DALTON TRANSACTIONS
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2023
·Vol. 52
·期 14
·4389-4397
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IF 4
Yujun Wu,Wei Shuang,Lin Yang,Chuanbao Cao
Graphene-based materials have been regarded recently as a promising substance for electrochemical energy conversion and storage devices owing to their unique structure and extraordinary properties. Herein, an enormously facile one-step pyrolysis approach is reported for the fabrication of ternary (P,S,N)-doped graphene, which is further investigated as an efficient metal-free electrocatalyst for the oxygen reduction reaction (ORR). Furthermore, optimized ternary-doped graphene can deliver excellent ORR catalytic activity that favors the four-electron ORR process and outstanding long-term durability (90.54% current retention after 20000 s which is far superior to that of commercial Pt/C) owing to the preferable synergetic coupling effect between P, S and N. Density functional theory (DFT) calculations were performed to reveal the synergetic coupling effect between doping elements in the ORR process. This work provides an extremely simple one-step pyrolysis method for the synthesis of P,S,N-doped graphene for electrochemical energy conversion and storage devices.
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高影响因子
FUEL
·
2023
·
IF 7.4
Haipeng Liu,Haifeng Jiang,Jiaxing Song,Ling Zhang,Yu Zhang,Yuhang Li,Wenpeng Hong
The production of high value-added liquid products by catalytic pyrolysis of cellulose has become an effective way to realize the efficient utilization of biomass. This work synthesized a series of Co-Ce, Co-Fe and Co-Mg composite metal catalysts and used them to obtain furans and ketones production. In addition, the CO 2 was used as a pyrolysis atmosphere to investigate the synergistic effect between CO 2 and the prepared catalyst. The results showed that the catalyst effectively promoted the depolymerization of cellulose and improved the oxygen transfer behavior between volatile matters during cellulose pyrolysis. As a reaction medium, CO 2 influenced the carbon distribution of products, thereby increasing syngas yield, and the CO 2 atmosphere promoted the formation of furans and ketones. Compared with those obtained by the non-catalytic pyrolysis in N 2 atmosphere, the relative contents of furans and ketones in the liquid products produced by the catalytic pyrolysis of cellulose in CO 2 atmosphere increased by about 13.38% and 9.8%. In the CO 2 environment, the generation ability for furans was Co-Mg catalyst > Co-Ce catalyst > Co-Fe catalyst, and the generation ability for ketones was Co-Ce catalyst > Co-Mg catalyst > Co-Fe catalyst. These works provide an important way for the efficient preparation of furans and ketones from biomass pyrolysis.
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FUEL PROCESSING TECHNOLOGY
·
2023
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IF 7.5
Xiaohua Li,Haowen Fu,Shanshan Shao,Yixi Cai
Templating agents were created by utilizing several methods to handle natural cellulose (bagasse), and they were successfully used to treat HZSM-5 to introduce extra mesopores . In addition, the hierarchical HZSM-5 was employed in the catalytic pyrolysis of biomass to produce hydrocarbon fuels. The hydroxyl content in the templating agent could be promoted via hydrothermal and ultrasound-assisted treatment, improving their performance as templates to produce mesopores. The cellulose content in the templating agents was effectively boosted via hydrothermal-assisted treatment, whereas their relative crystallinity was improved by ultrasound assistance. The formation of mesopores was promoted with the increased cellulose content in the templating agents, and the catalytic performance in upgrading pyrolysis gas for aromatic hydrocarbons could be significantly improved. Higher relative crystallinity was advantageous for enhancing the stability of the templating agent in the catalyst synthesis system, and the formation of pore structures of the catalyst was promoted. Among all catalysts synthesized, catalysts synthesized by hydrothermal-assisted treatment (Cat-H(X)) presented the highest specific surface area and average pore size of 397.60 m 2 /g and 4.53 nm, which were about 1.41 and 1.98 times of commercial HZSM-5 (H-Z). The highest yield of BTX obtained with Cat-H(X) was 8.7 wt%, 1.81 times that obtained with H-Z.
