performance of the ACs. The best-performing N-doped AC showed specific electrode capacitance values, based on carbon material, of 212 F g−1 at 0.5 A g−1 and outstanding capacitance retention of ca. 71 % at 40 A g−1. It also showed high cycling stability, with capacitance retention of ca. 96 % after 30,000 cycles. Furthermore, this AC outperformed similar reported materials, achieving a specific energy of 4.6 W h kg−1 at 12.1 kW kg−1.

Structurally defined graphene nanoribbons (GNRs) have emerged as promising candidates for nanoelectronic devices. Low band gap (<1 eV) GNRs are particularly important when considering the Schottky barrier in device performance. Here, we demonstrate the first solution synthesis of 8-AGNRs through a carefully designed arylated polynaphthalene precursor. The efficiency of the oxidative cyclodehydrogenation of the tailor-made polymer precursor into 8-AGNRs was validated by FT-IR, Raman, and UV/Vis-near-infrared (NIR) absorption spectroscopy, and further supported by the synthesis of naphtho[1,2,3,4-ghi]perylene derivatives (1 and 2) as subunits of 8-AGNR, with a width of 0.86 nm as suggested by the X-ray single crystal analysis. Low-temperature scanning tunneling microscopy (STM) and solid-state NMR analyses provided further structural support for 8-AGNR. The resulting 8-AGNR exhibited a remarkable NIR absorption extending up to ∼2400 nm, corresponding to an optical band gap as low as ∼0.52 eV. Moreover, optical-pump TeraHertz-probe spectroscopy revealed charge-carrier mobility in the dc limit of ∼270 cm2 V−1 s−1 for the 8-AGNR.

The electrochemical reduction of CO2 to produce sustainable fuels and chemicals has attracted great attention in recent years. It is shown that surface-modified carbons catalyze the CO2RR. This study reports a strategy to modify the surface of commercially available carbon materials by adding oxygen and nitrogen surface groups without modifying its graphitic structure. Clear differences in CO2RR activity, selectivity and the turnover frequency between the surface-modified carbons were observed, and these differences were ascribed to the nature of the surface groups chemistry and the point of zero charge (PZC). The results show that nitrogen-containing surface groups are highly selective towards the formation of CO from the electroreduction of CO2 in comparison with the oxygen-containing surface groups, and the carbon without surface groups. This demonstrates that the selectivity of carbon for CO2RR can be rationally tuned by simply altering the surface chemistry via surface functionalization.

One-step dry ball-milling method was employed to prepare different electrocatalysts based on cobalt(II) or iron(II) phthalocyanines (CoPc and FePc, respectively) supported on commercial carbon materials (CNovel or a carbon black (Vulcan)), controlling the nominal metal content to 1 or 2 wt %. No pre-treatment (e.g., functionalization of the carbon support), solvent addition or post-processing steps (e.g., heat-treatment, acid-treatment, etc.) were required before, during or after the mechanochemical process. Different characterization techniques have been used to study the morphological, physicochemical and electrochemical properties of the synthesized materials. The as-prepared catalysts can be directly used without involving further procedure. Solid-state ball-milling strategy provides excellent contact of both components, which synergistically improved their electrocatalytic performance. Regarding the carbon materials, the adequate nanoarchitecture and surface chemistry of CNovel permits better distribution of metal phthalocyanines (MPc) compared to a carbon black. The FePc supported on CNovel shows excellent electrocatalytic activity for oxygen reduction reaction (ORR), in terms of good selectivity towards the 4-electron pathway, long-term stability and low overpotential in alkaline medium. This study opens new paths for a simple, scalable and cost-effective catalyst manufacturing through mechanochemistry that can be modulated by selecting the proper nanocarbon support and MPc/carbon ratio.

Batteries are the backbones of the sustainable energy transition for stationary off-grid, portable electronic devices, and plug-in electric vehicle applications. Both lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs), most commonly rely on carbon-based anode materials and are usually derived from non-renewable sources such as fossil deposits. Biomass-derived carbon materials are extensively researched as efficient and sustainable anode candidates for LIBs and NIBs. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon anodes for LIBs and NIBs annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, an outlook and some challenges faced in this promising area of research is presented. This review enlightens the readers with valuable insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties, and application of biomass-derived carbon materials as anode candidates for LIBs and NIBs.

The unique structural versatility and chemical and thermophysical properties of carbon make it essentially irreplaceable for non-reductant uses in many high-temperature metallurgical processes. At present, bio-carbon substitutes are not technically feasible for large-scale use in electrode and refractory materials that are vital consumables in the steel, aluminum, and non-ferrous metal industries. Carbon electrodes of all types (including Soderberg, prebaked, and anodes/cathodes for Al) as well as carbon lining pastes are all similar in that they are comprised of a granular carbon aggregate and a carbon-based binder. Similarly, refractories such as MgO-C utilize both natural (mined) graphite and carbon-based binders. Replacements of fossil materials with equivalent bio-carbon substitutes have the potential to dramatically reduce the carbon footprints of these products. However, there are still considerable materials engineering challenges that must be surmounted. The properties of bio-carbon materials and technological obstacles are explored, including catalytic graphitization and development of bio-pitch materials., Part of ISBN 9783031226335QC 20230801

