Carbon-supported Iron Research Articles

Ordered mesoporous carbon-supported iron vanadate anode for fast-charging, high energy density, and stable lithium-ion batteries

Ordered mesoporous carbon-supported iron vanadate anode for fast-charging, high energy density, and stable lithium-ion batteries

Superefficient non-radical degradation of benzo[a]pyrene in soil by Fe-biochar composites activating persulfate

Efficient decomposition of organic pollutants in complex soil environments through non-radical pathways is vital but challenging. Herein, biochar supported nZVI (nZVI@BC800) fabricated by carbothermal reduction method was prepared for persulfate activation, exhibiting ultrafast degradation efficiency of benzo[a]pyrene of 71.80 % within 5 min with excellent adaptability to wide pH range of 3.0–9.0 and high anti-interference capacity to coexisting substances in soil. In nZVI@BC800/persulfate system, non-radical pathways including singlet oxygen (1O2) and electron transfer made dominant contributions to benzo[a]pyrene degradation. 1O2 could be produced not only by the reaction between C = O on BC800 and persulfate, but also via the transformation of O2∙- and ∙OH. On the other hand, biochar as an electron shuttle could accelerate electron transfer from benzo[a]pyrene to persulfate adsorbed on the catalyst. Additionally, possible degradation pathways of benzo[a]pyrene in nZVI@BC800/persulfate system were inferred through GC–MS and DFT calculations. Furthermore, the system could modulate the soil microbial community to further improve plant stress resistance. Therefore, this study provided a promising strategy via developing carbon-supported iron catalyst for carrying out persulfate-based non-radical pathways to remediate organic-polluted soil.

ZIF-8 pyrolized N-doped carbon-supported iron catalysts for enhanced CO2 hydrogenation activity to valuable hydrocarbons

The N atom in the nitrogen-doped carbon materials can promote the adsorption and conversion of CO2. In addition, as a bridge between N and Fe, the degree of graphitization of carbon supports significantly affects the electron transfer process.

Removal of Cr6+ ions and mordant violet 40 dye from liquid media using Pterocladia capillacea red algae derived activated carbon-iron oxides

In recent years, water pollution has become one of the most dangerous problems facing the world. Pollution of water with heavy metals and different dyes has caused many harmful effects on human health, living organisms and our environment. In this study, iron oxide nanomagnetic composite from Pterocladia Capillacea red algae-derived activated carbon (PCAC-IO) was synthesized by co-precipitation method using different iron salts and different base solutions. The synthesized nanocomposite was investigated with various characterization techniques such as FTIR, BET, SEM-EDX, TEM, XRD, and VSM. The obtained PCAC-IO adsorbent was used for Cr6+ ions and Mordant Violet 40 (MV40) dye removal. The adsorption mechanism of Cr6+ ions and MV40 dye on PCAC-IO was examined using several adsorption and kinetic isotherm models. Langmuir and Freundlich models were investigated using experimental data. Pseudo-first-order (PFO), Pseudo-second-order (PSO) and intraparticle diffusion models (IPDM) were applied to identify the adsorption mechanism. It has shown that the PSO kinetic model fits better with the experimental data obtained from PCAC-IO. This result can be interpreted as the adsorption of the adsorbate on the nanocomposite as chemical adsorption. The optimum conditions for maximum Cr6+ ions removal (96.88%) with PCAC-IO adsorbent occur at room temperature, 5 g L−1 adsorbent concentration, 100 mg L−1 initial pollutant concentration, pH 1 and at the end of 180 min, while maximum MV40 dye removal (99.76%), other conditions being the same, unlikely it occurred at pH 2.06 and after 45 min. The most suitable model for Cr6+ ions removal under the conditions of 1 L−1 g adsorbent concentration and 400 mg L−1 adsorbate concentration was Langmuir (Qmax = 151.52 mg g−1), while for MV40 removal it was Freundlich (Qmax = 303.03 mg g−1). We propose the use of activated carbon-supported iron oxide prepared from bio-waste material, especially from Pterocladia Capillacea red algae, as a promising adsorbent with high efficiency in the removal of Cr6+ ions and MV40 dye from aqueous media.

