Tamara Lazarević-Pašti, Ana Jocić, Vedran Milanković, Tamara Tasić, Katarina Batalović, Stefan Breitenbach, Christoph Unterweger, Christian Fürst, Igor A. Pašti
In light of the escalating environmental concerns regarding pesticide accumulation, it is imperative to devise efficient strategies for their removal. Among the various options, activated carbons have emerged as promising candidates for adsorptive pesticide removal due to their many advantages, such as large surface area, well-developed porosity, and cost-effectiveness. However, the intricate relationship between the properties of these materials and their performance in pesticide adsorption remains largely unexplored. This study primarily focuses on examining the adsorption kinetics of three organophosphate pesticides: dimethoate, malathion (aliphatic), and chlorpyrifos (aromatic), using a range of cellulose-based activated carbon fibers with diverse specific surface areas, pore size distributions, and elemental compositions. By employing sophisticated data analysis tools, principal component analysis, and semi-empirical quantum chemical calculations, this study uncovers the importance of these distinct properties in efficiently removing structurally diverse pesticides. The results of the adsorption experiments suggested that these processes can be described using a pseudo-second-order kinetic model, which is confirmed via multiple linear regression. The obtained data suggest that the most effective carbon material for pesticide removal should have a pore diameter of approximately 4 nm, low oxygen content, a unimodal pore size distribution, and a high presence of sp2 domains. The insights from this research have the potential to guide the development of improved adsorbents and facilitate the rational selection of adsorbents tailored to specific pollutants based on their physicochemical properties and the pollutants’ chemical structure. By shedding light on the vital connection between adsorbent properties and performance, our findings significantly advance sustainable and effective pesticide removal, thereby fostering a cleaner and healthier environment.
{"title":"Investigating the Adsorption Kinetics of Dimethoate, Malathion and Chlorpyrifos on Cellulose-Derived Activated Carbons: Understanding the Influence of Physicochemical Properties","authors":"Tamara Lazarević-Pašti, Ana Jocić, Vedran Milanković, Tamara Tasić, Katarina Batalović, Stefan Breitenbach, Christoph Unterweger, Christian Fürst, Igor A. Pašti","doi":"10.3390/c9040103","DOIUrl":"https://doi.org/10.3390/c9040103","url":null,"abstract":"In light of the escalating environmental concerns regarding pesticide accumulation, it is imperative to devise efficient strategies for their removal. Among the various options, activated carbons have emerged as promising candidates for adsorptive pesticide removal due to their many advantages, such as large surface area, well-developed porosity, and cost-effectiveness. However, the intricate relationship between the properties of these materials and their performance in pesticide adsorption remains largely unexplored. This study primarily focuses on examining the adsorption kinetics of three organophosphate pesticides: dimethoate, malathion (aliphatic), and chlorpyrifos (aromatic), using a range of cellulose-based activated carbon fibers with diverse specific surface areas, pore size distributions, and elemental compositions. By employing sophisticated data analysis tools, principal component analysis, and semi-empirical quantum chemical calculations, this study uncovers the importance of these distinct properties in efficiently removing structurally diverse pesticides. The results of the adsorption experiments suggested that these processes can be described using a pseudo-second-order kinetic model, which is confirmed via multiple linear regression. The obtained data suggest that the most effective carbon material for pesticide removal should have a pore diameter of approximately 4 nm, low oxygen content, a unimodal pore size distribution, and a high presence of sp2 domains. The insights from this research have the potential to guide the development of improved adsorbents and facilitate the rational selection of adsorbents tailored to specific pollutants based on their physicochemical properties and the pollutants’ chemical structure. By shedding light on the vital connection between adsorbent properties and performance, our findings significantly advance sustainable and effective pesticide removal, thereby fostering a cleaner and healthier environment.","PeriodicalId":9397,"journal":{"name":"C","volume":"5 27","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The well-interconnected ternary Ni–Co–O nanosheets were grown on silicon carbide microspheres/graphite composite (gra@SiC/Ni–Co–O) by optimizing the electrodeposition method. Silicon carbide microspheres/graphite composite (gra@SiC) serves as a conductive template for the growth of Ni–Co–O nanosheets to form a binder-free 3D well-designed hierarchical interconnected network between the Ni–Co–O nanosheets and SiC microspheres. The obtained gra@SiC/Ni–Co–O is proposed as a great capacitance performance for supercapacitors. Field emission scanning electron microscopy (FESEM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy, and electrochemical analysis were employed to investigate the morphology and structural and electrochemical characteristics. The synergistic effects of EDLC (SiC microspheres) and pseudo-capacitance (Ni–Co–O nanosheets) can effectively improve the supercapacitive performance. It is also worth mentioning that after electrochemical testing, the redox reaction of Ni–Co–O nanosheets greatly promoted the faradic pseudo-capacitance contribution, and silicon carbide microspheres/graphite composite contributed to the formation of a 3D interconnected network, improving the cycling stability during the charging/discharging processes.
