Thermal control systems for low-temperature heat rejection on a lunar base

One of the important issues in the design of a lunar base is the thermal control system (TCS) used to reject low-temperature heat from the base. The TCS ensures that the base and the components inside are maintained within an acceptable temperature range. The temperature of the lunar surface peaks at 400 K during the 336-hour lunar day. Under these circumstances, direct dissipation of waste heat from the lunar base using passive radiators would be impractical. Thermal control systems based on thermal storage, shaded radiators, and heat pumps have been proposed. Based on proven technology, innovation, realistic complexity, reliability, and near-term applicability, a heat pump-based TCS was selected as a candidate for early missions. In this report, Rankine-cycle heat pumps and absorption heat pumps (ammonia water and lithium bromide-water) have been analyzed and optimized for a lunar base cooling load of 100 kW

Electrochemical supercapacitors based on a novel graphene/conjugated polymer composite system

An efficient method for the preparation of a highly conducting hybrid material from graphene oxide nanosheets (GNS) and a novel conjugated polymer, poly(3,4-propylenedioxythiophene), is demonstrated. A functionalized monomer based on 3,4-propylenedioxythiophene, namely ProDOT-OH, was covalently functionalized with GNS, followed by oxidative polymerization to prepare GNS-f-PProDOT composites. The covalent functionalization process of GNS with the monomer ProDOT-OH was activated through the simple esterification reaction between the acyl chloride derivative on the nanosheets and the pendant hydroxyl group present in the monomer. Furthermore, the monomer functionalized GNS were co-polymerized with thiophene resulting in hybrid graphene nanostructures coated with highly conducting co-polymers with a room temperature electrical conductivity as high as 22.5 S cm(-1). The resulting hybrid materials were characterized using a range of analytical techniques. The specific capacitance value of the composite and the co-polymer hybrids at a scan rate of 10 mV s(-1) has been determined to be 158 and 201 F g(-1) respectively and hence particularly promising for supercapacitors.close232

Sodium ion storage in reduced graphene oxide

The performance of few-layered metal-reduced graphene oxide (RGO) as a negative electrode material in sodium-ion battery was investigated. Experimental and simulation results indicated that the as-prepared RGO with a large interlayer spacing and disordered structure enabled significant sodium-ion storage, leading to a high discharge capacity. The strong surface driven interactions between sodium ions and oxygen-containing groups and/or defect sites led to a high rate performance and cycling stability. The RGO anode delivered a discharge capacity of 272 mA h g(-1) at a current density of 50mAg(-1), a good cycling stability over 300 cycles and a superior rate capability. The present work provides new insights into optimizing RGOs for high-performance and low-cost sodium-ion batteries. (C) 2016 Elsevier Ltd. All rights reserved

Design and Advanced Manufacturing of NU-1000 Metal–Organic Frameworks with Future Perspectives for Environmental and Renewable Energy Applications

Metal–organic frameworks (MOFs) represent a relatively new family of materials that attract lots of attention thanks to their unique features such as hierarchical porosity, active metal centers, versatility of linkers/metal nodes, and large surface area. Among the extended list of MOFs, Zr-based-MOFs demonstrate comparably superior chemical and thermal stabilities, making them ideal candidates for energy and environmental applications. As a Zr-MOF, NU-1000 is first synthesized at Northwestern University. A comprehensive review of various approaches to the synthesis of NU-1000 MOFs for obtaining unique surface properties (e.g., diverse surface morphologies, large surface area, and particular pore size distribution) and their applications in the catalysis (electro-, and photo-catalysis), CO2 reduction, batteries, hydrogen storage, gas storage/separation, and other environmental fields are presented. The review further outlines the current challenges in the development of NU-1000 MOFs and their derivatives in practical applications, revealing areas for future investigation

r-2,c-6-Bis(3-methoxy­phen­yl)-t-3,t-5-dimethyl­piperidin-4-one

In the title compound, C21H25NO3, the piperidinone ring adopts a chair conformation with an equatorial orientation of all substituents; the 3-methoxy­phenyl groups make a dihedral angle of 60.26 (15)°. The carbonyl group O atom is disordered over two positions in a 0.643 (3):0.357 (3) ratio. The crystal structure is stabilized by N—H⋯O and C—H⋯O hydrogen bonding