Effects of various carbon-supported iron catalysts on tar removal efficiency and syngas yield during catalytic biomass gasification

Raw biomass, biochar, and activated carbon (AC) were used to produce carbon supported iron catalysts for catalytic biomass gasification. K2CO3 was used to activate the biochar and provide the K promoter of the catalysts. The results showed that the catalyst prepared by co-impregnating and calcining Fe and K on the raw biomass (B-Fe-K) could remove 80.23 % tar, which was much higher than 73.73 % for the catalyst of B-Fe without the K promoter, and 76.25 % for the catalyst by co-impregnating and calcining Fe and K on the biochar (C-Fe-K). The supports of AC and biochar themselves could also remove 63.16 % and 37.23 % tar, respectively. The use of B-Fe-K almost doubled the syngas yield to 473.79 ml/g (including 243.56 ml/g CO, 198.25 ml/g H2, and 31.98 ml/g CO2), compared to 241.37 ml/g syngas (including 108.98 ml/g CO, 66.41 ml/g H2, and 65.987 ml/g CO2) produced by the pyrolysis of biomass without a catalyst. The addition of biochar during the pyrolysis slightly increased the syngas yield to 248.96 ml/g (117.36 ml/g CO, 74.22 ml/g H2, and 57.38 ml/g CO2) while the use of AC could significantly increase the syngas yield to 347.60 ml/g (179.39 ml/g CO, 124.22 ml/g H2, and 43.99 ml/g CO2). It was found that the porosity, dispersion of active sites and the oxidation state of iron oxide are substantial factors determining the performance of catalysts in tar removal efficiency. The addition of potassium and enhancing the porosity of the catalysts enhanced the reducibility of iron resulted in increasing the tar removal efficiency and gas yield.

Unraveling the roles of microporous and micro-mesoporous structures of carbon supports on iron oxide properties and As (V) removal performance in contaminated water

This study investigates the impact of microporous (SP–C) and micro-mesoporous carbon (DP-C) supports on the dispersion and phase transformation of iron oxides and their arsenic (V) removal efficiency. The research demonstrates that carbon-supported iron oxide sorbents exhibit superior As(V) uptake capacity compared to unsupported Fe2O3, attributed to reduced iron oxide crystallite sizes and As(V) adsorption on carbon supports. Maximum As(V) uptake capacities of 23.8 mg/g and 18.9 mg/g were achieved for Fe/SP-C and Fe/DP-C at 30 wt% and 50 wt% iron loading, respectively. The study reveals a nonlinear relationship between As(V) sorption capacity and iron oxide crystallite size after excluding As(V) adsorption capacity on carbon supports, suggesting the iron oxide phase (Fe3O4) plays a role in determining adsorption capacity. Iron oxide-loaded DP-C sorbents exhibit faster adsorption rates at low As(V) concentrations (5 mg/L) than SP-C sorbents due to their bimodal pore structure. Adsorption behavior varies at higher As(V) concentrations (45 mg/L), with Fe/DP-C reaching maximum capacity more slowly due to limited available adsorptive sites. All adsorbents maintained near-complete As(V) removal efficiency over five cycles. The findings provide insights for designing more efficient adsorbents for As(V) removal from contaminated water sources.

Graphene Nanoflake- and Carbon Nanotube-Supported Iron-Potassium 3D-Catalysts for Hydrocarbon Synthesis from Syngas.