{"title":"Synthesis and Characterization of Ni–Co–O Nanosheets on Silicon Carbide Microspheres/Graphite Composite for Supercapacitor Applications","authors":"Han-Wei Chang, Zong-Ying Tsai, Jia-Jun Ye, Kuo-Chuang Chiu, Tzu-Yu Liu, Yu-Chen Tsai","doi":"10.3390/c9040101","DOIUrl":"https://doi.org/10.3390/c9040101","url":null,"abstract":"The well-interconnected ternary Ni–Co–O nanosheets were grown on silicon carbide microspheres/graphite composite (gra@SiC/Ni–Co–O) by optimizing the electrodeposition method. Silicon carbide microspheres/graphite composite (gra@SiC) serves as a conductive template for the growth of Ni–Co–O nanosheets to form a binder-free 3D well-designed hierarchical interconnected network between the Ni–Co–O nanosheets and SiC microspheres. The obtained gra@SiC/Ni–Co–O is proposed as a great capacitance performance for supercapacitors. Field emission scanning electron microscopy (FESEM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy, and electrochemical analysis were employed to investigate the morphology and structural and electrochemical characteristics. The synergistic effects of EDLC (SiC microspheres) and pseudo-capacitance (Ni–Co–O nanosheets) can effectively improve the supercapacitive performance. It is also worth mentioning that after electrochemical testing, the redox reaction of Ni–Co–O nanosheets greatly promoted the faradic pseudo-capacitance contribution, and silicon carbide microspheres/graphite composite contributed to the formation of a 3D interconnected network, improving the cycling stability during the charging/discharging processes.","PeriodicalId":9397,"journal":{"name":"C","volume":"109 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136135245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Raúl Llamas-Unzueta, Luis A. Ramírez-Montoya, J. Angel Menéndez, Miguel A. Montes-Morán
Novel customised carbon monoliths with a high specific surface area were synthesised by carbonisation plus activation of dehydrated whey powders, a biomass byproduct of the dairy industry. The whey powders were casted directly by pouring them into a desired mould. After a pseudo-sintering process promoted by the self-reaction of the whey components (mostly lactose and whey proteins) at moderate temperatures (ca. 250 °C), 3D porous carbons were obtained. The process did not require any binder or external overpressure to prepare the 3D porous carbons. Upon thermal activation with CO2 or chemical activation with H3PO4 and KOH, the shape of the monolithic structure was preserved after the development of a microporous network (SBET up to 2400 m2/g). Both thermal and chemical activation had little effect on the macroporosity of the monoliths. Activation of these 3D carbons had to be performed with care to avoid heterogeneous skin/core activation and/or overactivation. Highly porous monoliths (SBET of 980 m2/g; open porosity of 70%) with outstanding compressive strength (10 MPa) could be obtained by thermal activation (CO2) of whey monoliths at 850 °C for 1.5 h. Additionally, the use of whey as a precursor provided the carbon monolith with a relatively high nitrogen content (ca. 3 wt.%).
