Carbonaceous Catalyst Research Articles

Solid waste-derived carbonaceous catalysts for environmental and energy applications

AbstractUrbanization and industrialization generate vast amounts of solid waste, posing significant threats to the biotic and abiotic components of the environment. Solid wastes-derived carbonaceous catalysts (SW-CCs) represent an effective strategy for resource utilization, and SW-CCs are gradually applied in environmental remediation and energy fields. However, the effects of the properties of SW-CCs on their catalytic activity remain inadequately understood. A comprehensive review of the applications of SW-CCs in environmental remediation and energy fields is yet to be achieved. It is necessary to systematically review the latest research progress of SW-CCs in environmental remediation and energy fields. First of all, this review summarizes the influences of various factors on the properties of SW-CCs and how these properties affect the catalytic activity. Subsequently, it explores the recent research progress and existing issues in the applications of SW-CCs in environmental remediation (persulfate activation, photocatalysis, and Fenton-like oxidation) and the energy sector (H2 production, biodiesel production, and CO2 conversion). Finally, future research prospects and recommendations are provided to facilitate further development and application of SW-CCs. This review offers new insights into the resource utilization of solid waste and the development of efficient and practical carbonaceous catalysts. Graphical Abstract

Carbonaceous Catalyst Boosting Conversion Kinetics of Na2S in Na-ion Batteries

Carbonaceous Catalyst Boosting Conversion Kinetics of Na2S in Na-ion Batteries

Balanced adsorption and oxidation in a porous P, N-doped carbon prepared by melt-salt-mediated strategy for enhanced fenton-like reaction

The activation of persulfate oxidation processes using carbon-based catalysts is attractive for eliminating persistent aromatic organic pollutants in wastewater treatment. Herein, N and P co-doped carbonaceous (NPC) catalysts with an ultrahigh surface area were synthesized using a melt-salt-mediated strategy, employing Zeolitic Imidazolate Framework-8 as a self-sacrificing template. The NPC(1:1) carbon, prepared under optimized conditions, exhibited the highest surface area of 2001.5 m2/g, characterized by the highest number of defects and a high dispersion of N (1.89 %) and P (0.30 %) atoms on the carbon. This carbon catalyst exhibited a high capacity for adsorption and potential for activating persulfates in the removal of p-Nitrophenol (p-NP). Experimental data indicate a balance between adsorption and oxidation in the NPC(1:1)/PDS/p-NP system, with the highest catalytic removal rate achieved through moderate pre-adsorption of p-NP. Evidence from quenching, electron paramagnetic resonance (EPR), and amperometric i-t experiments suggests that the NPC(1:1)/PDS system primarily degrades p-NP through an electron transfer pathway. Defects in carbon and graphitic N were identified as catalytic sites. These defects resulted in an electron-deficient state, which leads to the activation of PDS and graphitic N was more reactive than both pyridinic and pyrrolic N in the adsorption of PDS molecules. Additionally, P-containing groups such as C-P-O, C-O-P, and C3-P were pinpointed as active sites on the carbons through DFT calculations. The intermediates during p-NP degradation were identified, and possible degradation pathways were proposed. A toxicity analysis indicated a significant reduction in overall toxicity following the oxidation treatment. This study provides innovative insights into the balance between adsorption and catalytic activity in porous carbon-activated persulfate oxidation reactions, thereby aiding in the development of enhanced oxidation catalysts for environmental remediation.

Minimizing liquid/solid interfacial energy boosts Fe−N doping inside hollow carbon sphere for oxygen reduction in membrane-less direct formate fuel cell

Porous hollow carbon sphere (HCS) is an attractive catalyst support for oxygen reduction reaction (ORR) due to its large specific surface area for active site anchoring, porous and hollow structure for active site exposure and mass transfer. However, due to the high transfer resistance for exogenous heteroatoms into HCS, most of active sites are usually loaded on the outer surface of HCS, leading to the decrease of active site density and the aggregation of heteroatomic particles. In this work, we proposed that accompanied with the decrease of liquid/solid interfacial energy by changing solvent composition during impregnation, penetration of exogenous heteroatoms-containing solution was facilitated in HCS, resulting in increased density of uniformly-dispersed Fe−Nx active site by 58 %. Taking advantage of high-content and well-dispersed active site, structure-derived porosity for ion transfer and active site exposure, this HCS-derived catalyst (Fe-HCS@C2H5OH) exhibited positive onset and half-wave potentials of 0.953 V and 0.901 V (vs. RHE), as well as high power density of 20.17 ± 0.31 mW cm−2 when applied in membrane-less direct formate fuel cell cathode, surpassing those of commercial Pt/C and the state-of-the-art carbonaceous catalysts. This strategy of interfacial energy control provides a new stepping-stone for the synthesis of high-performance electrocatalysts.

