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Optimal synthesis of heat-integrated distillation configurations using the two-column superstructure
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作者 Xiaodong Zhang Lu Jin Jinsheng Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第2期238-249,共12页
In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocol... In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocolumn configuration.However,this approach frequently necessitates tedious enumeration procedures,resulting in a considerable computational burden.To surmount this formidable challenge,the present study introduces an innovative remedy:The proposition of a superstructure that encompasses both single-column and multiple two-column configurations.Additionally,a simultaneous optimization algorithm is applied to optimize both the process parameters and heat integration structures of the twocolumn configurations.The effectiveness of this approach is demonstrated through a case study focusing on industrial organosilicon separation.The results underscore that the superstructure methodology not only substantially mitigates computational time compared to exhaustive enumeration but also furnishes solutions that exhibit comparable performance. 展开更多
关键词 SUPERSTRUCTURE process synthesis Heat integration Simulation-based optimization Industrial organosilicon separation
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A new,sustainable process for synthesis of ethylene glycol
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作者 Jinlong Gong 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2018年第4期949-950,共2页
In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups (e.g. OH) in the same mole... In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups (e.g. OH) in the same molecule, remaining intact [1]. Although the transformation of C1 species (e.g. CO, CO2, CH4 and CH3OH) into C2 molecules (e.g. C2H4, C2HsOH and HOCH2CH2OH) via C-C coupling has been a hot research topic but the yield of aimed product is still needed to be improved. Ethylene glycol (EG) is a versatile chemical with many important applications, in particular for the manufacture of polyesters, predominantly poly(ethylene terephthalate) [2]. Recently, Wang, Deng and co-workers at Xiamen University cleverly designed a new process for the conversion of methanol to ethylene glycol, in which the EG selectivity can reach 90% (Eq. (1)) [3]. 展开更多
关键词 EG OH A new sustainable process for synthesis of ethylene glycol
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Process synthesis for the separation of coal-to-ethanol products
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作者 Qingping Qu Daoyan Liu +1 位作者 Hao Lyu Jinsheng Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS 2024年第5期263-278,共16页
The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synth... The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synthesis of the ethanol distillation system is impracticable for exhaustive comparison and difficult for conventional superstructure-based optimization as rigorous models are used.This work adopts a superstructure-based framework,which combines the strategy that adaptively selects branches of the state-equipment network and the parallel stochastic algorithm for process synthesis.High-performance computing significantly reduces time consumption,and the adaptive strategy substantially lowers the complexity of the superstructure model.Moreover,parallel computing,elite search,population redistribution,and retention strategies for irrelevant parameters are used to improve the optimization efficiency further.The optimization terminates after 3000 generations,providing a flowsheet solution that applies two non-sharp splitting options in its distillation sequence.As a result,the 59-dimension superstructure-based optimization was solved efficiently via a differential evolution algorithm,and a high-quality solution with a 28.34%lower total annual cost than the benchmark was obtained.Meanwhile,the solution of the superstructure-based optimization is comparable to that obtained by optimizing a single specific configuration one by one.It indicates that the superstructure-based optimization that combines the adaptive strategy can be a promising approach to handling the process synthesis of large-scale and complex chemical processes. 展开更多
关键词 Coal-to-ethanol process synthesis Superstructure-based optimization Differential evolution algorithm Distillation
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ADVANCED SYNTHESIS OF LIGHT METALS
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作者 F.H. Froes(IMAP, University of Idaho, Moscow, ID 838443026, USA ) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1996年第6期531-536,共6页
The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidifica... The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidification, spray deposition, mechanical alloying, plasma Processing and vapor deposition. 展开更多
关键词 synthesis/processing powder metallurgy lightweight metals aluminum magnesium titanium rapid solidification spray depositin mechanical alloying Plasma processing vapor deposition
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苹果酸克立波必利的合成
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作者 黄雅钦 张丽娟 吴宪龙 《辽宁工学院学报》 1997年第4期55-56,共2页