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Journal of Cleaner Production
·
2022
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IF 11.072
Peng Li,Bo Niu,Helin Pan,Yayun Zhang,Donghui Long
The bio-oil produced by the catalytic pyrolysis of waste cooking oil (WCO) has great potential to become a substitute for fossil fuels. However, the low yield and high oxygen content of pyrolysis oil result in low added value. The low-cost production of high-yield and high-quality hydrocarbon-rich pyrolysis oil remains challenging. To efficiently convert WCO to high quality hydrocarbon-rich pyrolysis oil, a nickel oxide loaded activated carbon catalyst (Ni/AC) was introduced in the ex-situ catalytic system . The catalytic pyrolysis results showed that the catalyst exhibited high deoxygenation activity and the hydrocarbon content in the bio-oil could reach up to 99%. The selectivity of total aromatic hydrocarbons and monocyclic aromatic hydrocarbons in liquid oil could reach 86.38% and 68.47%, respectively. By extracting hydrogen from hydrocarbon fragment, the NiO site facilitates dehydrogenation , resulting in a gaseous product with syngas (CO, H 2 ) as the main component, with a maximum syngas concentration of 70%. The hydrogen produced is favorable for hydrogen transfer reactions and as a result promotes deoxygenation and hydrocarbon production. This study provides valuable insight into a low-cost, efficient, and high-value-added way to recover WCO. It will avoid the risk of environmental pollution caused by WCO and provide a reference for the sustainable use of waste.
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CHEMOSPHERE
·
2023
·
IF 8.8
Yuxiang Chen,Chao Li,Lijun Zhang,Qifeng Chen,Shu Zhang,Jun Xiang,Song Hu,Yi Wang,Xun Hu
The interaction between volatiles and homologous and/or heterologous char is almost inevitable during the transfer or diffusion of volatiles from inner core to outer surface of a biomass particle in pyrolysis . This shapes both composition of volatiles (bio-oil) and property of char. In this study, the potential interaction of lignin- and cellulose-derived volatiles with char of varied origin was investigated at 500 °C. The results indicated that both the lignin- and cellulose-char promoted polymerization of the lignin-derived phenolics, enhancing production of bio-oil by ca. 20%–30%, generating more heavy tar but suppressing gases formation, especially over cellulose-char. Conversely, the char catalysts, especially the heterologous lignin-char, promoted cracking of the cellulose-derivatives, producing more gases while less bio-oil and heavy organics. Additionally, the volatiles-char interaction also led to gasification of some organics and also aromatization of some organics on surface of char, resulting in enhanced crystallinity and thermostability of the used char catalyst, especially for the lignin-char. Moreover, the substance exchange and formation of carbon deposit also blocked pores and formed fragmented surface dotted with particulate matters in the used char catalysts.