Enhanced prednisone removal by catalytic wet air oxidation using sewage sludge derived catalyst

Sewage sludge-based catalysts have been used for the first time for the catalytic wet air oxidation (CWAO) of prednisone, a glucocorticoid pharmaceutical pollutant present in various aquatic environmental matrices. This research focuses on transforming dry sludge into carbonaceous catalysts through pyrolysis and post-treatment. Various parameters have been considered for the synthesis, finding that pyrolysis temperature and acid washing are determinant for specific surface area development. The sewage sludge derived catalysts exhibit high catalytic activity in the CWAO of prednisone (Dcat= 0.3 g·L−1, T= 100 °C, P= 15 bar). The development of porosity enhances their catalytic properties, the C-750-N catalysts demonstrated the highest activity for prednisone with 66 % TOC reduction, initial reaction rate 0.0092 mg·s−1 and 66 % CO2 selectivity. The study provides valuable insights into the synthesis, characterization, and application of sewage sludge-derived catalysts, offering a sustainable solution for wastewater treatment and pharmaceutical pollutant removal. Our present study indicates that catalysts with unique reforming properties may be potentially applicable for prednisone treatment and industrial applications.

Extraction and Depolymerization of Lignin from Different Agricultural and Forestry Wastes to Obtain Building Blocks in a Circular Economy Framework.

Large amounts of agri-food waste are generated and discarded annually, but they have the potential to become highly profitable sources of value-added compounds. Many of these are lignin-rich residues. Lignin, one of the most abundant biopolymers in nature, offers numerous possibilities as a raw material or renewable resource for the production of chemical products. This study aims to explore the potential revalorization of agricultural by-products through the extraction of lignin and subsequent depolymerization. Different residues were studied; river cane, rice husks, broccoli stems, wheat straw, and olive stone are investigated (all local wastes that are typically incinerated). Traditional soda extraction, enhanced by ultrasound, is applied, comparing two different sonication methods. The extraction yields from different residues were as follows: river cane (28.21%), rice husks (24.27%), broccoli (6.48%), wheat straw (17.66%), and olive stones (24.29%). Once lignin is extracted, depolymerization is performed by three different methods: high-pressure reactor, ultrasound-assisted solvent depolymerization, and microwave solvolysis. As a result, a new microwave depolymerization method has been developed and patented, using for the first time graphene nanoplatelets (GNPs) as new promising carbonaceous catalyst, achieving a 90.89% depolymerization rate of river cane lignin and yielding several building blocks, including guaiacol, vanillin, ferulic acid, or acetovanillone.

High-efficient microwave-assisted conversion of fructose to 5-hydroxymethylfurfural over rice straw-derived sulfonated porous carbonaceous catalyst

5-Hydroxymethylfurfural (HMF) has emerged as a pivotal platform chemical derived from biomass, attracting considerable attention for its renewable applications. In this study, sulfonated rice straw biochar (RSBC-SA) catalysts were developed and employed for microwave-assisted catalytic conversion of fructose to HMF. The RSBC-SA catalysts, synthesized by pyrolyzing rice straw biomass at different temperatures and subsequent functionalization with sulfonic acid groups, were characterized using X-ray photoelectron spectroscopy (XPS), elemental analysis, temperature programmed desorption (TPD) and Fourier-transform infrared spectroscopy (FT-IR). A comparative analysis of catalytic performance between microwave irradiation and conventional oil bath heating revealed a substantial enhancement in efficiency with the former. Notably, the 700 ℃ pyrolyzed RSBC-SA catalyst demonstrated the highest HMF yield of 92.6 % within just 5 min of reaction time under a microwavehydrothermal condition, surpassing the conventional oil bath heating method. In addition, moderate to high yields of HMF were achieved from different carbohydrates in our developed microwave reaction system, demonstrating significant catalytic activity. This superior catalytic effect under microwave irradiation can be attributed to the responsive dipole polarization of sulfonic acid groups, selective heating of the RSBC carrier via microwave absorption, and synergistic interactions among these factors. Overall, this study highlights the innovative use of agricultural waste and introduces a new method for creating microwave-responsive catalysts with biochar. This strategy enables efficient fructose conversion to HMF, promotes sustainable biomass transformation, and offers value-added uses for agricultural residues in chemical production.