The present contribution describes the synthesis of a carbon supported VPO catalyst with a fibrous structure. The synthesis method is simple, low-cost, scalable and reproducible that allows the formation of the bulk mixed oxide (VO)2P2O7 (VPP) active phase on the carbon support material. The preparation does not require any special reducing thermal treatments due to the ability of the carbon support to stabilize the VPP active phase since this carbon-based support is stable under oxidizing conditions up to around 400ºC allowing it to be used as for catalytic oxidation reactions. The stability of the carbon-supported VPP catalyst under reaction conditions was examined with in situ Raman under oxidizing/ H2 reducing cycles and n-butane oxidation conditions under both wet and dry conditions. These studies confirm the dynamic character of VPO phases, which interconvert under different conditions, and the stability of carbon-supported VPP phase under different environments. The novel carbon-supported catalyst exhibits an activity behavior like that observed for commercial catalysts that suggests a very promising catalytic material.

Bakalářská práce je věnována oxidaci uhlíkatých materiálů (zejména vícevrstvých nanotrubic) synergického účinku pomocí ozonu a teploty. Na úvod v teoretické části byla popsána struktura a vlastnosti uhlíkatých materiálů, možnosti jejich modifikací a způsob charakterizace. Dále v experimentální části byla provedena oxidace použitých materiálů s využitím O3. Nakonec v části věnované charakterizaci byl porovnán stupeň oxidace nanotrubic za různých teplot a časů., The bachelor thesis is devoted to oxidation of carbon materials (especially multi-layer nanotubes) synergistic effect using ozone and temperature. At the beginning in the theoretical part, the structure and properties of carbon materials, the possibilities of their modifications and the way of characterization were described. Next, in the experimental part, oxidation of the materials used was carried out in using O3. Finally, in the section devoted to the characterization, the degree of oxidation of nanotubes at different temperatures and times was compared., Fakulta chemicko-technologická, 1. Prezentace výsledků bakalářské práce. 2. Diskuze k posudku vedoucího bakalářské práce. 3. Studentka zodpověděla všechny dotazy a připomínky k bakalářské práci. Komise uznala bakalářskou práci jako originál, nejedná se o plagiát., Dokončená práce s úspěšnou obhajobou

Pesticides are extensively used in agriculture to enhance crop yield and combat pests and pose a significant threat to ecosystems and human health when their residues accumulate in soil and water. Conventional methods of pesticide removal are often costly or introduce secondary pollutants. The increasing worry about pesticides harming the environment has led to more research on their removal. Various biowaste materials have been investigated for remediation of these contaminants. Among investigated materials, spent coffee grounds, a widely available waste product, offer a promising solution. Coffee consumption is a daily ritual, generating substantial quantities of spent coffee grounds as residual waste. Harnessing the adsorption potential of spent coffee grounds for pesticide removal addresses an environmental challenge and aligns with waste management principles and a circular economy. The carbon material, obtained through a controlled carbonisation process of spent coffee grounds at 900 ºC, showed high adsorption potential for chlorpyrifos. The Langmuir and Freundlich models were employed to analyse the adsorption process, revealing favourable adsorption behaviour at different temperatures. Thermodynamic parameters indicated the spontaneous and feasible nature of the adsorption process, with temperature being an important factor for the adsorption of chlorpyrifos on the investigated material.

Pesticides, whether synthetic or natural, are crucial in managing insects, and weeds, and influencing plant growth. However, the widespread use of organophosphates, a highly effective class of chemical pesticides, raises environmental concerns due to their slow biodegradation, resulting in ecosystem and food chain contamination. The inhibitory effect of organophosphates on acetylcholinesterase contributes to various health disorders. Malathion, commonly used for mosquito and insect control in crops and pet care, exhibits gradual decomposition in water and soil, leading to heightened concentrations in discharge areas and potential risks to aquatic organisms and human health. To address the removal of organophosphates, various methods have been explored, with adsorption standing out for its simplicity, cost-effectiveness, and environmental friendliness. Cellulose-derived carbon materials, characterised by porous structures and large surface areas, provide an efficient solution. This study focuses on utilising cellulose-derived carbon materials as an adsorbent for malathion removal, employing SEM, EDX, FTIR, and BET analysis for comprehensive characterisation. The investigation concentrates on malathion adsorption onto cellulose-derived carbon materials, employing four isotherm models: Freundlich, Langmuir, Temkin, and DubininRadushkevich. The experimental data best fit the Freundlich isotherm, indicating a multilayer adsorption mechanism on the heterogeneous surface of carbon materials. The Langmuir isotherm model shows the maximum adsorption capacities for malathion onto materials CDCM3, CDCM6, and CDCM8, respectively, are 38.67 mg g-1, 170.20 mg g-1, and 254.41 mg g-1. The adsorption energy from the Dubinin-Radushkevich isotherm confirms that the adsorption process for malathion removal is physisorption, while the Temkin isotherm suggests an exothermic process. These findings significantly contribute to sustainable strategies for mitigating the environmental impact