{"title":"Customised Microporous Carbon 3D Structures with Good Mechanical Properties and High Nitrogen Content Obtained from Whey Powders","authors":"Raúl Llamas-Unzueta, Luis A. Ramírez-Montoya, J. Angel Menéndez, Miguel A. Montes-Morán","doi":"10.3390/c9040100","DOIUrl":"https://doi.org/10.3390/c9040100","url":null,"abstract":"Novel customised carbon monoliths with a high specific surface area were synthesised by carbonisation plus activation of dehydrated whey powders, a biomass byproduct of the dairy industry. The whey powders were casted directly by pouring them into a desired mould. After a pseudo-sintering process promoted by the self-reaction of the whey components (mostly lactose and whey proteins) at moderate temperatures (ca. 250 °C), 3D porous carbons were obtained. The process did not require any binder or external overpressure to prepare the 3D porous carbons. Upon thermal activation with CO2 or chemical activation with H3PO4 and KOH, the shape of the monolithic structure was preserved after the development of a microporous network (SBET up to 2400 m2/g). Both thermal and chemical activation had little effect on the macroporosity of the monoliths. Activation of these 3D carbons had to be performed with care to avoid heterogeneous skin/core activation and/or overactivation. Highly porous monoliths (SBET of 980 m2/g; open porosity of 70%) with outstanding compressive strength (10 MPa) could be obtained by thermal activation (CO2) of whey monoliths at 850 °C for 1.5 h. Additionally, the use of whey as a precursor provided the carbon monolith with a relatively high nitrogen content (ca. 3 wt.%).","PeriodicalId":9397,"journal":{"name":"C","volume":"45 5-6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiu Jin, Ziye Zheng, Yuxiao Feng, Shuang Tian, Zuoli He
Hexavalent chromium (Cr(VI)) compounds are considered to be occupational carcinogens, which can be transferred from the environment to the human body and pose a significant threat to human health. It is particularly urgent to explore a more efficient catalyst for removing Cr(VI) to comply with discharge standards. The addition of CNTs enables the separation and transfer of photogenerated charges. Thus, we synthesized a range of NiCo2S4 hybrid materials with different multi-walled carbon nanotube (MWCNTs) contents using a two-step hydrothermal method. The composites had significant advantages compared to pure NiCo2S4, such as an enhanced visible light absorption, increased specific surface area, high electron–hole pair separation, and fast electron transport. Thus, MWCNT addition enabled efficient photocatalytic performances in terms of reducing hexavalent chromium (Cr(VI)). Among all the composite samples, the MWCNT/NiCo2S4 with 0.050 g of MWCNTs achieved the highest efficiency in reducing Cr(VI) under light irradiation, which showed a removal rate close to 100% within 40 min. Such CNT-based composite photocatalysts could be used to reduce the highly toxic Cr(VI) in environmental applications.
{"title":"Multi-Walled Carbon Nanotubes Modified NiCo2S4 for the Efficient Photocatalytic Reduction of Hexavalent Chromium","authors":"Qiu Jin, Ziye Zheng, Yuxiao Feng, Shuang Tian, Zuoli He","doi":"10.3390/c9040099","DOIUrl":"https://doi.org/10.3390/c9040099","url":null,"abstract":"Hexavalent chromium (Cr(VI)) compounds are considered to be occupational carcinogens, which can be transferred from the environment to the human body and pose a significant threat to human health. It is particularly urgent to explore a more efficient catalyst for removing Cr(VI) to comply with discharge standards. The addition of CNTs enables the separation and transfer of photogenerated charges. Thus, we synthesized a range of NiCo2S4 hybrid materials with different multi-walled carbon nanotube (MWCNTs) contents using a two-step hydrothermal method. The composites had significant advantages compared to pure NiCo2S4, such as an enhanced visible light absorption, increased specific surface area, high electron–hole pair separation, and fast electron transport. Thus, MWCNT addition enabled efficient photocatalytic performances in terms of reducing hexavalent chromium (Cr(VI)). Among all the composite samples, the MWCNT/NiCo2S4 with 0.050 g of MWCNTs achieved the highest efficiency in reducing Cr(VI) under light irradiation, which showed a removal rate close to 100% within 40 min. Such CNT-based composite photocatalysts could be used to reduce the highly toxic Cr(VI) in environmental applications.","PeriodicalId":9397,"journal":{"name":"C","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna M. Ozerova, Elena S. Tayban, Inna L. Lipatnikova, Arina R. Potylitsyna, Yury I. Bauman, Igor P. Prosvirin, Yury V. Shubin, Aleksey A. Vedyagin, Ilya V. Mishakov, Olga V. Netskina