Rational design of waste anode graphite-derived carbon catalyst to activate peroxymonosulfate for atrazine degradation

As the rapidly growing number of waste lithium-ion batteries (LIBs), the recycling and reutilization of anode graphite is of increasing interest. Converting waste anode graphite into functional materials may be a sensible option. Herein, a series of carbonaceous catalysts (TG) were successfully prepared using spent anode graphite calcined at various temperatures and applied for activating peroxymonosulfate (PMS) to degrade atrazine (ATZ). The catalyst obtained at 800 °C (TG-800) showed the optimum performance for ATZ removal (99.2% in 6 min). Various experimental conditions were explored to achieve the optimum efficiency of the system. In the TG-800/PMS system, free radicals (e.g., SO4·−, HO·), singlet oxygen (1O2), together with a direct electron transfer pathway all participated in ATZ degradation, and the ketonic (CO) group was proved as the leading catalytic site for PMS activation. The potential degradation routes of ATZ have also been presented. According to the toxicity assessment experiments, the toxicity of the intermediate products decreased. The reusability and universal applicability of the TG-800 were also confirmed. This research not only provides an efficient PMS activator for pollutant degradation, but also offers a meaningful reference for the recovery of waste anode graphite to develop environmentally functional materials.

Molecular-Level Tuning of Active Sites of the Carbonaceous Catalyst for Boosting Electrochemical H2O2 Production and its Application in Electro-Fenton-like Degradation of Organics

Molecular-Level Tuning of Active Sites of the Carbonaceous Catalyst for Boosting Electrochemical H₂O₂ Production and its Application in Electro-Fenton-like Degradation of Organics

Ferric sludge derived pyrolyzed-hydrochar supported iron catalysts for catalytic cracking of toluene

Effective treatment of ferric sludge in an eco-friendly method is key to the feasibility of Fenton technology in pollution treatment, contributing to the realization of the “dual-carbon” strategic objectives. In this study, Fe-loaded pyrolyzed-hydrochar catalysts were prepared using simple one-pot hydrothermal carbonization (HTC) method with ferric sludge as the precursor, which greatly reduced the energy and time consumption on the preparation of the sludge derived catalyst. At 800 °C with a reaction time of 20 min, all catalysts showed high toluene removal performance (>60 %) and produced H2-rich syngas (H2 > 90 %). In particular, the catalyst prepared by HNO3-assisted HTC (HNC) presented the highest toluene removal efficiency and H2 yield, 77.52 ± 3.36 % and 11.12 ± 0.66 mol%, respectively. Additionally, the sources of carbon deposits and the interaction between the active site and carbon deposits were analyzed in detail by DFT to reveal the catalytic activity and deactivation mechanism of catalyst. The results showed that the adsorption energy of C generated from methyl on different Fe phases was lowest (the adsorption energy of C was −8.79 eV for Fe, −5.28 eV for Fe2O3, and −4.70 eV for Fe3O4), suggesting that the adsorption of C on catalyst was the main reason for the formation of carbon deposits. The lowest adsorption energy of the metallic Fe phase for C indicated that Fe0 was coated by carbon deposits during toluene catalytic cracking, which hampered catalytic activity. These results are of great significance for optimizing the preparation of Fe-loaded carbonaceous catalysts and the regulation of Fe active phase.