Introduction: The antibacterial activity of graphene oxide (GO) has been widely explored and tested against various pathogenic bacterial strains. Although antimicrobial activity of GO against planktonic bacterial cells was demonstrated, its bacteriostatic and bactericidal effect alone is not sufficient to damage sedentary and well protected bacterial cells inside biofilms. Thus, to be utilized as an effective antibacterial agent, it is necessary to improve the antibacterial activity of GO either by integration with other nanomaterials or by attachment of antimicrobial agents. In this study, antimicrobial peptide polymyxin B (PMB) was adsorbed onto the surface of pristine GO and GO functionalized with triethylene glycol. Methods: The antibacterial effects of the resulting materials were examined by evaluating minimum inhibitory concentration, minimum bactericidal concentration, time kill assay, live/dead viability staining and scanning electron microscopy. Results and discussion: PMB adsorption significantly enhanced the bacteriostatic and bactericidal activity of GO against both planktonic cells and bacterial cells in biofilms. Furthermore, the coatings of PMB-adsorbed GO applied to catheter tubes strongly mitigated biofilm formation, by preventing bacterial adhesion and killing the bacterial cells that managed to attach. The presented results suggest that antibacterial peptide absorption can significantly enhance the antibacterial activity of GO and the resulting material can be effectively used not only against planktonic bacteria but also against infectious biofilms.

Benefitting from its lightweight, low cost and considerable liquid holding capability, bio-based 3D carbon materials with considerable hydrophobicity have stood out as effective oil-water separators to address oily water problems. However, in order to obtain ideal hydrophobicity, recent approaches such as the thermal-induced sp2-hybridization and nano-texturing construction are energy-consuming and complicated, limiting the large-scale production. Here, through the catalysis co-calcination of transition metals salts (TMSs) and biomass precursor, agriculture solid waste-sugarcane residues were successfully converted to hydrophobic photo-thermal metal/carbon materials (CMs) with lower calcination temperature. Comparing with normal carbonization method, catalysis co-calcination can achieve higher carbonization degree and larger yield with lower consumption energy. The as-prepared Cu-CMs can adsorb 18.49 g/g, 31.33 g/g, 24.45 g/g, 38.25 g/g, and 41.98 g/g of DMF, toluene, methanol, chloroform and carbon tetrachloride, respectively, showing excellent adsorption capability towards organic solvents. Moreover, owing to the synergistic photothermal effect of carbon skeleton and metal remains, the metal/carbon materials can heat the oil efficiently and show better adsorption performance for high-viscous oil. The catalysis co-calcination method is demonstrated as a promising method to produce CMs with unique properties and the metal/carbon materials is also supposed to be an effective wastewater treat materials.

Nowadays, environmental pollution caused by antibiotics attracts extensive attention. Adsorption has been successfully applied in the treatment of wastewater loaded by pharmaceutics, while diverse natural and eco-friendly materials have been recognized as promising adsorbents. In this work smectite clay from Bogovina (Serbia) and biopolymer chitosan (derived from waste of crustaceans) were used as eco-friendly starting materials for the adsorbent synthesis. The combination of transition metal, carbon materials, and clay minerals represents a useful way to develop functional nanocomposites with benefiting synergistic properties of all components. Simple, one-step hydrothermal procedure conducted at 180 ℃ for 24h was applied for synthesis of cobalt/smectite/chitosan-derived carbon (H_Co/C-S) nanocomposite. The sample was characterized using XRPD, FTIR, and low-temperature N2-physisorption analysis and tested as adsorbent of ciprofloxacin (CPX). The effects of temperature, initial pH, and CPX concentration on the adsorption process were investigated. The adsorption results were fitted by Langmuir, Freundlich, and Sips adsorption isotherms. Additionally, CPX adsorption was described by appropriate kinetics and thermodynamic parameters. It was found that temperature increase had the beneficial effect on CPX adsorption, while investigated adsorbent was efficient in a broad pH range (4-8). The H_Co/C-S adsorbent was found to be efficient in the removal of CPX antibiotic.

The examination of different raw materials as precursors for obtaining carbon materials is an important area of research due to the wide range of applications for carbon materials in various fields, including energy storage, catalysis, and electronic devices. Some of the commonly studied precursors for carbon materials include biomass, petroleum-based precursors, waste materials, natural materials. The selection of a precursor material depends on various factors, such as the intended application of the carbon material, the availability and cost of the precursor, and the properties of the resulting carbon material. Different precursors can result in carbon materials with varying structures, porosities, and surface chemistries, which can affect their properties and performance in different applications. In our work, we used cherry pits, sour cherry, vineyard peach pits, bean and pea husks. The properties of the initial precursors were tested and then they were treated physically and chemically at different temperatures and times. Correlation of the properties between the initial and final samples was made, as well as their potential application in relation to the obtained properties.