In this study, carbon nanofibers were synthesized by the catalytic pyrolysis of trichloroethylene (CNF-Cl) and its mixture with acetonitrile (CNF-Cl-N). The addition of acetonitrile resulted in the incorporation of nitrogen in the CNF (0.33 at%), the removal of chlorine, an increase in oxygen-containing functional groups on the surface (from 1.6 to 3.6 at%), and an increase in the volume of mesopores (from 0.35 to 0.41 cm3·g−1) and macropores (from 0.115 to 0.393 cm3·g−1). The study of 2,4-DCBA adsorption on both CNFs revealed that the adsorption capacity showed dependence with a maximum on the 2,4-DCBA concentration in the solution, which was attributed to the electrostatic interactions of adsorbate with adsorbent at various pHs. The adsorption forces were effective over distances greater than the size of the 2,4-DCBA molecule, indicating volume pore filling. The maximum adsorption capacity occurred at 0.7–1.2 mM and a pH of 3.4 ± 0.1. CNF-Cl-N exhibited lower 2,4-DCBA adsorption than CNF-Cl-N due to its lower specific surface area, lower micropore volume, and higher concentration of oxygen-containing groups on the surface. However, these differences were not significant, suggesting that CNFs produced from both chlorine-containing wastes and their mixtures with nitrogen-containing compounds can be effectively used for water treatment to remove 2,4-DCBA.
{"title":"The Adsorption of 2,4-Dichlorobenzoic Acid on Carbon Nanofibers Produced by Catalytic Pyrolysis of Trichloroethylene and Acetonitrile","authors":"Anna M. Ozerova, Elena S. Tayban, Inna L. Lipatnikova, Arina R. Potylitsyna, Yury I. Bauman, Igor P. Prosvirin, Yury V. Shubin, Aleksey A. Vedyagin, Ilya V. Mishakov, Olga V. Netskina","doi":"10.3390/c9040098","DOIUrl":"https://doi.org/10.3390/c9040098","url":null,"abstract":"In this study, carbon nanofibers were synthesized by the catalytic pyrolysis of trichloroethylene (CNF-Cl) and its mixture with acetonitrile (CNF-Cl-N). The addition of acetonitrile resulted in the incorporation of nitrogen in the CNF (0.33 at%), the removal of chlorine, an increase in oxygen-containing functional groups on the surface (from 1.6 to 3.6 at%), and an increase in the volume of mesopores (from 0.35 to 0.41 cm3·g−1) and macropores (from 0.115 to 0.393 cm3·g−1). The study of 2,4-DCBA adsorption on both CNFs revealed that the adsorption capacity showed dependence with a maximum on the 2,4-DCBA concentration in the solution, which was attributed to the electrostatic interactions of adsorbate with adsorbent at various pHs. The adsorption forces were effective over distances greater than the size of the 2,4-DCBA molecule, indicating volume pore filling. The maximum adsorption capacity occurred at 0.7–1.2 mM and a pH of 3.4 ± 0.1. CNF-Cl-N exhibited lower 2,4-DCBA adsorption than CNF-Cl-N due to its lower specific surface area, lower micropore volume, and higher concentration of oxygen-containing groups on the surface. However, these differences were not significant, suggesting that CNFs produced from both chlorine-containing wastes and their mixtures with nitrogen-containing compounds can be effectively used for water treatment to remove 2,4-DCBA.","PeriodicalId":9397,"journal":{"name":"C","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136062694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bhavya Joshi, Ahmed M. E. Khalil, Shaowei Zhang, Fayyaz A. Memon
Pharmaceuticals have emerged as a new class of ecological pollutants and have majorly contributed to harmful effects on the environment and human health. The presence of these pharmaceuticals in wastewater treatment plants, ground, and seawater has been reported widely. Organic dyes and other organic contaminants which are being considered as emerging contaminants are now in the race among the top organic pollutants that need effective treatment. Removal of these contaminants via green adsorbents has become an essential requirement towards a green and cleaner environment. Herein, we report the efficacy of the novel greener porous graphene obtained via the near-green synthesis method as an adsorbent material for treating seven organic pollutants: Methyl orange, Methyl red, Rhodamine-B, Ciprofloxacin, Atenolol, Ibuprofen, and Carbamazepine. Batch tests were conducted to investigate the effect of adsorption time and varying adsorbent dosages. The obtained greener porous graphene showed fast kinetics, which was determined to be guided by pseudo second-order kinetics and the maximum pollutant removal efficiency (>80%) was seen at a high adsorbent dosage (2 mL injected from a 5 g/L solution). Furthermore, the nonlinear adsorption modeling confirmed that the greener porous graphene followed the Langmuir model for the dye rhodamine-B sorption and the Freundlich model for all the other six contaminants. This greener porous graphene can be considered an effective adsorbent for the removal of organic pollutants in wastewater.