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ACS Omega
·
2022
·
IF 4.132
Haiyu Meng,Mengzhuo Wang,Zhiqiang Wu,Jun Zhao,Jiake Li,Shuzhong Wang
Co-pyrolysis of waste plastics and coal has been considered to be an environmentally friendly and scalable waste treatment technology. This study investigated the influence of polyvinyl chloride (PVC) on the physico-chemical structure and gasification performance of co-pyrolytic char with lignite (PZ) and bituminous (SM) coal. The structure characteristics were explored by applying an X-ray diffractometer and a specific surface area analyzer. The quantitative analysis on the influence of PVC on pore characteristics and carbon microcrystal structure was conducted by the fractal theory and deconvolution method. The gasification performance was explored using a thermogravimetric analyzer. When the PZ blending ratio was larger than 50%, the specific surface area of PVCPZ chars enlarged significantly due to the increment of mesopores. Nevertheless, the effect of SM on the pore structure was not pronounced, and the specific surface area of PVCSM chars was as small as PVC char. A higher PZ blending ratio benefited the formation of mesopores with an aperture smaller than 10 nm for PVCPZ chars, whereas SM had little influence on pore diameter distributions of PVCSM chars attributed to the remarkable coating effects. The values of fractal dimension of co-pyrolytic char were larger than PVC char, revealing that the adjunction of coal increased the pore surface coarseness and improved the complicacy of the pore structure. Quantitative analysis on XRD spectra indicated that the disorder extent of the carbon structure was improved because of coal addition, and the influence of lignite on the disorder degree of the carbon structure was more significant. The gasification reaction of co-pyrolytic char showed significant synergistic effects, resulting in the improvement of gasification performance.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
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IF 24.319
Shizong Wang,Jianlong Wang
This study prepared the carbon-supported cobalt catalyst (Co-C-X) for activating peroxymonosulfate (PMS), and investigated the effect of co-pyrolysis temperature of graphitic carbon nitride (g-C 3 N 4 ) and vitamin B 12 on the catalytic activity. It was found that with the increase of co-pyrolysis temperature, the catalytic activity of Co-C-X increased, due to the different coordination structures of cobalt. At 500 °C (Co-C-500), cobalt existed as CoO; while it was single atom Co at 600 °C (Co-C-600); and small size CoO at 700 °C (Co-C-700). Co-C-X could activate PMS to produce hydroxyl radicals, sulfate radicals, high-valent cobalt-oxo and singlet oxygen, which depended on the pyrolysis temperature. Although Co-C-700 had the highest catalytic activity, the leaching cobalt was also highest (3.23 mg/L), compared with that of Co-C-500 (0.27 mg/L) and Co-C-600 (0.14 mg/L). Co-C-600 had fast degradation for atrazine, nitrobenzene , bisphenol A, phenol and 4-chlorophenol, which also had wide pH range and high tolerance to inorganic ions.
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VACUUM
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2022
·
IF 4.11
Peng Deng,Hua Fang,Rui Liu,Xueyong Guo,Pengwan Chen
The development of novel catalysts with high-activity to improve the thermal-induced pyrolysis of energetic molecular perovskite is of great importance. In this work, flower-like MnO 2 nanostructure was fabricated by a facile hydrothermal method with KMnO 4 as only precursor, and its thermal-induced pyrolysis performance of energetic molecular perovskite DAP-4 was studied. Results showed the catalysis thermal-induced pyrolysis peak temperature of DAP-4 had reduced by 50 °C from 386 °C (raw DAP-4) to 336 °C (DAP-4/10 wt% MnO 2 ) by the flower-like MnO 2 nanostructure , with rich oxygen vacancy added. The heat release of DAP-4 thermal-induced pyrolysis processes had a trend of increasing from 3423 J/g to 3563 J/g first and then decreasing to 2223 J/g. The apparent activation energy of DAP-4 had been reduced to 144 kJ/mol with addition of 10 wt% MnO 2 . The catalysis mechanism of MnO 2 with flower-like nanostructure on thermal-induced pyrolysis of DAP-4 was provided.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ze Zhang,Cunqian Fang,Yuanqi Weng,Xiao Luo,Qizhong Huang,Huiping Hu
Graphene was introduced into C/C–SiC composites via pressureless impregnation to enhance the mechanical and thermal properties of the composites. The effects of various graphene contents on the mechanical and ablative performances of C/C–SiC composites were investigated. The results showed that the ultimate bending stress and compressive stress of the C/C–SiC composites increased by 28.98% and 23.64%, respectively, after adding 7.25% graphene. Moreover, the ablation rates of the composites were vastly decreased after adding a slight graphene content (2.13%). However, the ablation rates increased with increasing of graphene content, indicating that the benefit of introducing graphene on the ablation property decreased, which was mainly ascribed to the relative reduction in the SiC content. As a result, introducing slight graphene into C/C–SiC composites had the greatest benefit on the anti-ablation performance.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Dezheng Sun,Fayong Li,Junwei Jin,Sangar Khan,Kamel Mohamed Eltohamy,Miaomiao He,Xinqiang Liang