[EN] The coupling of concentrated solar technologies and thermochemical biomass conversion is a promising alternative because there is an improvement on the process efficiency and a reduction of the environmental impact related to the use of fossil fuels for heat process. Therefore, the use of solar pyrolysis of agro-industrial wastes into fuels results attractive due to the biomass versatility to be transformed in a variety of products. In the present work, leaves of agave Angustifolia were used as raw material to performed the solar pyrolysis in the IER-UNAM solar furnace (Mexico) to produce amorphous carbon. The experiments were performed in a borosilicate reactor at different temperatures (450-1550 °C), with an average heating rate of 30 °C/min and 60 min of residence time. The main results show a variety of yields in the char produced from 28-14%, and conversion up to 85%. In addition, according to the temperature range, the amorphous chars produced may be suitable for energy storage in symmetric supercapacitors as carbon electrodes., [ES] El acoplamiento de tecnologías de concentración solar y los procesos termoquímicos de conversión de biomasa son una alternativa prometedora, debido al mejoramiento de la eficiencia del proceso y reducción del impacto medioambiental asociado al uso de combustibles fósiles para la generación de calor de proceso. Por ello, el uso de pirólisis solar de desechos agroindustriales hacia combustibles resulta atractiva debido a la versatilidad de la biomasa para ser convertida en una variedad de productos. En el presente trabajo, hojas de agave Angustifolia fueron usadas como materia prima para llevar a cabo la pirólisis solar en el horno solar del IER-UNAM (México) para la producción de carbón amorfo. Los experimentos se realizaron a diferentes temperaturas (450-1550 °C), con una rampa de calentamiento promedio de 30 °C/min y 60 min de tiempo de residencia. Los resultados principales muestran una variedad en los rendimientos de 28-14 % y una conversión de hasta 85%. Adicionalmente, de acuerdo al rango de temperatura analizado, la producción de carbones amorfos puede ser adecuada para su uso como electrodos en supercapacitores simétricos, para el almacenamiento de energía.

Carbon materials constitute a broad family of solids that encompass a high variety of physical and chemical properties, including morphology. These materials have shown to be very useful as catalysts supports and, in this context, also for the heterogenization of metal complexes owing catalytic properties. This work is mainly, the summary of the results obtained in several research projects focused on developing heterogenized molecular catalysts by exploiting the properties of a plethora of carbon materials to address several immobilization procedures.

Single atoms and nanoclusters of Fe, Ni, Co, Cu, and Mn are systematically designed and embedded in a well-defined C1N1-type material that has internal cavities of ≈0.6 nm based on four N atoms. These N atoms serve as perfect anchoring points for the nucleation of small nanoclusters of different metal natures through the creation of metal-nitrogen (TM-N4) bonds. After pyrolysis at 800 °C, TM@CNx-type structures are obtained, where TM is the transition metal and x < 1. Fe@CNx and Co@CNx are the most promising for oxygen reduction reaction and hydrogen evolution reaction, respectively, with a Pt-like performance, and Ni@CNx is the most active for oxygen evolution reaction (OER) with an EOER of 1.59 V versus RHE, far outperforming the commercial IrO2 (EOER = 1.72 V). This systematic and benchmarking study can serve as a basis for the future design of advanced multi-functional electrocatalysts by modulating and combining the metallic nature of nanoclusters and single atoms.

Formic acid has been postulated as one of the most promising liquid organic hydrogen carriers. Numerous studies dealing with the development of efficient catalysts able to boost the dehydrogenation of formic acid can be found in recent literature. However, most of them lack in stability, so that finding stable catalysts is highly desirable yet challenging. In the present study, we developed Pd-based biomass-derived carbon-supported catalysts by following a simple protocol. The effect of the modification of both the metal phase and support has been assessed by incorporating Ag in the form of bimetallic nanoparticles and nitrogen functional groups, respectively. The effect of the method followed for the preparation of the catalysts was also checked. It has been found that the resulting PdAg-based catalysts supported on N-doped biomass-derived carbon materials showed suitable activity and excellent stability under reaction conditions. The present study highlights the potential of modulating the features of the catalysts, not only in terms of the composition of the metal phase and incorporation of heteroatoms in the support, but also in terms of the synthetic protocol used.

Graphene oxide (GO) is a layered structure similar to graphite, whose planes of carbon atoms are decorated by oxygen-containing groups. These groups bring hydrophilicity and reactivity to GO, as they are present on its basal plane or at the edges. Thus, their identification is essential to determine the chemical properties of GO. Amongst the possible analytical techniques, infrared spectroscopy is suitable to identify these groups. In this work, an advanced spectroscopic method, polarized attenuated total reflectance infrared spectroscopy, was used to obtain a more in-depth analysis of these reactive groups. This new approach has allowed to refine the description of the functional groups at the surface and could be used to follow the evolution surface processes in material chemistry (e.g. grafting reactions).

The extensive use of the toxic organophosphate chlorpyrifos underscores the need for effective methods to eliminate it from the environment [1]. Chlorpyrifos's acute neurotoxicity stems from its irreversible inhibition of acetylcholinesterase, an enzyme crucial for signal transmission in the nervous system. This inhibition can lead to various neurological disorders [1,2]. While several methods have been explored for removing chlorpyrifos from water, adsorption is one of the most promising approaches [3]. Viscose fibers derived from cellulose are frequently investigated as a potential source for producing activated carbon materials [1]. Our study employed carbon materials derived from viscose fibers as an adsorbent for chlorpyrifos. Our findings revealed that 1 gram of these carbon materials could adsorb 171.53 mg, 169.20 mg, and 175.44 mg of chlorpyrifos at a temperature of 25°C. We also delved into the kinetics of batch adsorption to remove chlorpyrifos from water solutions. Kinetics analysis was performed using pseudo-first-order, pseudo-second-order, and Elovich kinetic models. The results indicated that the adsorption of chlorpyrifos onto the carbon materials best followed the pseudo-second-order kinetics model under the specified experimental conditions. The constant rate values were determined to be 0.217 mg g-1 min-1 , 0.076 mg g-1 min-1 , and 0.491 mg g-1 min-1 under experimental conditions.