Transformation of carbon oxides into valuable feedstocks is an important challenge nowadays. Carbon oxide hydrogenation to hydrocarbons over iron-based catalysts is one of the possible ways for this transformation to occur. Carbon supports effectively increase the dispersion of such catalysts but possess a very low bulk density, and their powders can be toxic. In this study, spark plasma sintering was used to synthesize new bulk and dense potassium promoted iron-based catalysts, supported on N-doped carbon nanomaterials, for hydrocarbon synthesis from syngas. The sintered catalysts showed high activity of up to 223 μmolCO/gFe/s at 300-340 °C and a selectivity to C5+ fraction of ~70% with a high portion of olefins. The promising catalyst performance was ascribed to the high dispersity of iron carbide particles, potassium promotion of iron carbide formation and stabilization of the active sites with nitrogen-based functionalities. As a result, a bulk N-doped carbon-supported iron catalyst with 3D structure was prepared, for the first time, by a fast method, and demonstrated high activity and selectivity in hydrocarbon synthesis. The proposed technique can be used to produce well-shaped carbon-supported catalysts for syngas conversion.

Synthesis of novel carbon-supported iron oxide sorbents for adsorption of dye from aqueous solutions: equilibrium and flow-through studies

Textile effluents contain dyes that negatively affect water bodies and inhibit photosynthesis by reducing sunlight penetration. This study investigated the adsorption capacity of an iron oxide sorbent immobilised on naturally derived carbon foam for the removal of organic methylene blue dye from water. In this study, the carbon precursor and iron oxide precursor were mixed and carbonised in a single vessel. Baking and carbonization of the natural grain combination produce a porous structure that can act as an effective support for the iron oxide particles. The carbon foam prepared had a self-assembled structure with flour as a basic element. Sorbents of 6 weight (wt)%, 15 wt% iron, and a 0 wt% iron control sample were prepared. Transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) techniques were used to examine the synthesised carbon foam physical properties and surface morphology. The adsorption capabilities were investigated in batch tests by determining the effects of an increase in iron content, sorbent dosage, contact time, and dye concentration. Breakthrough curves were obtained by varying the height of the sorbent bed and varying the flowrate of the dye solution. A higher bed height corresponds to a greater amount of adsorbent. The breakthrough and equilibrium adsorption capacities were found to increase with increasing bed height. When the flow rate is high, the dye solution leaves the column before equilibrium, resulting in shorter breakthrough and saturation times. Higher bed heights and lower flow rates resulted in optimal dye removal in the flow through the system. Breakthrough time increases with increasing iron content. The 15 wt% iron sample displayed superior adsorption capabilities than the 6 wt% sample, while the 0 wt% iron control sample displayed minimal adsorptive capabilities. The pseudo-first order kinetic model was the best fit model for this study (R2 > 0.96), and the adsorption equilibrium is best described by the Freundlich isotherm (R2 > 0.99). The results showed that an iron oxide sorbent immobilised on carbon foam made from natural sources is a good adsorbent for removing methylene dye.

The Conversion of Waste Biomass into Carbon-Supported Iron Catalyst for Syngas to Clean Liquid Fuel Production

Syngas has been utilized in the production of chemicals and fuels, as well as in the creation of electricity. Feedstock impurities, such as nitrogen, sulfur, chlorine, and ash, in syngas have a negative impact on downstream processes. Fischer–Tropsch synthesis is a process that relies heavily on temperature to increase the production of liquid fuels (FTS). In this study, waste biomass converted into activated carbon and then a carbon-supported iron-based catalyst was prepared. The catalyst at 200 °C and 350 °C was used to investigate the influence of temperature on the subsequent application of syngas to liquid fuels. Potassium (K) was used as a structural promoter in the Fe-C catalyst to boost catalyst activity and structural stability (Fe-C-K). Low temperatures (200 °C) cause 60% and 80% of diesel generation, respectively, without and with potassium promoter. At high temperatures (350 °C), the amount of gasoline produced is 36% without potassium promoter, and 72% with promoter. Iron carbon-supported catalysts with potassium promoter increase gasoline conversion from 36.4% (Fe-C) to 72.5% (Fe-C-K), and diesel conversion from 60.8% (Fe-C) to 80.0% (Fe-C-K). As seen by SEM pictures, iron particles with potassium promoter were found to be equally distributed on the surface of activated carbon.