Carbonaceous catalysts (biochar and activated carbon) from agricultural residues and their application in production of biodiesel: A review

Carbonaceous catalysts obtained from agricultural residue could have potential in the production of biofuels such as biodiesel. This review paper discusses the preparation conditions (temperature, heating rate, hold time, inert gas flow rate, etc play key roles in development of textural characteristics of the catalysts) and functionalization methods of biochar and activated carbon derived from agricultural residues and their application to produce biodiesel. Research works reported in achieving maximum yield of biodiesel in terms of variable precursors, alcohol-to-oil ratio, reaction time and temperatures have been profoundly tabulated. Effect of textural properties of the biochar and activated carbon (such as surface area, total pore volume, average pore size, and functional group attached with the catalyst) on the biodiesel yield are examined. Studies on Regeneration and reusing of the spent catalysts are carefully inspected. The economic evaluation studies for the biochar and activated carbon and the applications of these for biodiesel production are scrutinized. Finally, the strategies to increase biomass and catalyst productivity, future prospect and research directions to enhance biofuel/biodiesel production and for the development of biochar and activated carbon from agricultural residues for sustainable biodiesel production is suggested.

Microalgal synthesis of the biodiesel employing simultaneous extraction and esterification via heterogeneous catalyst

Within the realm of biorefinery, the third generation of biodiesel production relies on extracting oil from Algae to create renewable fuels. Algae cultivation can occur under precise laboratory conditions, making them a sustainable substitute for Fatty Acid Methyl Ester or biodiesel production. Through analysis of the simultaneous extraction and (trans)esterification process of Algae Chlorella Minutissima utilizing sulfated carbonaceous catalysts, scientists have discovered an efficient technique for producing biodiesel. Various parameters, such as catalyst loading, oil-to-methanol ratio, reaction temperature, and reaction time for FFA reduction and FAME yields, were studied and optimized. Results indicate that utilizing a 10 wt% catalyst loading and a 70:30 volumetric oil to methanol ratio can achieve 67.59 % FFA reduction and a biodiesel yield of 44 mL. This method of producing biodiesel can occur in a single-unit operation, leading to higher yields of renewable fuel at a reduced cost and energy consumption. Finally, the quality of the biodiesel produced met ASTM D6751 standards, confirming its suitability for use.

Facile tuning Non-radical/Radical oxidation by nitrogen doping on Fe-S doped carbonaceous catalysts for peroxymonosulfate activation

In this paper, iron-sulfur-nitrogen co-doped carbonaceous materials (Fe@SxNyC) was prepared by doping N during the preparation of iron-sulfur co-doped carbonaceous material (Fe@SC), which was used to activate PMS and effectively modulate the radical and non-radical oxidation pathways in the catalytic system to achieve efficient degradation of sulfamerazine (SMR). N doping introduced multiple N sites (graphitic N, pyridinic N and pyrrolic N) in the Fe@SxNyC while promoting the generation of thiophene sulfur of the pristine active sites. Meanwhile, N doping introduced more defects in Fe@S4NC and thus exhibited better catalytic activity than Fe@SC, promoting the decomposition of PMS with a maximum k value (0.1721 min−1). Notably, the involvement of nitrogen shifted the cooperative oxidation reaction from a non-radical (1O2) to a radical-dominated (SO4·–) oxidation pathway with more oxidative intensity, resulting in deeper mineralization of organic pollutants. Moreover, compared with Fe@SC/PMS system, the radical-dominated Fe@S4NC/PMS system had better cycling stability, and the efficiency of SMR degradation could still reach 85 % after 4 cycles. The prepared Fe@S4NC catalytic ceramic membrane exhibited stable water flux and exceptional catalytic activity, demonstrating that Fe@S4NC had good potential for practical applications. This work elucidated the improvement of the catalytic mechanism of iron-carbon based materials by doping with various heteroatoms and provided a theoretical basis to design Fenton-like heterogeneous catalysts suitable for different water matrix.

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Optimization of Catalytic Pyrolysis Process of Waste Cooking Oil with a Low-Cost Carbonaceous Catalyst Using Central Composite Design of Response Surface Methodology

Highly efficient and straightforward conversion of sugarcane bagasse into high value-added chemicals using carbonaceous catalyst in deep eutectic solvent