Engineering the surface chemistry of carbon-based materials is of crucial importance in tuning their intrinsic properties, including electrical conductivity, wettability, electroactivity, adsorption potential, reactivity, physical and chemical stability. Intense research has recently focused on understanding the role of surface oxygen functional groups when carbon materials are in contact with an electrolyte or solvent in order to tailor and improve them for technological applications. For this purpose, their synthesis method and/or further oxidation treatments should be carefully selected, since they can substantially influence not only the oxygen content, but also the nature of the oxygen moieties, which could be decisive in determining the surface properties of the resulting material. The combined use of different chemical, spectroscopic and electrochemical techniques, provides unique and reliable information about the contribution of a specific oxygen-containing group in the surface (electro)chemistry of carbon-based materials. This paper provides a discussion of the role of oxygen heteroatoms in the surface electrochemistry of a carbon material as they relate to their influence on both its electroactivity and reactivity.

Efficient CO2/C2H2 separation at ambient conditions is an essential but challenging process owing to their similar molecular sizes and physical properties. In this work, a novel approach of charge/strain-regulated gas capture and separation was proposed, which offered the advantages of reversibility and controllable kinetics. Highly selective CO2 separation from CO2/C2H2 with porous g-C9N7 nanosheets were demonstrated with varying charge densities and strains using molecular dynamics (MD) simulations and first-principle density function theory (DFT) calculations. The remarkable CO2 permeance up to 5.85 x 10(7) GPU can be achieved by charge engineering. Under the condition of tensile strain, a controllable CO2 separation performance was exhibited, whose CO2 permeance increased with increasing the applied strain. The maximum permeance was 3.44 x 10(7) GPU with 9% strained g-C9N7 membrane. More interestingly, a promising approach combining the charge regulation with strain engineering was explored to investigate the synergistic effect. Under conditions of 2 e(-) charge and 3% tensile strain on g-C9N7 membrane, the CO2 permeance reached 4.24 x 107 GPU, which was 1.6 times of CO2 permeability when only 2 e(-) was added and 10 times of CO2 permeance when only 3% strain was added. Additionally, the energy barrier of CO2 decreased with the increasing degree of regulation (charge and strain engineering) on the g-C9N7 membrane, indicating that the g-C9N7 membrane can be served as an excellent candidate for CO2/C2H2 separation. These results provide useful guidance for developing advanced materials and applying new regulation techniques to realize highly tunable and selective CO2/C2H2 separation.

Дисертаційна робота присвячена створенню симетричних суперконденсаторів з покращеними питомими параметрами та створенню на їх основі гібридних джерел живлення із збільшеним строком експлуатації. В роботі досліджується вплив пористої структури вуглецевих матеріалів на параметри cуперконденсаторів. Для математичного опису процесів, що протікають в пористих електродах, запропоновані дві нові теоретичні моделі. Спираючись на результати експериментальних досліджень і теоретичних розрахунків, визначено склад і конструкції електродів для високоємних та високопотужних суперконденсаторів. Питома ємність суперконденсатора, виготовленого з використанням результатів роботи, склала 9,1 Вт-год/кг. В роботі досліджується робота гібридних джерел живлення виготовлених на базі блоків суперконденсаторів. Запропоновані зовнішні електронні пристрої, які забезпечують тривалу стабільну роботу гібридного джерела живлення

N-doped carbon materials have been considered one of the most promising options for the replacement of platinum-based electrocatalysts towards the oxygen reduction reaction (ORR). This work provides insights into the deactivation routes of N-doped carbon materials. The changes occurring in the active sites of N-doped carbon catalysts have been analyzed in detail through pre- and post-ORR characterization by XPS of selectively N-doped carbon materials. Moreover, computational modelling was used to deepen into the deactivation mechanism of N-doped carbon materials in the ORR. From XPS and computational modelling, it can be concluded that the deactivation of graphitic-type nitrogen species, during the ORR in both acidic and alkaline environments, occurs through oxidation and tautomerization reactions that result in the formation of N–C–O-type groups. In acidic environment, the reaction kinetics is slower due to the high stability of the ORR intermediates. In alkaline electrolyte, the N–C–O-type groups can be easily formed due to the interaction of graphitic-type N species and the OH− anions from the electrolyte. In this case, the catalytic activity is due to the contribution of both graphitic nitrogen groups and N–C–O species.

This review article is dedicated to the memory of Francisco (Paco) Rodríguez-Reinoso (Granada 1941 - Alicante 2020). Paco dedicated more than 56 years of his life to research on carbon materials, covering from their synthesis and characterization, to their evaluation using a range of processes such as gas adsorption/separation, heterogeneous catalysis, and drug delivery, among others. His extensive research was mainly performed in the Advanced Materials Laboratory (LMA) located at the University of Alicante, Spain. This research has been reflected in more than 400 research articles in high quality international journals. This review article summarizes some of Paco’s main achievements in carbon-related research emphasizing his main contributions and perspectives in the field.