{"title":"Investigating the Potential of Greener-Porous Graphene for the Treatment of Organic Pollutants in Wastewater","authors":"Bhavya Joshi, Ahmed M. E. Khalil, Shaowei Zhang, Fayyaz A. Memon","doi":"10.3390/c9040097","DOIUrl":"https://doi.org/10.3390/c9040097","url":null,"abstract":"Pharmaceuticals have emerged as a new class of ecological pollutants and have majorly contributed to harmful effects on the environment and human health. The presence of these pharmaceuticals in wastewater treatment plants, ground, and seawater has been reported widely. Organic dyes and other organic contaminants which are being considered as emerging contaminants are now in the race among the top organic pollutants that need effective treatment. Removal of these contaminants via green adsorbents has become an essential requirement towards a green and cleaner environment. Herein, we report the efficacy of the novel greener porous graphene obtained via the near-green synthesis method as an adsorbent material for treating seven organic pollutants: Methyl orange, Methyl red, Rhodamine-B, Ciprofloxacin, Atenolol, Ibuprofen, and Carbamazepine. Batch tests were conducted to investigate the effect of adsorption time and varying adsorbent dosages. The obtained greener porous graphene showed fast kinetics, which was determined to be guided by pseudo second-order kinetics and the maximum pollutant removal efficiency (>80%) was seen at a high adsorbent dosage (2 mL injected from a 5 g/L solution). Furthermore, the nonlinear adsorption modeling confirmed that the greener porous graphene followed the Langmuir model for the dye rhodamine-B sorption and the Freundlich model for all the other six contaminants. This greener porous graphene can be considered an effective adsorbent for the removal of organic pollutants in wastewater.","PeriodicalId":9397,"journal":{"name":"C","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135300762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julie Genoyer, Emna Helal, Giovanna Gutierrez, Nima Moghimian, Eric David, Nicole R. Demarquette
The effectiveness of layered particles as processing aid agents in molten polystyrene was studied. Three graphene grades and two clays of different lateral size were selected for this purpose. The morphologies of the composites were observed using scanning electron microscopy. Steady shear measurements were carried out and the Carreau–Yasuda model with yield stress was applied to the experimental results. A decrease in viscosity was observed at 2 wt.% of particle content for almost all composites. The most efficient particle for reducing viscosity was found to be graphene in a loose agglomerated configuration. Graphene and clay particles with similar dispersion states had a similar effect on the viscosity, inducing a decrease by 29% and 22%, respectively, suggesting comparable efficiency as processing aid agents. The observed decrease in viscosity is attributed to the phenomenon of superlubricity, which is a lubricating mechanism that is closely linked to the atomic structure of the particles.