苹果酸克立波必利是一种抗消化性溃疡新药,本文考查了其合成的工艺路线。
关键词 合成 多巴胺 消化系统药物 阻滞剂
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Automated synthesis of steady-state continuous processes using reinforcement learning 被引量:1
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作者 Quirin Göttl Dominik GGrimm Jakob Burger 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2022年第2期288-302,共15页
Automated flowsheet synthesis is an important field in computer-aided process engineering.The present work demonstrates how reinforcement learning can be used for automated flowsheet synthesis without any heuristics o... Automated flowsheet synthesis is an important field in computer-aided process engineering.The present work demonstrates how reinforcement learning can be used for automated flowsheet synthesis without any heuristics or prior knowledge of conceptual design.The environment consists of a steady-state flowsheet simulator that contains all physical knowledge.An agent is trained to take discrete actions and sequentially build up flowsheets that solve a given process problem.A novel method named SynGameZero is developed to ensure good exploration schemes in the complex problem.Therein,flowsheet synthesis is modelled as a game of two competing players.The agent plays this game against itself during training and consists of an artificial neural network and a tree search for forward planning.The method is applied successfully to a reaction-distillation process in a quaternary system. 展开更多
关键词 automated process synthesis flowsheet synthesis artificial intelligence machine learning reinforcement learning
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Research on the Fe-silicon nitride material self-producing N_2 at high temperature 被引量:1
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作者 Junhong Chen Xueda Wang +2 位作者 Jialin Sun Huasheng Zhan Wen Song 《Journal of University of Science and Technology Beijing》 CSCD 2006年第1期78-81,共4页
The Fe silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the ch... The Fe silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the change of the microstructure during calcination. The results showed that at 1127.2℃ the Fe-silicon nitride self-reacts and releases N2 and under 101.3 kPa the volume of N2 given out in the course of the reaction is 20 times more than that of the starting material. N2 is produced quickly, and completes in several decade seconds. With the producing of N2, the structure of Silicon Nitride around Fe becomes loose and porous, or cracks are formed by the reaction between Fe and silicon nitride. So if it is made use of that Fe-silicon nitride self-producing N2 at the high temperature, the performance of the material on a base of Fe-silicon nitride could be greatly improved. 展开更多
关键词 synthesis by flashing combustion process Fe-Silicon Nitride Nitrogen
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Experimental Investigation on Finishing Technology by Magnetostrictive Ultrasonic Vibration of Magnetic Liquid
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作者 陈善飞 顾邦明 +1 位作者 王正才 王正良 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第3期166-170,共5页
Magnetic liquid can produce alternative internal pressure under the alternative high-frequency gradient magnetic field.Because it has higher bulk modulus,the internal pressure results in its volume change.Using piezoe... Magnetic liquid can produce alternative internal pressure under the alternative high-frequency gradient magnetic field.Because it has higher bulk modulus,the internal pressure results in its volume change.Using piezoelectric transducers,the ultrasonic wave generated by the vibration of magnetic liquids can be detected,which shows that the magnetic liquids have the magnetostrictive effect and can generate the ultrasonic vibration under the alternative magnetic gradient field.Some nonmagnetic abrasives and rust-proofing agents can be mixed into the magnetic liquids,under the alternative magnetic field,the abrasives held by magnetic liquids grind the surface of the workpieces,and thus,the finishing for the surface with complex shape,mold cavity and inner wall of tiny tubes can be realized. 展开更多
关键词 materials synthesis and processing technology FINISHING magnetic liquid MAGNETOSTRICTIVE ultrasonic vibration
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MILP synthesis of separation processes for waste oil-in-water emulsions treatment
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作者 Zorka N. Pintaric Gorazd P. Skof Zdravko Kravanja 《Frontiers of Chemical Science and Engineering》 SCIE EI CAS CSCD 2016年第1期120-130,共11页