Ionic liquids (ILs) are a group of non-conventional salts with melting points below 100 degrees C. Apart from their negligible vapor pressure at room temperature, high thermal stability, and impressive solvation properties, ILs are characterized by their tunability. Given such nearly infinite combinations of cations and anions, and the easy modification of their structures, ILs with specific properties can be synthesized. These characteristics have attracted attention regarding their use as extraction phases in analytical sample preparation methods, particularly in liquid-phase extraction methods. Given the liquid nature of most common ILs, their incorporation in analytical sample preparation methods using solid sorbents requires the preparation of solid derivatives, such as polymeric ILs, or the combination of ILs with other materials to prepare solid IL-based composites. In this sense, many solid composites based on ILs have been prepared with improved features, including magnetic particles, carbonaceous materials, polymers, silica materials, and metal-organic frameworks, as additional materials forming the composites. This review aims to give an overview on the preparation and applications of IL-based composites in analytical sample preparation in the period 2017-2020, paying attention to the role of the IL material in those composites to understand the effect of the individual components in the sorbent., Iontové kapaliny (IL) jsou skupina nekonvenčních solí s teplotou tání pod 100 °C. Kromě jejich zanedbatelné tenze par při pokojové teplotě, vysoké tepelné stability a příznivých solvatačních vlastností se IL vyznačují svou laditelností. Vzhledem k téměř nekonečné kombinaci kationtů a aniontů a snadné modifikaci jejich struktur lze syntetizovat IL se specifickými vlastnostmi. Tyto vlastnosti přitahovaly pozornost, pokud jde o jejich použití jako extrakčních fází v metodách přípravy analytických vzorků, zejména v metodách extrakce v kapalné fázi. Vzhledem k tekuté povaze nejběžnějších IL jejich začlenění do metod analytického zpracování vzorků s použitím tuhých sorbentů vyžaduje přípravu derivátů, jako jsou polymerní IL, nebo kombinace IL s jinými materiály pro přípravu tuhých kompozitů na bázi IL. V tomto smyslu bylo připraveno mnoho tuhých kompozitů na bázi IL s vylepšenými vlastnostmi, včetně magnetických částic, uhlíkatých materiálů, polymerů, materiálů z oxidu křemičitého a metalo-organických struktur, jako dalších materiálů tvořících kompozity. Cílem této studie je poskytnout přehled o přípravě a aplikacích kompozitů na bázi IL při analytickém zpracování vzorků v období 2017–2020, přičemž je třeba věnovat pozornost úloze materiálu IL v těchto kompozitech, aby bylo možné pochopit účinek jednotlivých složek sorbentu.

[EN] LaMn1-xCoxO3 perovskites were synthesized by a modified sol-gel method which incorporates EDTA. These materials' electrochemical activity towards both oxygen reduction (ORR) and oxygen evolution reactions (OER) was studied. The cobalt substitution level determines some physicochemical properties and, particularly, the surface concentration of Co and Mn's different oxidation states. As a result, the electroactivity of perovskite materials can be tuned using their composition. The presence of cobalt at low concentration influences the catalytic activity positively, and better bifunctionality is attained. As in other perovskites, their low electrical conductivity limits their applicability in electrochemical devices. It was found that the electrochemical performance improved significantly by physically mixing with a mortar the active materials with two different carbon black materials. The existence of a synergistic effect between the electroactive component and the carbon material was interpreted in light of the strong carbon-oxygen-metal interaction. Some mixed samples are promising electrocatalysts towards both ORR and OER.

With the continuous increase of global population and consumption of resources, the dire need for an efficient and reliable energy system is becoming progressively prominent. The current energy system is still heavily dependent on fossil fuel, which is limited and harmful to the environment. In recent years, many countries have taken the initiative to transition into a phase where renewable and clean energy sources are gradually replacing fossil fuels and applied in various scenarios from residential buildings to power grids. However, renewable energies has their intrinsic drawbacks because of their intermittent and fluctuating nature. Consequently, it is crucial for the energy storage system to be highly capable in terms of storage capacity, instant supply, and durability. Among various energy storage systems, lithium-ion batteries have emerged as a preferable choice because of its high capacity, chemical and thermal stability, and gradually decreasing cost. In this dissertation, we developed a series of composite electrode materials for lithium-ion batteries of high performance and low cost. Carbonaceous materials have been reported to improve the battery performance to a certain extent. However, the lack of focus in the designing of the architecture of the carbon materials could limit the effect that they might bring. We thus developed an intercalation method that allows FeCl3 to be directly embedded into the graphite matrix to synthesize LFP/Graphite as a cathode material. This method significantly increased electronic and ionic conductivity through a robust and highly conductive graphite matrix, tremendously improving the performance of commercial LFP to a reversible capacity of 160 mA h g-1, a rate performance of 107 mA h g-1 at 60 C, and an outstanding cycling ability of > 95% reversible capacity retention over 2000 cycles.The intercalation method is then combined with Fe2O3 to improve the performance of graphite, which is the most prevalent material of th