Synthesis of carbon supported iron oxide nanochips and their composite with glutathione: A novel electrochemical sensitive material

In this study, bare iron oxide nanochips (NCs), carbon-supported iron oxide nanochips (C@α-Fe2O3), and glutathione-supported C@α-Fe2O3 nanocomposite (Glu/C@α-Fe2O3) were synthesized. As-synthesized materials were inspected using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and a UV-visible absorption approach. Physical investigations confirmed the synthesis of rhombohedral phased α-Fe2O3, whereas FESEM certified nano-sized material formation. Voltammetry and impedance studies were used to evaluate and compare the electrochemical sensing activities. The electrochemical behavior of the Glu/C@α-Fe2O3 nanohybrid was investigated using differential pulse voltammetry (DPV) to identify their sensitivity towards 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP). The stability of the square wave voltammetry SWV signals was detected in the range of 50–0.05 μM for both 2-NP and 4-NP. All electrochemical factors that influence the effectiveness of the developed sensors, including pH of the medium, accumulation time, and the influence of supporting electrolytes were thoroughly investigated. The sensor-based on our prepared electroactive material demonstrated remarkable electrocatalytic activity and good conductivity with a broad linear range, a low detection limit and high sensitivity for nitrophenol isomer reduction. We also tested the sensor for practical applications in water samples. These results showed that the suggested method could be used in the future to detect potentially dangerous environmental pollutants in water samples.

Adsorption-enforced Fenton-like process using activated carbon-supported iron oxychloride catalyst for wet scrubbing of airborne dichloroethane

Wet scrubbing is a low-cost process for disposing of air pollutants. Nevertheless, this method is rarely used for the treatment of volatile organic compounds (VOCs) because of their poor water solubility. In this study, we used a unique wet scrubbing system containing H2O2 and activated carbon (AC)-supported iron oxychloride (FeOCl) nanoparticles to remove airborne dichloroethane (DCE). The operating conditions of the wet scrubber were optimized, and the mechanism was explored. The results showed that the adsorption of dissolved DCE onto AC promoted its transfer from air to water, while the accumulation of DCE on AC facilitated its oxidation by •OH generated on FeOCl catalyst. The wet scrubber performed well at pH 3 and low H2O2 concentrations. By pulsed or continuous dosing H2O2, the cooperative adsorption-catalytic oxidation allowed long-term DCE removal from air. Benefiting from satisfactory cost-effectiveness, avoidance of toxic byproduct formation, and less corrosion and catalyst poisoning, wet scrubbers coupled with cooperative adsorption and heterogeneous advanced oxidation processes could have broad application potentials in VOC control.

Dynamics at Polarized Carbon Dioxide–Iron Oxyhydroxide Interfaces Unveil the Origin of Multicarbon Product Formation

Surface-sensitive ambient pressure X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy combined with an electrocatalytic reactivity study, multilength-scale electron microscopy, and theoretical modeling provide insights into the gas-phase selective reduction of carbon dioxide to isopropanol on a nitrogen-doped carbon-supported iron oxyhydroxide electrocatalyst. Dissolved atomic carbon forms at relevant potentials for carbon dioxide reduction from the reduction of carbon monoxide chemisorbed on the surface of the ferrihydrite-like phase. Theoretical modeling reveals that the ferrihydrite structure allows vicinal chemisorbed carbon monoxide in the appropriate geometrical arrangement for coupling. Based on our observations, we suggest a mechanism of three-carbon-atom product formation, which involves the intermediate formation of atomic carbon that undergoes hydrogenation in the presence of hydrogen cations upon cathodic polarization. This mechanism is effective only in the case of thin ferrihydrite-like nanostructures coordinated at the edge planes of the graphitic support, where nitrogen edge sites stabilize these species and lower the overpotential for the reaction. Larger ferrihydrite-like nanoparticles are ineffective for electron transport.