This paper presents a novel synthesis method for designing integrated processes for oil-in-water (O/W) emulsions treatment. General superstructure involving alternative separation technologies is developed and model... This paper presents a novel synthesis method for designing integrated processes for oil-in-water (O/W) emulsions treatment. General superstructure involving alternative separation technologies is developed and modelled as a mixed integer linear programming (MILP) model for maximum annual profit. Separation processes in the superstructure are divided into three main sections of which the pretreatment and final treatment are limited to the selection of one altemative (or bypass) only, while within the intermediate section various combinations of different technologies in series can be selected. Integrated processes composed of selected separation techniques for given ranges of input chemical oxygen demand (COD) can be proposed by applying parametric analyses within the superstructure approach. This approach has been applied to an existing industrial case study for deriving optimal combinations of technologies for treating diverse oil-in- water emulsions within the range of input COD values between 1000 mg-L-1 and 145000 mgL t. The optimal solution represents a flexible and profitable process for reducing the COD values below maximal allowable limits for discharging effluent into surface water. 展开更多
关键词 oil-in-water emulsion chemical oxygen demand SUPERSTRUCTURE process synthesis MILP
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硬脂酰乳酸钠的工业化合成新工艺
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作者 徐怀义 杨佳 闵菊平 《中国食品添加剂》 北大核心 2017年第10期130-134,共5页
硬脂酰乳酸钠(SSL)属于阴离子型乳化剂,能与淀粉和蛋白质结合形成络合物,改善食物内部的组织结构,使其品质得以提高。以乳酸和硬脂酸为原料,新型的磷酸复配物作为催化剂,通过单因素实验和正交实验,得到一步合成硬脂酰乳酸钠(SSL)的新工... 硬脂酰乳酸钠(SSL)属于阴离子型乳化剂,能与淀粉和蛋白质结合形成络合物,改善食物内部的组织结构,使其品质得以提高。以乳酸和硬脂酸为原料,新型的磷酸复配物作为催化剂,通过单因素实验和正交实验,得到一步合成硬脂酰乳酸钠(SSL)的新工艺:在真空负压条件下,先聚合、酯化后中和,乳酸与硬脂酸摩尔比为1.9∶1,催化剂用量为硬脂酸质量的2.0%,反应温度为160℃,反应时间为4h,中和剂用量为硬脂酸质量的24%。由于采用温和的磷酸复配物作为催化剂以及采用真空负压、低温的反应条件,该工艺特别适合于工业化大生产。 展开更多
关键词 硬脂酰乳酸钠 磷酸复配物 合成 新工艺
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Recycling the spent electronic materials to construct a highperformance Cu_(1.94)S/ZnS heterostructure anode of sodium-ion batteries
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作者 Xiaowei He Tianshuai Wang +1 位作者 Lidong Tian Qiuyu Zhang 《Nano Research》 SCIE EI CSCD 2024年第5期4006-4015,共10页
Heterostructure engineering by coupling different nanocrystals has received extensive attention because it can enhance the reaction kinetics of the anode of sodium-ion batteries(SIBs).However,constructing high-quality... Heterostructure engineering by coupling different nanocrystals has received extensive attention because it can enhance the reaction kinetics of the anode of sodium-ion batteries(SIBs).However,constructing high-quality heterostructure anode materials through green and environmentally friendly methods remains a challenge.Herein,we have proposed a simple one-step method by recycling the electronic waste metal materials to synthesize the Cu_(1.94)S/ZnS heterostructure materials.Combined with the experimental analysis and first principle calculations,we find that the synergistic effect of different components in heterostructure structures can significantly enhance the reversible capacity and rate performance of anode materials.Based on the constructed Cu_(1.94)S/ZnS anode,we obtain a superior reversible capacity of 440 mAh·g^(-1) at 100 mA·g^(-1) and 335 mAh·g^(-1) after 3000 cycles at 2000 mA·g^(-1).Our work sheds new light on designing high-rate and capacity anodes for SIBs through the greenness synthesis method. 展开更多
关键词 sodium-ion batteries HETEROSTRUCTURE reversible capacity environmentally synthesis process
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One-pot synthesis of nuclear targeting carbon dots with high photoluminescence
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作者 Pengchong Wang Hongrui Ji +5 位作者 Shiyan Guo Ying Zhang Yan Yan Ke Wang Jianfeng Xing Yalin Dong 《Chinese Chemical Letters》 SCIE CAS CSCD 2021年第12期3911-3915,共5页
Carbon dots(CDs) are novel fluorescent nanomaterials with good water solubility, high resistance to photobleaching and low toxicity. While, there are few studies elaborate on the relationship among reaction conditions... Carbon dots(CDs) are novel fluorescent nanomaterials with good water solubility, high resistance to photobleaching and low toxicity. While, there are few studies elaborate on the relationship among reaction conditions, properties and applications of CDs. In this study, a series of CDs are synthesized through a one-pot hydrothermal method, and different reaction conditions are carried out to study the influencing factors of CDs properties. As a result, with the increase of temperature and reaction time, the particle size and zeta potential of CDs increased, the maximum emission wavelength red-shifted and the fluorescence quantum yield(QY) improved. Among them, CD3006 has good water solubility and highest QY of 81.4%, which is beneficial for its applications in bioimaging and ion detection. CD3006 is almost nontoxic in cells at a concentration of 500 μg/m L. In addition, the positive charged CD3006 shows nuclear targeting potential because of its combination with DNA through electrostatic interaction in nucleus. The properties of CDs can be greatly enhanced by controlling reaction conditions, and it provides great application prospects. 展开更多
关键词 Optimization of synthesis process Fluorescence quantum yield improving Nuclear targeting BIOIMAGING Ferric ion detection
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Advances in scalable gas-phase manufacturing and processing of nanostructured solids: A review 被引量:3
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作者 Samir Salameh Jesus Gomez-Hernandez +2 位作者 Aristeidis Goulas Hao Van Bui J. Ruud van Ommen 《Particuology》 SCIE EI CAS CSCD 2017年第1期15-39,共25页