Esta tesis doctoral se centra en el desarrollo de diferentes métodos electroquímicos y químicos para la funcionalización de materiales de carbono nanoestructurados, obteniendo materiales electródicos funcionales para aplicaciones bioelectroquímicas. En este sentido, las propiedades en superficie influyen directamente en la interacción entre el elemento bioreceptor o biocatalizador con el electrodo. Por tal motivo, se puede mejorar la cinética de transferencia de electrones, la inmovilización, orientación y distribución del bioelemento en el electrodo, mejorando el rendimiento del dispositivo bioelectroquímico, a partir de la química superficial del material empleado. El uso de diferentes funcionalidades de nitrógeno y fósforo generados electroquímicamente sobre los materiales de carbono nanoestructurados proporciona una plataforma para la síntesis controlada, para mejorar la actividad catalítica de biocatalizadores. Además, el proceso electroquímico de funcionalización ha demostrado ser una ruta interesante para preparar bioelectrodos en un solo paso, con bajo consumo de elementos enzimáticos y un rendimiento sobresaliente a los métodos convencionales actuales. Por otro lado, el uso de materiales de carbono dopados en N cuaternarios como elemento transductor en la síntesis de un biosensor enzimático de glucosa libre de metales proporciona, en condiciones aeróbicas, un biosensor de alta sensibilidad para la detección de glucosa en orina y bebidas azucaradas comerciales, con bajo efecto de los interferentes y alta estabilidad. Finalmente, la modificación de los nanotubos de carbono con nanopartículas de oro proporciona un material de electrodo transductor escalable y estable en el que tiene lugar la inmovilización de anticuerpos a través de interacciones Au-8. La formación de antígeno-anticuerpo complejo provoca efectos estéricos que producen un impedimento para la transferencia de electrones proveniente de una sonda redox activa hacia la superficie del electrodo, lo

LaMn1−xCoxO3 perovskites were synthesized by a modified sol-gel method which incorporates EDTA. These materials’ electrochemical activity towards both oxygen reduction (ORR) and oxygen evolution reactions (OER) was studied. The cobalt substitution level determines some physicochemical properties and, particularly, the surface concentration of Co and Mn’s different oxidation states. As a result, the electroactivity of perovskite materials can be tuned using their composition. The presence of cobalt at low concentration influences the catalytic activity positively, and better bifunctionality is attained. As in other perovskites, their low electrical conductivity limits their applicability in electrochemical devices. It was found that the electrochemical performance improved significantly by physically mixing with a mortar the active materials with two different carbon black materials. The existence of a synergistic effect between the electroactive component and the carbon material was interpreted in light of the strong carbon–oxygen–metal interaction. Some mixed samples are promising electrocatalysts towards both ORR and OER.

Freezing/melting behavior of water confined in the nanopores of activated carbon materials has been evaluated using differential scanning calorimetry (DSC) at different water loadings, and after the application of an external stimulus. Under atmospheric pressure conditions, the DSC scans show a depression in the freezing/melting point of confined water compared to the bulk system. Interestingly, water confined in narrow micropores (pores below 0.7 nm) does not exhibit any phase transition, i.e. it is non-freezable water. Inelastic neutron scattering (INS) data confirm the presence of a distorted molecular assembly in narrow micropores, whereas synchrotron X-ray powder diffraction data (SXRPD) demonstrate the non-freezable nature of the water confined in these narrow-constrictions. Similar experiments under high-pressure CH4 give rise to a completely different scenario. Under high-pressure conditions methane hydrates are formed with a water-to-hydrate yield of 100% for the under-saturated and saturated samples, i.e. in the presence of an external stimulus even water in narrow micropores is prone to experience a liquid-to-solid phase transition. These results confirm the beneficial role of carbon as a host structure to promote nucleation and growth of methane hydrates with faster kinetics and a higher yield compared to the bulk system and to other porous materials.

Sulfonic carbons are very promising and sustainable acid catalysts prepared from renewable precursors. The properties of the final catalysts are customizable, including morphological (particle size and shape), textural (surface area and porosity), hydrophilic/hydrophobic, and acidic properties. In this chapter, we present a brief overview of the different carbon materials, with their properties and the methods for their modification, the procedures to introduce sulfonic groups and the available techniques for their characterization, as well as some examples of catalytic applications and the deactivation mechanisms detected for this kind of materials. This revision will serve as guideline for research in new directions for streamlining the application of this versatile acid catalyst.

Carbon plays a significant role in the development of electrode materials used in, for example, catalysis, energy storage and sensing. Graphene-based coatings and carbon nanotubes have expanded that role through nanostructuring of hybrids or the formation of composites. In particular, the formation of hybrids of nanocarbons with iridium oxide yield nanostructured materials through direct anodic deposition, which have substantially improved charge capacities vs. pure IrOx. Modification of the possible redox sites, new structuring of the hybrids and increased charge capacities are expected as a result. This work shows that nitrogen (N)-doped graphenes, as part of an IrOx hybrid, offer a new redox chemistry on graphene oxide through electrochemical modulation of the redox states of nitrogen in graphene, and yield stable nitro groups bound to carbon, which have, so far, the largest oxidation state reported in N-doped graphene. The hybrid materials are obtained in the form of coatings thanks to spontaneous adhesion of iridium oxo species on N-doped graphenes and further anodic electrodeposition of the mixture. While the oxidizing synthesis process already involves modification of the oxidation state of nitrogen, further electrochemical cycling evidences the electrochemical processes for both the IrOx and N groups attached to the graphene oxide. All the hybrids obtained present a wide range of nitrogen-based groups that include the nitro group, and a significant charge capacity that remains large upon electrochemical cycling and that involves all the faradaic processes from the iridium and graphene components. One hybrid, in particular, which includes the highest starting oxidation state, reaches a significantly higher charge capacity, higher even than the graphene oxide hybrid, and with 70% retention upon cycling. Although nitrogen doping of graphene is considered to be a reducing process, this study shows that an oxidizing range of nitrogen doping is also possible. IrOx