{"title":"Graphene and Nanoclay as Processing Aid Agents: A Study on Rheological Behavior in Polystyrene","authors":"Julie Genoyer, Emna Helal, Giovanna Gutierrez, Nima Moghimian, Eric David, Nicole R. Demarquette","doi":"10.3390/c9040096","DOIUrl":"https://doi.org/10.3390/c9040096","url":null,"abstract":"The effectiveness of layered particles as processing aid agents in molten polystyrene was studied. Three graphene grades and two clays of different lateral size were selected for this purpose. The morphologies of the composites were observed using scanning electron microscopy. Steady shear measurements were carried out and the Carreau–Yasuda model with yield stress was applied to the experimental results. A decrease in viscosity was observed at 2 wt.% of particle content for almost all composites. The most efficient particle for reducing viscosity was found to be graphene in a loose agglomerated configuration. Graphene and clay particles with similar dispersion states had a similar effect on the viscosity, inducing a decrease by 29% and 22%, respectively, suggesting comparable efficiency as processing aid agents. The observed decrease in viscosity is attributed to the phenomenon of superlubricity, which is a lubricating mechanism that is closely linked to the atomic structure of the particles.","PeriodicalId":9397,"journal":{"name":"C","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135301112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ziyi Wan, Ping Tang, Luwei Dai, Yao Yang, Lu Li, Jun Liu, Min Yang, Guowei Deng
A reasonable design of nickel-based catalysts is key to efficient and sustainable energy conversion. For electrocatalytic materials in alkaline electrolytes, however, atomic-level control of the active sites is essential. Moreover, the well-defined surface structure contributes to a deeper understanding of the catalytic mechanism. Here, we report the loading of defective nickel–cobalt layered double hydroxide nanosheets (Ni2Co-LDH@C) after carbonization of silk. Under the precise regulation of the local coordination environment of the catalytic active site and the presence of defects, Ni2Co-LDH@C can provide an ultra-low overpotential of 164.8 mV for hydrogen evolution reactions (HERs) at 10 mA cm−2, exceeding that of commercial Pt/C catalysts. Density functional theory calculations show that Ni2Co-LDH@C optimizes the adsorption energy of the intermediate and promotes the O-O coupling of the active site in the oxygen evolution reaction. When using Ni2Co-LDH@Cs as cathodes and anodes to achieve overall water splitting, a low voltage of 1.63 V is required to achieve a current density of 10 mA cm−2. As an ideal model, Ni2Co-LDH@C has excellent water splitting properties and has the potential to develop water–alkali electrocatalysts.
合理设计镍基催化剂是实现高效、可持续能源转化的关键。然而，对于碱性电解质中的电催化材料，活性位点的原子水平控制是必不可少的。此外，明确的表面结构有助于更深入地了解催化机理。在这里，我们报道了在丝绸炭化后加载缺陷镍钴层状双氢氧化物纳米片(Ni2Co-LDH@C)。在催化活性位点局部配位环境的精确调控和缺陷的存在下，Ni2Co-LDH@C可以在10 mA cm−2下为析氢反应(HERs)提供164.8 mV的超低过电位，超过了商用Pt/C催化剂的过电位。密度泛函理论计算表明，Ni2Co-LDH@C优化了中间体的吸附能，促进了析氧反应中活性位点的O-O偶联。当使用Ni2Co-LDH@Cs作为阴极和阳极来实现整体的水分解时，需要1.63 V的低电压来实现10 mA cm−2的电流密度。Ni2Co-LDH@C作为一种理想模型，具有优异的水裂解性能，具有开发水碱电催化剂的潜力。
{"title":"Highly Effective Electrochemical Water Splitting with Enhanced Electron Transfer between Ni2Co Layered Double Hydroxide Nanosheets Dispersed on Carbon Substrate","authors":"Ziyi Wan, Ping Tang, Luwei Dai, Yao Yang, Lu Li, Jun Liu, Min Yang, Guowei Deng","doi":"10.3390/c9040094","DOIUrl":"https://doi.org/10.3390/c9040094","url":null,"abstract":"A reasonable design of nickel-based catalysts is key to efficient and sustainable energy conversion. For electrocatalytic materials in alkaline electrolytes, however, atomic-level control of the active sites is essential. Moreover, the well-defined surface structure contributes to a deeper understanding of the catalytic mechanism. Here, we report the loading of defective nickel–cobalt layered double hydroxide nanosheets (Ni2Co-LDH@C) after carbonization of silk. Under the precise regulation of the local coordination environment of the catalytic active site and the presence of defects, Ni2Co-LDH@C can provide an ultra-low overpotential of 164.8 mV for hydrogen evolution reactions (HERs) at 10 mA cm−2, exceeding that of commercial Pt/C catalysts. Density functional theory calculations show that Ni2Co-LDH@C optimizes the adsorption energy of the intermediate and promotes the O-O coupling of the active site in the oxygen evolution reaction. When using Ni2Co-LDH@Cs as cathodes and anodes to achieve overall water splitting, a low voltage of 1.63 V is required to achieve a current density of 10 mA cm−2. As an ideal model, Ni2Co-LDH@C has excellent water splitting properties and has the potential to develop water–alkali electrocatalysts.","PeriodicalId":9397,"journal":{"name":"C","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135695485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphene has gained significant attention since its discovery in 2004, and the modification of few-layer graphene provides a platform to tailor its physical and electronic properties. In this study, we employed unrestricted density functional theory (DFT) with the PBE+U functional to investigate the electronic and magnetic properties of FeCl3-intercalated bilayer graphene (BLG). Both in BLG and stage-2 intercalated graphite, a distinct localization of electrons on a specific Fe atom is evident, gaining approximately 0.245 electrons evaluated with Bader analysis, while the holes are delocalized within the graphene layers. This results in p-doped graphene, characterized by a shift of the Dirac cone by 0.74 eV for BLG and 0.70 eV for stage-2 intercalated graphite. Ferromagnetic ordering is observed within the plane of FeCl3-intercalated BLG, whereas the FeCl3 layers exhibit antiferromagnetic coupling in stage-2 intercalated graphite. The ferromagnetic nature and electronic structure of the FeCl3-intercalated BLG is retained under pressure.