Although the gas-phase production of nanostructured solids has already been carried out in industry for decades, only in recentyears has research interest in this topic begun to increase. Nevertheless, despite the rem... Although the gas-phase production of nanostructured solids has already been carried out in industry for decades, only in recentyears has research interest in this topic begun to increase. Nevertheless, despite the remarkable scientific progress made recently, many long-established processes are still used in industry. Scientific advancements can potentially lead to the improvement of existing industrial processes, but also to the development of completely new routes. This paper aims to review state-of-the-art synthesis and processing technologies, as well as the recent developments in academic research. Flame reactors that produce inorganic nanoparticles on industrial- and lab-scales are described, alongside a detailed overview of the different systems used for the production of carbon nanotubes and graphene. We discuss the problems of agglomeration and mixing of nanoparticles, which are strongly related to synthesis and processing. Finally, we focus on two promising processing techniques, namely nanoparticle fluidization and atomic layer deposition. 展开更多
关键词 Nanoparticle synthesis Gas-phase process Nanoparticle fluidization Atomic layer deposition Agglomeration
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Photocatalytic degradation of aqueous Methyl Orange using nitrogen-doped TiO_2 photocatalyst prepared by novel method of ultraviolet-assisted thermal synthesis 被引量:5
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作者 Mohsen Nasirian Mehrab Mehrvar 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第4期81-93,共13页
A nitrogen-doped titanium dioxide composite photocatalyst(N–TiO2) with heterojunction structures is synthesized by three different approaches: a novel UV-assisted thermal synthesis, annealing, and microwave techni... A nitrogen-doped titanium dioxide composite photocatalyst(N–TiO2) with heterojunction structures is synthesized by three different approaches: a novel UV-assisted thermal synthesis, annealing, and microwave technique. Photocatalytic activities of synthesized photocatalysts are evaluated by the degradation of Methyl Orange under ultraviolet light types A(UV-A), B(UV-B), and C(UV-C), visible light, and direct sunlight irradiation. Results show that by using N–TiO_2 photocatalyst prepared by the UV-assisted thermal synthesis and annealing, the degradation increases by 16.5% and 20.4%, respectively, compared to that by bare TiO2. The best results are obtained at a nitrogen to TiO2 mass ratio of 0.15(N:TiO2). The enhancement of the photocatalytic activity observed in the visible range is mainly attributed to the increasing separation rate of photogenerated charge carriers. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method for the nitrogen-doped TiO2 photocatalyst; thus, further studies are recommended for process optimization, immobilization, and scale-up to evaluate its applicability in wastewater treatment. 展开更多
关键词 Ultraviolet-assisted thermal synthesis N–TiO2 Photocatalysis Advanced oxidation processes
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Revealing milling durations and sintering temperatures on conductivity and battery performances of Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte 被引量:1
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作者 Shuai Chen Chuang Yu +3 位作者 Chaochao Wei Linfeng Peng Shijie Cheng Jia Xie 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第5期525-529,共5页
Halide electrolytes in solid-state batteries with excellent oxidative stability and high ionic conductivity have been well reported recently.However,the high-cost rare-earth elements and long duration of highrotation ... Halide electrolytes in solid-state batteries with excellent oxidative stability and high ionic conductivity have been well reported recently.However,the high-cost rare-earth elements and long duration of highrotation milling procure are the major obstacles.Herein,we have successfully synthesized the low cost Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte consisting of abundant elements with comparable Li-ion conductivity in a short milling duration of 4 h.Phase transition of the annealed sample was also carefully investigated.Li Ni_(0.6)Co_(0.2)Mn_(0.2)O_(2)/Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)/Li_(5.5)PS_(4.5)Cl_(1.5)/In-Li batteries using different halide electrolytes were constructed and cycled at different voltage windows.Solid-state battery using Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte obtained from long milling duration delivers higher discharge capacities and superior capacity retention than shorter milling time between 3.0 and 4.3 V.It delivers much higher discharge capacity when cycled at elevated temperature(60℃)and suffers fast capacity degradation when the upper cut-off voltage increases to 4.5 V at the same current density.This work provides an efficiency synthesis strategy for halide solid electrolyte and studies its applications in all-solid-state batteries in a wide temperature range. 展开更多
关键词 Solid inorganic electrolyte Solid state battery Halide electrolyte High temperature synthesis process