Biomass derived carbon nanoparticle as anodes for high performance sodium and lithium ion batteries

In this paper, we report a flame deposition method to prepare carbon nanoparticles (CNPs) from coconut oil. The CNPs were further modified with a piranha solution to obtain surface-carboxylated carbon nanoparticles (c-CNPs). When used as an anode for sodium-ion batteries, the CNPs and c-CNPs respectively delivered discharge capacities of 277 and 278 mA h g in the second cycle at a current density of 100 mA g. At the 20th cycle, the capacities of CNP and c-CNPs were 217 and 206 mA h g respectively. The results suggest that modification of the CNPs with the piranha solution improved neither the charge storage capacity nor the stability against cycling in a sodium-ion battery. When the CNP and c-CNP were used an anode in a lithium-ion battery, 2nd-cycle discharge capacities of 741 and 742 mA h g respectively at a current density of 100 mA g were obtained. After 20 cycles the capacities of CNP and c-CNP became 464 and 577 mA h g respectively, showing the cycling stability of the CNPs was improved after modification. The excellent cycling performance, high capacity and good rate capability make the present material as highly promising anodes for both sodium-ion and lithium-ion batteries

Lithium-storage properties of gallic acid-reduced graphene oxide and silicon-graphene composites

Graphene oxide (GO) was de-oxygenated using gallic acid under mild conditions to prepare reduced graphene oxide (RGO). The resultant RGO showed a lithium-ion storage capacity of 1280\ua0mA\ua0h\ua0g at a current density of 200\ua0mA\ua0g after 350 cycles when used as an anode for lithium ion batteries. The RGO was further used to stabilize silicon (Si) nanoparticles to prepare silicon-graphene composite electrode materials. Experimental results showed that a composite electrode prepared with a mass ratio of Si:GO\ua0=\ua01:2 exhibited the best lithium ion storage performance

Graphene-based metal-organic framework hybrids for applications in catalysis, environmental, and energy technologies

Current energy and environmental challenges demand the development and design of multifunctional porous materials with tunable properties for catalysis, water purification, and energy conversion and storage. Because of their amenability to de novo reticular chemistry, metal-organic frameworks (MOFs) have become key materials in this area. However, their usefulness is often limited by low chemical stability, conductivity and inappropriate pore sizes. Conductive two-dimensional (2D) materials with robust structural skeletons and/or functionalized surfaces can form stabilizing interactions with MOF components, enabling the fabrication of MOF nanocomposites with tunable pore characteristics. Graphene and its functional derivatives are the largest class of 2D materials and possess remarkable compositional versatility, structural diversity, and controllable surface chemistry. Here, we critically review current knowledge concerning the growth, structure, and properties of graphene derivatives, MOFs, and their graphene@MOF composites as well as the associated structure- property-performance relationships. Synthetic strategies for preparing graphene@MOF composites and tuning their properties are also comprehensively reviewed together with their applications in gas storage/separation, water purification, catalysis (organo-, electro-, and photocatalysis), and electrochemical energy storage and conversion. Current challenges in the development of graphene@MOF hybrids and their practical applications are addressed, revealing areas for future investigation. We hope that this review will inspire further exploration of new graphene@MOF hybrids for energy, electronic, biomedical, and photocatalysis applications as well as studies on previously unreported properties of known hybrids to reveal potential "diamonds in the rough".Web of Science12224173381724

Graphene and molybdenum disulfide hybrids: Synthesis and applications

Graphene and related inorganic two-dimensional (2D) nanomaterials are an exceptional class of compounds with exotic properties that are technologically intriguing. While graphene itself is chemically inert and a gapless semimetal, its isostructural analog, molybdenum disulfide (MOS2) is chemically versatile with band gaps, thereby finding significant use in a myriad of applications. Although these 2D nanomaterials individually possess tremendous authority for various applications, the combination of these materials in the recent past has created a new paradigm in emerging applications. Here, we summarize the current state-of-the-art and progress over the past three years on the development of hybrids of these layered materials. We highlight their pivotal role in electrochemical energy storage, sensing, hydrogen generation by photochemical water splitting and electronic device applications such as field-effect transistors. Perspectives on the challenges and opportunities for the exploration of these 2D layered hybrid materials are put forwardopen1