Developing effective modification methods and obtaining a comprehensive understanding of adsorption mechanisms are essential for the practical application of biochars for the removal of heavy metals from solutions. In this study, rice straw was impregnated with sodium phytate and pyrolyzed at 350 °C, 450 °C, and 550 °C to synthesize modified biochars (i.e., MBC350, MBC450, and MBC550). The Cd(II) adsorption capacities and contributions of different mechanisms, including the effects of biochar-derived dissolved organic matter (BDOM), were investigated using batch sorption experiments and characterization analyses. The modification of sodium phytate promoted the pyrolysis of biomass, thereby increasing the BDOM content and aromatic structures at low and high pyrolysis temperatures, respectively. Moreover, the modification also increased the exchangeable Na + and carbonate contents in the modified biochars. Compared with the raw biochars, the Cd(II) adsorption capacities of modified biochars increased by 3.3–4.3 times, and MBC550 had the highest Cd(II) adsorption capacity (126.5 mg/g), of which precipitation with minerals and interaction with π-electrons contributed 41.7% and 45.8%, respectively. However, at a lower pyrolysis temperature, the Cd(II) adsorption attributed to ion exchange and co-deposition with BDOM significantly increased, especially on MBC350 (33.9 and 12.6 mg/g, respectively). These results indicate that modification by sodium phytate effectively enhanced various adsorption mechanisms, thereby increasing the Cd(II) adsorption capacity. In addition, the contribution of co-deposition with BDOM to adsorption was unneglectable for the biochars pyrolyzed at low temperatures.
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高影响因子
MATERIALS & DESIGN
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2022
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IF 9.417
Huadong Fu,Yan Qin,Zhenyue Zou,Jiamin Fan,Chenyi Xue
The interlaminar strength of polymer matrix laminates significantly affects their performance. Z-pinning is an effective method for improving the interlaminar performance of laminates. However, it remains a challenge to improve the interlaminar performance of polymer matrix laminates at high temperatures. In this study, the interlaminar performance of silica/phenolic laminate after high-temperature pyrolysis was enhanced by using a boron carbide/silicon carbide fibre (B 4 C/SiC f ) composite pin. Experimental results revealed that the in-plane interlaminar shear strength (ILSS) of the pyrolyzed B 4 C/SiC f z-pinned laminates was above 3.0 MPa, which was 110% higher than that of the unpinned laminate. In addition, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric analysis revealed that the combined effect of B 4 C and SiC fibres in the pin on the interlaminar performance of the laminate at high temperatures due to the enhancement in the interlaminar strength of the composite. Furthermore, the ILSS of the laminate increased when the z-pin content of the B 4 C/SiC f pins increased; however, when the content of the z-pin further increased, the vertical interlayer direction would happen the brittle fracture.
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ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Jie Li,Youcai Lu,Shiyu Ma,Zhongjun Li,Qingchao Liu
Li–O 2 battery has attracted wide attention because it can satisfy the need for a new energy storage system with high energy density. However, poor oxygen reduction (ORR)/oxygen evolution (OER) kinetics involving Li 2 O 2 formation/decomposition is a major obstacle to its development. By designing suitable cathode with desired structure and surface electronic states, the formation/morphology of Li 2 O 2 and the reaction kinetics of charge process can be efficiently optimized simultaneously. In this work, a novel sulfur (S) and chlorine (Cl) co-doped porous carbon (CSC) were synthesized by one-step pyrolysis strategy, and the amount of heterogeneous atoms could be flexibly controlled by different calcination temperatures . Experimental combined with theoretical calculations show that the content of C Cl bond plays an important role in the adsorption of intermediate LiO 2 , thus regulating the morphology of Li 2 O 2 and ultimately affecting the release of battery energy. The C S bond mainly acts on the dynamics of the ORR and OER processes, which has an important influence on improving the round-trip efficiency of the battery. Benefiting from the synergistic effect of heteroatoms , the electrochemical performances of the Li–O 2 battery, including round-trip efficiency, discharge capacity and cycling stability are greatly improved.
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