Fabrication of nitrogen doped ordered mesoporous carbon derived from glucosamine with hybrid capacitive behaviors

Deyi Zhang,Mei Han,Yubing Li,Bing Wang,Yi Wang,Kunjie Wang,Huixia Feng 한국탄소학회 2017 Carbon Letters Vol.23 No.-

This paper introduces a nitrogen-doped ordered mesoporous carbon (NOMC) derived from glucosamine with hybrid capacitive behaviors, achieved by successfully combining electrical double-layer capacitance with pseudo-capacitance behaviors. The nitrogen doping content of the fabricated NOMC reached 7.4 at% while its specific surface area (SBET) and total pore volume reached 778 m2 g?1 and 1.17 cm3 g?1, respectively. A dual mesoporous structure with small mesopores centered at 3.6 nm and large mesopores centered at 9.9 nm was observed. The specific capacitance of the reported materials reached up to 328 F g?1, which was 2.1 times higher than that of pristine CMK-3. The capacitance retention rate was found to be higher than 87.9% after 1000 charge/discharge cycles. The supplementary pseudocapacitance as well as the enhanced wettability and conductivity due to the incorporation of nitrogen heteroatoms within the carbon matrixes were found to be responsible for the excellent capacitive performance of the reported NOMC materials.

Removal of methylene blue from aqueous solution by a carbon-microsilica composite adsorbent

Deyi Zhang,Ying Ma,Huixia Feng,Heming Luo,Jiao Chen,Yuan Hao 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.6

Microsilica, one kind of industrial solid waste material, was utilized firstly to prepare a carbon-microsilica composite adsorbent (CMS). The prepared adsorbent was characterized with XPS, SEM and Gas sorption experiments. The results indicated the SO3H groups, which are very effective in capturing cationic organic dye, were introduced onto the surface of CMS; the Brunauer-Emmett-Teller (BET) surface area (SBET) and total pore volume (Vtotal) of CMS reach 51m2/g and 0.045 cm3/g, respectively. Meanwhile, the possibility of the utilization of the adsorbent for removal of methylene blue (MB) from aqueous solution was investigated. The effect of pH, contact time and initial MB concentration for MB removal were studied. Equilibrium data were modeled using the Langmuir, Freundlich and Dubinin-Radushkevich equations to describe the equilibrium isotherms. It was found that data fit to the Langmuir equation better than the Freundlich equation. Maximum monolayer adsorption capacity was calculated at different temperatures (298,308, and 318 K) reach 251.81, 283.76 and 309.70 mg/g, respectively. It was observed that adsorption kinetics obeys the pseudo- first-order equation.

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self-activation of biomass: excellent rate capability and cycle stability

Zhang Zhijian,He Jingjing,Tang Xingchang,Wang Yuling,Yang Binbin,Wang Kunjie,Zhang Deyi 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self‑activation of biomass: excellent rate capability and cycle stability

Zhijian Zhang,Jingjing He,Xingchang Tang,Yuling Wang,Binbin Yang,Kunjie Wang,Deyi Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

Stochastic Programming for the Optimization of Transportation-Inventory Strategy

Deyi, Mou,Xiaoqian, Zhang Korean Institute of Industrial Engineers 2017 Industrial Engineeering & Management Systems Vol.16 No.1

In today's competitive environment, supply chain management is a major concern for a company. Two of the key issues in supply chain management are transportation and inventory management. To achieve significant savings, companies should integrate these two issues instead of treating them separately. In this paper we develop a framework for modeling stochastic programming in a supply chain that is subject to demand uncertainty. With reasonable assumptions, two stochastic programming models are presented, respectively, including a single-period and a multi-period situations. Our assumptions allow us to capture the stochastic nature of the problem and translate it into a deterministic model. And then, based on the genetic algorithm and stochastic simulation, a solution method is developed to solve the model. Finally, the computational results are provided to demonstrate the effectiveness of our model and algorithm.

Organo-layered double hydroxides for the removal of polycyclic aromatic hydrocarbons from soil washing effluents containing high concentrations of surfactants

Zhang, Ming,Zhao, Cheng,Li, Jinye,Xu, Liheng,Wei, Fang,Hou, Deyi,Sarkar, Binoy,Ok, Yong Sik Elsevier 2019 Journal of hazardous materials Vol.373 No.-

<P><B>Abstract</B></P> <P>Disposal of soil washing effluent (SWE) resulting from the surfactant-enhanced remediation of soil containing hydrophobic organic contaminants (HOCs)is complicated because of the presence of high levels of surfactants. The synthesized layered double hydroxides (LDHs), modified with sodium dodecyl sulfonate (SDS) in different loading amounts (organo-LDHs),were evaluated in this study as sorbents for the removal of two typical HOCs, phenanthrene (PHE) and pyrene (PYR),from a simulative SWE. The results showed that the organo-LDHs can effectively sorb PHE and PYR from the SWE within an equilibrium time of 2 h. All isotherms were linear and the sorption capabilities of the organo-LDHs increased almost linearly with the increase in the amount of SDS loaded on the LDHs. Besides, the surface areas of the organo-LDHs decreased sharply with the increase in SDS loading owing to the hindrance of the exposed surface of the LDHs by the incorporated SDS. These findings indicated that partitioning dominated the sorption process rather than adsorption, and the strong affinity of HOCs towards the organic phase in LDHs assisted in the effective removal of polycyclic aromatic hydrocarbons (PAHs) from the SWE. Furthermore, the sorption capabilities of organo-LDHs towards PHE and PYR at the higher loading amounts of SDS were much greater than that of commercial activated carbon at the higher concentration ranges of PAHs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dodecyl sulfonate anion modified LDHs are employed for the removal of PHE and PYR in soil washing effluent (SWE). </LI> <LI> Organo-LDHs showed superior performance in PHE removal from SWE than that of commercial activated carbon. </LI> <LI> Partitioning of PHE and PYR in the organic fraction of the organo-LDHs was the main mechanism. </LI> <LI> Using organo-LDHs for the separation of HOCs from surfactants in SWE facilitated reuse of the surfactants. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Molecular Beam Epitaxy of Highly Crystalline Monolayer Molybdenum Disulfide on Hexagonal Boron Nitride