{"title":"Electronic and Magnetic Properties of FeCl3 Intercalated Bilayer Graphene","authors":"Jiajun Dai, Shilpa Yadav, Beate Paulus","doi":"10.3390/c9040095","DOIUrl":"https://doi.org/10.3390/c9040095","url":null,"abstract":"Graphene has gained significant attention since its discovery in 2004, and the modification of few-layer graphene provides a platform to tailor its physical and electronic properties. In this study, we employed unrestricted density functional theory (DFT) with the PBE+U functional to investigate the electronic and magnetic properties of FeCl3-intercalated bilayer graphene (BLG). Both in BLG and stage-2 intercalated graphite, a distinct localization of electrons on a specific Fe atom is evident, gaining approximately 0.245 electrons evaluated with Bader analysis, while the holes are delocalized within the graphene layers. This results in p-doped graphene, characterized by a shift of the Dirac cone by 0.74 eV for BLG and 0.70 eV for stage-2 intercalated graphite. Ferromagnetic ordering is observed within the plane of FeCl3-intercalated BLG, whereas the FeCl3 layers exhibit antiferromagnetic coupling in stage-2 intercalated graphite. The ferromagnetic nature and electronic structure of the FeCl3-intercalated BLG is retained under pressure.","PeriodicalId":9397,"journal":{"name":"C","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135740092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this work is to study the properties of carbon materials prepared from apricot stones by carbonization at 300–900 °C and chemical activation by KOH with different ratios between components. It was found that increasing the carbonization temperature to 800–900 °C leads to the degradation of narrow micropores and the carbon matrix. The adsorbent materials were characterized with FTIR and SEM, and a specific surface area was calculated. Moreover, additional activation by HNO3 and annealing at 450 °C led to an increase in surface area up to 1300 m2/g. The obtained N-enriched sorbents show adsorption activities of 190–235 mg/g for methylene blue and 210–260 mg/g for methyl orange. The results of this study can be useful for future scale-up using the apricot material as a low-cost adsorbent for the removal of dyes in environmental remediation production.
{"title":"Chemical Activation of Apricot Pit-Derived Carbon Sorbents for the Effective Removal of Dyes in Environmental Remediation","authors":"Vitalii Vashchynskyi, Olena Okhay, Tetiana Boychuk","doi":"10.3390/c9040093","DOIUrl":"https://doi.org/10.3390/c9040093","url":null,"abstract":"The aim of this work is to study the properties of carbon materials prepared from apricot stones by carbonization at 300–900 °C and chemical activation by KOH with different ratios between components. It was found that increasing the carbonization temperature to 800–900 °C leads to the degradation of narrow micropores and the carbon matrix. The adsorbent materials were characterized with FTIR and SEM, and a specific surface area was calculated. Moreover, additional activation by HNO3 and annealing at 450 °C led to an increase in surface area up to 1300 m2/g. The obtained N-enriched sorbents show adsorption activities of 190–235 mg/g for methylene blue and 210–260 mg/g for methyl orange. The results of this study can be useful for future scale-up using the apricot material as a low-cost adsorbent for the removal of dyes in environmental remediation production.","PeriodicalId":9397,"journal":{"name":"C","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135293687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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