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Synthesis of ZrC Nanoparticles in the ZrO_2–Mg–C–Fe System Through Mechanically Activated Self-Propagating High-Temperature Synthesis
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作者 Abdollah Hajalilou Mansor Hashim +3 位作者 Halimah Mohamed kamari Kazem Javadi Samikannu Kanagesan Mohammad Parastegari 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第6期1144-1151,共8页
ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion tem... ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion(SHS) mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of(5–40) wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature(Tad) decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids. 展开更多
关键词 Mechanical activation(MA) Combustion synthesis Fe–ZrC composite Leaching process
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MgO-based adsorbents for CO2 adsorption:Influence of structural and textural properties on the CO_2 adsorption performance 被引量:3
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作者 Gutiérrez-Bonilla Elvira Granados-Correa Francisco +1 位作者 Sánchez-Mendieta Víctor Morales-Luckie Raúl Alberto 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第7期418-428,共11页
A series of MgO-based adsorbents were prepared through solution–combustion synthesis and ball-milling process.The prepared MgO-based powders were characterized using X-ray diffraction,scanning electron microscopy,N_2... A series of MgO-based adsorbents were prepared through solution–combustion synthesis and ball-milling process.The prepared MgO-based powders were characterized using X-ray diffraction,scanning electron microscopy,N_2 physisorption measurements,and employed as potential adsorbents for CO_2 adsorption.The influence of structural and textural properties of these adsorbents over the CO_2 adsorption behaviour was also investigated.The results showed that MgO-based products prepared by solution–combustion and ball-milling processes,were highly porous,fluffy,nanocrystalline structures in nature,which are unique physico-chemical properties that significantly contribute to enhance their CO_2 adsorption.It was found that the MgO synthesized by solution combustion process,using a molar ratio of urea to magnesium nitrate(2:1),and treated by ball-milling during 2.5 hr(MgO-BM2.5h),exhibited the maximum CO_2 adsorption capacity of 1.611 mmol/g at 25℃ and 1 atm,mainly via chemisorption.The CO_2 adsorption behaviour on the MgO-based adsorbents was correlated to their improved specific surface area,total pore volume,pore size distribution and crystallinity.The reusability of synthesized MgO-BM2.5h was confirmed by five consecutive CO_2adsorption–desorption times,without any significant loss of performance,that supports the potential of MgO-based adsorbent.The results confirmed that the special features of MgO prepared by solution–combustion and treated by ball-milling during 2.5 hr are favorable to be used as effective MgO-based adsorbent in post-combustion CO_2 capture technologies. 展开更多
关键词 CO_2 adsorption MgO-based adsorbents Porous materials Solution–combustion synthesis Ball-milling process Textural properties
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Sodium-doped carbon nitride nanotubes for efficient visible light-driven hydrogen production 被引量:1
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作者 Longshuai Zhang Ning Ding +10 位作者 Muneaki Hashimoto Koudai Iwasaki Noriyasu Chikamori Kazuya Nakata Yuzhuan Xu Jiangjian Shi Huijue Wu Yanhong Luo Dongmei Li Akira Fujishima Qingbo Meng 《Nano Research》 SCIE EI CAS CSCD 2018年第4期2295-2309,共15页
Sodium-doped carbon nitride nanotubes (Nax-CNNTs) were prepared by a green and simple two-step method and applied in photocatalytic water splitting for the first time. Transmission electron microscopy (TEM) elemen... Sodium-doped carbon nitride nanotubes (Nax-CNNTs) were prepared by a green and simple two-step method and applied in photocatalytic water splitting for the first time. Transmission electron microscopy (TEM) element mapping and X-ray photoelectron spectroscopy (XPS) measurements confirm that sodium was successfully introduced in the carbon nitride nanotubes (CNNTs), and the intrinsic structure of graphitic carbon nitride (g-C3N4) was also maintained in the products. Moreover, the porous structure of the CNNTs leads to relatively large specific surface areas. Photocatalytic tests indicate that the porous tubular structure and Na+ doping can synergistically enhance the hydrogen evolution rate under visible light (λ 〉 420 nm) irradiation in the presence of sacrificial agents, leading to a hydrogen evolution rate as high as 143 μmol·h-1 (20 mg catalyst). Moreover, other alkali metal-doped CNNTs, such as Lix-CNNTs and Kx-CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Nax-CNNTs. This highlights the general applicability of the present method to prepare alkali metal-doped CNNTs; a preliminary mechanism for the photocatalytic hydrogen evolution reaction in the Nax-CNNTs is also proposed. 展开更多
关键词 graphitic carbon nitrides nanotubes alkali metal doping photocatalytic hydrogen production hydrothermal/thermopolymerization processes two-step synthesis
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