Fu, Deyi,Zhao, Xiaoxu,Zhang, Yu-Yang,Li, Linjun,Xu, Hai,Jang, A-Rang,Yoon, Seong In,Song, Peng,Poh, Sock Mui,Ren, Tianhua,Ding, Zijing,Fu, Wei,Shin, Tae Joo,Shin, Hyeon Suk,Pantelides, Sokrates T.,Zho American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.27

<P>Atomically thin molybdenum disulfide (MoS2), a direct-band-gap semiconductor, is promising for applications in electronics and optoelectronics, but the scalable synthesis of highly crystalline film remains challenging. Here we report the successful epitaxial growth of a continuous, uniform, highly crystalline monolayer MoS2 film on hexagonal boron nitride (h-BN) by molecular beam epitaxy. Atomic force microscopy and electron microscopy studies reveal that MoS2 grown on h-BN primarily consists of two types of nucleation grains (0 aligned and 60 degrees antialigned domains). By adopting a high growth temperature and ultralow precursor flux, the formation of 60 degrees antialigned grains is largely suppressed. The resulting perfectly aligned grains merge seamlessly into a highly crystalline film. Large-scale monolayer MoS2 film can be grown on a 2 in. h-BN/sapphire wafer, for which surface morphology and Raman mapping confirm good spatial uniformity. Our study represents a significant step in the scalable synthesis of highly crystalline MoS2 films on atomically flat surfaces and paves the way to large-scale applications.</P>

Stochastic Programming for the Optimization of Transportation-Inventory Strategy

Mou Deyi,Zhang Xiaoqian 대한산업공학회 2017 Industrial Engineeering & Management Systems Vol.16 No.1

In today’s competitive environment, supply chain management is a major concern for a company. Two of the key issues in supply chain management are transportation and inventory management. To achieve significant savings, companies should integrate these two issues instead of treating them separately. In this paper we develop a framework for modeling stochastic programming in a supply chain that is subject to demand uncertainty. With reasonable assumptions, two stochastic programming models are presented, respectively, including a single-period and a multi-period situations. Our assumptions allow us to capture the stochastic nature of the problem and translate it into a deterministic model. And then, based on the genetic algorithm and stochastic simulation, a solution method is developed to solve the model. Finally, the computational results are provided to demonstrate the effectiveness of our model and algorithm.

Simple and green fabrication of a biomass-derived N and O self-doped hierarchical porous carbon via a self-activation route for supercapacitor application

Yang Binbin,Zhang Deyi,He Jingjing,Wang Yuling,Wang Kunjie,Li Hongxia,Wang Yi,Miao Lei,Ren Ruiye,Xie Mei 한국탄소학회 2020 Carbon Letters Vol.30 No.6

To meet the increased performance and cost requirements of commercial supercapacitor, a N and O self-doped hierarchical porous carbon is fabricated via a green and simple self-activation route utilizing leaves of wild hollyhock as raw materials. Comparing to commercial activated carbon, the reported material exhibits some marked merits, such as simple and green fabrication process, low cost, and superior capacitance performance. The specifc surface area of the obtained N and O co�doped hierarchical porous carbon arrives 954 m2 g−1, and the content of the self-doped nitrogen and oxygen reaches 2.64 at.% and 7.38 at.%, respectively. The specifc capacitance of the obtained material reaches 226 F g−1 while the specifc capacitance of the symmetric supercapacitor arrives 47.3 F g−1. Meanwhile, more than 90.3% of initial specifc capacitance is kept under a current density of 20 A g−1, and no arresting degradation is observed for capacitance after 5000 times cycle, perfectly demonstrating the excellent cycle and rate capability of the obtained material. The obtained N and O co-doped hierarchical porous carbon are expected to be an ideal substitution for commercial activated carbon.

Supercapacitive behavior of mesoporous carbon CMK-3 in calcium nitrate aqueous electrolyte

Heming Luo,Deyi Zhang,Liwen Zheng,Longyan Lei,Jingxiang Wu,Jian Yang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.4

Calcium nitrate Ca(NO3)2 aqueous solution was found to be an effective aqueous electrolyte for a supercapacitorusing ordered mesoporous carbon as the electrode materials. The supercapacitive behavior of ordered mesoporouscarbon CMK-3 electrode in Ca(NO3)2 aqueous electrolyte was investigated utilizing cyclic voltammetry (CV),electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge measurements. CMK-3 electrodeshows excellent supercapacitive behavior with wide voltage window, high specific gravimetric capacitance and satisfactoryelectrochemical stability in Ca(NO3)2 aqueous electrolyte. The specific gravimetric capacitance of CMK-3 electrodein Ca(NO3)2 aqueous electrolyte reaches 210 F g−1 at a current density of 1 A g−1, which is higher than that in conventionalaqueous electrolytes NaNO3 and KOH solution about 40% and 54%, respectively. The high charge density of the electricdouble layer formed at the interface of the CMK-3 electrode and Ca(NO3)2 aqueous electrolyte and the pseudo-capacitiveeffect originating from the oxygen groups on the surface of CMK-3 were believed to respond for the excellent supercapacitivebehavior of CMK-3 electrode in Ca(NO3)2 aqueous electrolyte.