Recent advances in carbon-supported iron group electrocatalysts for the oxygen reduction reaction

Recent advances in carbon-supported iron group electrocatalysts for the oxygen reduction reaction

Fabrication of Bioresource-Derived Porous Carbon-Supported Iron as an Efficient Oxidase Mimic for Dual-Channel Biosensing.

Herein, we designed a new strategy for fabricating a renewable bioresource-derived N-doped hierarchical porous carbon-supported iron (Fe/NPC)-based oxidase mimic. The obtained results suggested that Fe/NPC possessed a large specific surface area (1144 m2/g) and pore volume (0.62 cm3/g) to afford extensive Fe-Nx active sites. Taking advantages of the remarkable oxidase-mimicking activity, outstanding stability, and reusability of Fe/NPC, a novel dual-channel biosensing system was strategically fabricated for sensitively determining acetylcholinesterase (AChE) through the integration of Fe/NPC and fluorescent silver nanoclusters (AgNCs) for the first time. The limits of detection for AChE can achieve as low as 0.0032 and 0.0073 U/L by the outputting fluorometric and colorimetric dual signals, respectively. Additionally, this dual-signal system was applied to analyze human erythrocyte AChE and its inhibitor with robust analytical performance. This work provides one sustainable and effective avenue to apply a bioresource for fabricating an Fe/NPC-based oxidase mimic with high catalytic performance and also gives new impetuses for developing novel biosensors by applying Fe/NPC-based enzyme mimics as substitutes for the natural enzyme.

A novel Fe/N/C electrocatalyst prepared from a carbon-supported iron(ii) complex of macrocyclic ligands for oxygen reduction reaction.

Herein, we report a novel method to synthesize Fe/N/C composites from a carbon-supported iron (ii) coordination complex of 2,3-dicyanotetraazabenzotriphenylene (2,3-DCTBT) ligands towards oxygen reduction reaction (ORR) in alkaline media. We investigated the influence of different temperatures during the thermal carbonization process on the performance of the catalyst, and Fe/N/C-900 stood out among all other samples because of the existence of Fe–Nx active sites. The as-obtained Fe/N/C-900 exhibited excellent electrochemical performance (Eonset is 0.98 V vs. RHE in 0.1 M KOH) for the oxygen reduction reaction (ORR) compared with the commercial 20% Pt/C. Moreover, this catalyst possessed good stability and high tolerance to methanol, and followed the four-electron mechanism (n = 3.97). Remarkably, the use of 2,3-DCTBT for the first time as a precursor has opened new avenues to prepare electrocatalysts for ORR.

Conversion of Xylose to Furfural over Lignin-Based Activated Carbon-Supported Iron Catalysts

In this study, conversion of xylose to furfural was studied using lignin-based activated carbon-supported iron catalysts. First, three activated carbon supports were prepared from hydrolysis lignin with different activation methods. The supports were modified with different metal precursors and metal concentrations into five iron catalysts. The prepared catalysts were studied in furfural production from xylose using different reaction temperatures and times. The best results were achieved with a 4 wt% iron-containing catalyst, 5Fe-ACs, which produced a 57% furfural yield, 92% xylose conversion and 65% reaction selectivity at 170 °C in 3 h. The amount of Fe in 5Fe-ACs was only 3.6 µmol and using this amount of homogeneous FeCl3 as a catalyst, reduced the furfural yield, xylose conversion and selectivity. Good catalytic activity of 5Fe-ACs could be associated with iron oxide and hydroxyl groups on the catalyst surface. Based on the recycling experiments, the prepared catalyst needs some improvements to increase its stability but it is a feasible alternative to homogeneous FeCl3.