The conversion of biomass to 5-hydroxymethylfurfural (HMF), 2,5-diformylfuran (DFF), levulinic acid (LA), formic acid (FA), and other platform chemicals is attracting more attention. In this work, the catalysts were prepared from sugarcane bagasse with H2SO4 (BG-H2SO4) and with p-TsOH (BG-TsOH) containing –SO3H, –COOH, and –OH groups on the surface and used for the conversion of sugarcane bagasse into these valuable compounds. The cellulose was extracted from the sugarcane bagasse by an acetate-based ionic liquid and used as a starting material for this conversion. After investigation, the optimal conditions were BG-H2SO4 (50 mg), MnCl2.4H2O (1 mmol), and [DMSO][ChCl] deep eutectic solvent (10 mmol) at 120 °C for 10 h. The highest yields of valuable products were 17.59 % of HMF, 15.92 % of DFF, 20.02 % of FA, and 41.09 % of LA. Catalytic performance was compared to traditional methods using sulfuric acid in dimethyl sulfoxide (DMSO) or 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid. The BG-H2SO4 catalyst could be recovered and reused four times. Based on the study, the combination of BG-H2SO4, MnCl2.4H2O, and [DMSO][ChCl] demonstrated an efficient and sustainable reaction medium for biomass conversion. Our work will help the scientific community apply revolutionary technologies to sustainably create sophisticated materials with high technological application.

High Lewis acidity catalyst for direct depolymerization of microcrystalline cellulose to 5- hydroxymethylfurfural: Reaction optimization by central composite design

In direct conversion process of cellulose to 5-hydroxymethylfurfural (5-HMF), undesirable degradation inevitably occurs in the presence of Brønsted acid. Here, a carbonaceous catalyst was synthesized by grafting phosphotungstic acid to directly depolymerize microcrystalline cellulose (MCC) to 5-HMF. This catalyst exhibits high Lewis acidity (43.10 μmol g⁻1) and low Brønsted acidity (4.15 μmol g⁻1) with pyridine as reference compound. To comprehensively analyze the factors affecting MCC depolymerization, central composite design and response surface methodology techniques, incorporating variables such as reaction time, reaction temperature, catalyst dosage and MCC dosage. The highest yield of 5-HMF, 5.88 %, was obtained after 4.90 h at 171 °C using 45 mg of catalyst and 50 mg of MCC in biphasic system consisting of 1-butyl-3-methylimidazole chloride ([BMIM]Cl) and 2-sec-butylphenol. The catalyst was easily recovered and reused five times without a significant loss of catalytic activity. This work highlights the promise of efficient biomass refining by synergizing catalysts with high Lewis acidity and low Brønsted acidity in the biphasic system.

Hydrolysis of Fruit Waste to Reduce Sugars Using Sulphonated Magnetic Carbonaceous Catalyst

The sulphonated magnetic carbonaceous catalyst (Fe3O4@AC-SO3H) was effectively synthesised by functionalising the sulphonic acid group (–SO3H) on the surface of the core-shell structure of magnetic nanoparticle grafted activated carbon and analysed by SEM, XRD, and FT-IR. The As-prepared catalyst may aggressively hydrolyse biomass to sugar in a shorter reaction time. Hydrolysis factors such as catalyst dose, reaction temperature, and duration all had a significant impact on the hydrolysis of pomegranate peel waste. The catalyst could liberate 46% of TRS in 2 hours at 140°C from acid-pretreated pomegranate peel waste. This catalyst can be easily regenerated using a magnet and reused for up to three cycles with improved stability.

Trinity strategy prepared high-performance biochar for peroxydisulfate activation to degrade tetracycline

In this study, a novel high-performance biochar (BNC) was prepared using a trinity strategy of liquid templates, B/N co-doping, and one-step pyrolysis for activating peroxydisulfate (PDS) to degrade tetracycline (TC). The catalytic activity of BNC can be tuned by varying the boron doping ratio and pyrolysis temperature. Of these, the optimized product, BNC-2–900, degraded 80 % of TC (50 mg/L) in 30 min. The high degradation efficiency was attributed to the accelerated electron transfer originated by graphite N, CO, and B-N-C functional groups of BNC, in which the non-radical pathways containing electronic transfer and 1O2-mediated oxidation were indicated as the primary pathways for TC degradation. Furthermore, Box-Behnken design (BBD) was employed to optimize various operating parameters in the BNC/PDS system whereby optimal degradation conditions were determined: Initial TC concentration was 20 mg/L; PDS dosage was 64.57 mg; BNC dosage was 70.91 mg; Temperature was 50 °C; Initial pH was 8.3, where the TC degradation rate reached 100 %. This study provides a novel trinity strategy that combines stability, environmental friendliness, and facility for developing heteroatom-doped carbonaceous catalysts.