The rapid development of personalized, portable and wearable electronic devices calls for high performance lithium-ion batteries (LIBs). Molybdenum disulfide (MoS2), a representative two-dimensional (2D) transition metal dichalcogenides (TMDs) material, is a promising anode material with a high theoretical capacity of 670 mAh g-1. However, it suffers from low conductivity, restacking problem and volume changes that limit its commercial application. The goal of this thesis is to develop high-performance porous MoS2/carbon materials (MC) anodes for LIBs, by applying the strategies of creating a 3D porous structure and incorporating with carbon materials. A 3D porous structure with large surface area can not only facilitate electrolyte ions diffusion but also accommodate the volume changes of MoS2. The incorporated carbon materials are able to separate MoS2 layers thus suppressing their restacking problem as well as act as fast electrons pathways with an enhanced conductivity. The excellent mechanical properties of carbon materials also facilitate the realization of good flexibility in MC film electrodes for flexible batteries. In this thesis, two types of materials, MoS2/nitrogen-doped carbon nanotubes (MoS2/CNT) nanocomposites and freestanding flexible MoS2/reduced graphene oxide (MoS2/rGO) films, have been developed. Polypyrrole (PPy) and liquid crystalline graphene oxide (LCGO) are employed as the carbon sources to produce nitrogen-doped carbon and rGO for their incorporation with MoS2, respectively. Combined with the created 3D porous structures, these MC composites all demonstrate a greatly improved electrochemical performance. Most importantly, a facial LCGO-based self-assembly process is developed for fabricating freestanding, flexible and porous MoS2/rGO films.

Electronic waste (e-waste) is growing at an accelerated rate and is regarded as an aggravating economic, environmental, and social health problem globally. It’s a complex waste containing precious and toxic metals, plastics etc. which if recycled properly, can provide a range of environmental and economic benefits. Majority of the current technologies are focused solely on high-value precious and base metal recovery. Despite accounting for large proportion of e-waste, recycling of plastics has suffered, mainly due to lack of economic incentives in their recovery which is further exacerbated by their complex chemical composition and presence of harmful additives. Consequently, plastics have generally been landfilled/incinerated leading to pollution and resource depletion.This thesis aims at addressing this scenario and encompasses the development of several novel processes to recycle e-waste plastics. It demonstrates how their secondary use may potentially divert them from landfills and contribute to many high-end value-added applications such as energy storage. Styrene acrylonitrile type plastics from end-of-life printers (provided by an e-waste recycler in Sydney) were selected for this work.Firstly, the plastics were used as carbon source/reductant to extract iron from another low-value and Fe3O4-rich component of e-waste i.e. toner powder. A qualitative mechanism was proposed for the reduction of iron-oxide to metallic iron. Next, hydrocarbon oils with high calorific values (38.27 MJ/kg) were generated via non-catalytic thermal transformation of plastics. These oils were characterised using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy followed by detailed qualitative mechanism for the formation of major oil components such as styrene, toluene, and naphthalene. The solid carbonaceous residues obtained from thermal transformation process were activated at 700-900 oC to produce porous activated carbons. Supercapacitor electrodes p

The emissions of nitrogen oxides (NOx) are a serious environmental problem due to its relationship with the formation of smog, acid rain and because they are dangerous for human and animal health. These gases are produced in high quantities in diesel engines used for automotive applications, and different strategies are being used to reduce them, among which are the Selective Catalytic Reduction (SCR) systems. For its operation, it is necessary a supply of ammonia as NOx reducing agent, but the inefficiency at low temperatures of the systems used nowadays has led to the conception of the solid ammonia storage units (ASS). Unfortunately, the materials currently used, i.e. metal halides, do not meet the ammonia supply requirements at low temperatures and have problems of swelling and agglomeration. In order to find a material with better properties for its application as an ammonia sorbent material, MgCl2 composites with different carbon materials (graphite, graphene, and SWCNTs) were prepared by direct mixing and wet impregnation methods, and characterized in this work. Despite the decrease of total storage capacity, improvements were found in thermal stability and mass retention, as well as in sorption and desorption kinetics, making these materials a first result towards the improvement of the solid ammonia storage units.

The catalytic hydrolysis of cellulose allows the transformation of this sustainable and renewable raw material to obtain biofuels and high-added value chemicals. The process requires acidic catalysts, which should be preferably solid in order to make it greener and, thus, this work proposes the use of functionalized carbon materials for such an application. A mesoporous commercial carbon of trade name SA-30, abbreviated as SA in this work, has been chemically treated at room temperature to create acidic surface oxygen functional groups. The prepared carbon catalysts have been thoroughly characterized by N2 adsorption-desorption at − 196 ºC, temperature programmed desorption and X-ray photoelectron spectroscopy. SAS carbon (prepared by treatment with a saturated solution of (NH4)2S2O8 in 1 M H2SO4 and named by adding S to the name of the original carbon) is the most effective of the studied catalysts. It allows achieving high cellulose conversion (about 61%) and glucose selectivity. Thus, the low-cost functionalized carbons prepared at mild conditions are effective and promising catalysts for the transformation of cellulose into glucose.