Reduction of Nitroarenes Catalyzed by a Carbon-Supported Iron Catalyst

Reduction of Nitroarenes Catalyzed by a Carbon-Supported Iron Catalyst

Stability of carbon-supported iron catalysts for catalytic wet peroxide oxidation of ionic liquids

The stability of two carbon-supported Fe catalysts in the catalytic wet peroxide oxidation (CWPO) of 1-Butyl-3-methylimidazolium acetate (BmimAc) was examined. One catalyst (Fe/AS) was obtained by chemical activation of dried sewage sludge with iron chloride at a FeCl3:sewage sludge mass ratio of 3 and the other (Fe/HTCS) by hydrothermal carbonization of the sludge in the presence of FeCl3 at a mass ratio of also 3. Fe/AS catalyst exhibited a well-developed porosity, whereas Fe/HTCS one did not show porosity. The carbon content was high in both catalysts, with a total Fe content of 5.2 and 6.6% (w/w) for Fe/AS and Fe/HTCS catalysts, respectively. An aditional Fe catalyst prepared by incipient wetness impregnation on a commercial active carbon support (Fe/AC) was used for comparison with the previous two. All catalysts were active in experiments of H2O2 decomposition and long-term CWPO runs (0.133 kgFe h molBmimAc–1 at 80 °C). Whereas Fe/AC catalyst lost activity largely due to Fe leaching (90% of FeBulk), Fe/AS and Fe/HTCS catalysts exhibited virtually no Fe leaching and hence fairly good stability. Fe/AS catalyst, which afforded complete removal of Bmim+ and TOC conversion values around 30%, proved the most efficient catalyst.

Carbon-Supported Iron Phosphides: Highest Intrinsic Oxygen Evolution Activity of the Iron Triad

We compared the oxygen evolution reaction (OER) activity of carbon-supported iron triad metal phosphide nanoparticles using Fe-purified KOH electrolyte. We prepared these catalysts with nearly identical structural properties using an ammonia-assisted ambient hydrolysis deposition (AHD) method allowing us to explore how their compositions affect their OER activities. We discovered that iron phosphide is far superior to its counterparts with an onset potential lower by 150 mV. Furthermore, we found that the anodic voltammetric scan with associated oxidation of Fe(II) in the phosphide generates OER active sites; however, ambient oxidation of iron phosphide prior to that anodic scan deactivates the catalyst.

Carbon-supported iron complexes as electrocatalysts for the cogeneration of hydroxylamine and electricity in a NO-H2 fuel cell: A combined electrochemical and density functional theory study

Carbon-supported iron complexes were investigated as electrocatalysts for the reduction of nitric oxide (NO) in a H2-NO fuel cell conceived for the production of hydroxylamine (NH2OH) with concomitant generation of electricity. Two types of iron complexes with tetradentate ligands, namely bis(salicylidene)ethylenediimine (Salen) and phthalocyanine (Pc), supported on activated carbon or graphite were prepared and evaluated as electrocatalysts, either without further treatment or after pyrolysis at 700 °C. The performance in the reduction of NO of gas diffusion cathodes based on these electrocatalysts was investigated in an electrochemical half cell (3-electrode configuration) using linear sweep voltammetry (LSV). The most promising electrocatalysts were studied further by chronoamperometric experiments in a H2-NO fuel cell, which allowed comparison in terms of power output and hydroxylamine production. Depending on the concentration of the NO feed (6 or 18%), the best electrocatalytic performance was delivered either by FePc or FeSalen. The gas diffusion electrode based on FeSalen supported on activated carbon with 0.3 wt% Fe-loading provided the highest current density (86 A/m2) and the best current efficiency (43%) towards the desired NH2OH when operating at the higher NO concentration (18%). Moreover, FeSalen offers the advantage of being cheaper than FePc. The experimental work was complemented by density functional theory (DFT) calculations, which allowed to shed more light on the reaction mechanism for the reduction of nitric oxide at the atomistic level.