http://pubs.acs.org/doi/pdfplus/10.1021/cr300162p

Deep Eutectic Solvents (DESs) and Their Applications

Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.

Deep eutectic solvents: syntheses, properties and applications

Porous carbons have several advantageous properties with respect to their use in energy applications that require constrained space such as in electrode materials for supercapacitors and as solid state hydrogen stores. The attractive properties of porous carbons include, ready abundance, chemical and thermal stability, ease of processability and low framework density. Activated carbons, which are perhaps the most explored class of porous carbons, have been traditionally employed as catalyst supports or adsorbents, but lately they are increasingly being used or find potential applications in the fabrication of supercapacitors and as hydrogen storage materials. This manuscript presents the state-of-the-art with respect to the preparation of activated carbons, with emphasis on the more interesting recent developments that allow better control or maximization of porosity, the use of cheap and readily available precursors and tailoring of morphology. This review will show that the renewed interest in the synthesis of activated carbons is matched by intensive investigations into their use in supercapacitors, where they remain the electrode materials of choice. We will also show that activated carbons have been extensively studied as hydrogen storage materials and remain a strong candidate in the search for porous materials that may enable the so-called Hydrogen Economy, wherein hydrogen is used as an energy carrier. The use of activated carbons as energy materials has in the recent past and is currently experiencing rapid growth, and this review aims to present the more significant advances.

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Energy storage applications of activated carbons: supercapacitors and hydrogen storage

Hydrogen storage for transportation applications requires high volumetric and gravimetric storage capacity. B-N compounds are well suited as storage materials due to their light weight and propensity for bearing multiple protic (N-H) and hydridic (B-H) hydrogens. This critical review briefly covers the various methods of hydrogen storage, and then concentrates on chemical hydrogen storage using B-N compounds. The simplest B-N compound, ammonia borane (H3NBH3), which has a potential 19.6 wt% hydrogen storage capacity, will be emphasised (127 references).

B–N compounds for chemical hydrogen storage

The disclosure provides for multivariant zeolitic imidazolate frameworks (ZIFs), methods of making thereof, and methods of use therefrom.

/pdf/zeolitic-imidazolate-frameworks-3a597d03ld.pdf

Zeolitic imidazolate frameworks

Hydrogen storage in several microporous zeolites

We prepared several different surfaces and pore volumes on small pore zeolites by hydrothermal synthesis and ion exchange (Li+, Na+, and Ca2+) based on three basic gas diameter grade structures of zeolites: KFI (0.39 × 0.39 nm), CHA (0.38 × 0.38 nm), and LEV (0.36 × 0.48 nm), which were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis. The surface area and microporous volumes were calculated using the Dubinin–Radushkevitch (D-R) equation based on CO2 adsorption at 273 K. The CHA was synthesized with a lower Si/Al ratio, and the surfaces and microporous volumes were changed greatly by ion exchange. KFI had a higher Si/Al ratio, and the scope of the surface could be kept smaller. Focusing on the CO2, CH4, and N2 adsorption isotherms at high pressure (1 MPa), we found that the samples were exchanged by Li+ and Na+ with bigger surfaces and greater adsorption volumes. The orifice diameter was very important in the sieving of CO2 and N2 or CO2 and CH4, while N...

Adsorption of CO2, CH4, and N2 on Gas Diameter Grade Ion-Exchange Small Pore Zeolites

Ionothermal synthesis of a three-dimensional zinc phosphate with DFT topology using unstable deep-eutectic solvent as template-delivery agent

Bismuth plays important roles in promoting the oxidation of alcohols towards high-value-added chemicals over a noble metal loading catalyst. Herein, Mg–Al hydrotalcite-supported platinum–bismuth nanoparticles (Pt–Bi/HT) were prepared by the co-impregnation method and used in the selective oxidation of glycerol towards dihydroxyacetone (DHA). The incorporation of Bi species into Pt/HT significantly enhances the conversion of glycerol and the selectivity of DHA. The high selectivity of DHA with 80.6% could be achieved at 25.1% conversion of glycerol. The Bi species of the Pt–Bi/HT catalyst mainly exist in the form of BiOCl and Bi metal, which is different from the previous Pt–Bi based catalyst, confirmed by a combination of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). A plausible mechanism is proposed to elucidate the promoting role of Bi species on the Pt/HT catalyst in the selective oxidation of glycerol towards DHA.

Promoting Role of Bismuth on Hydrotalcite-Supported Platinum Catalysts in Aqueous Phase Oxidation of Glycerol to Dihydroxyacetone

The tribological properties of α-Zr(HPO4)·H2O and Cu(OH)2Zr(HPO4)2·2H2O (α-ZrP and Cu-α-ZrP, respectively) were investigated in lithium grease by using an optimol SRV-V oscillating reciprocating friction and wear tester (SRV). α-ZrP had excellent anti-wear and friction-reducing properties regardless of the applied load, frequency, and test duration. The applied load for α-ZrP reached 600 N, and the corresponding friction coefficient was 0.082. At 60 Hz, the wear volume rate was 11.16 × 10−9 mm3/Nm. The tribological properties of Cu-α-ZrP were dependent on the test conditions, especially at higher frequency. The α-ZrP worn steel surfaces were smooth and shallow as indicated from scanning electron microscopy and a three-dimensional non-contact surface mapping profiler. Related elements were detected by energy-dispersive X-ray spectroscopy on the rubbed surfaces. A boundary solid film may form on the worn surfaces after friction tests. In reciprocating mode, α-ZrP stuck on the contacting surfaces, which enabled it to form a stable solid lubricant film more effectively than Cu-α-ZrP. The crystal structure may be important for film strength under high loads, especially at high speed.

Hong Xu

Papers

Hydrogen storage in several microporous zeolites

Adsorption of CO2, CH4, and N2 on Gas Diameter Grade Ion-Exchange Small Pore Zeolites

Ionothermal synthesis of a three-dimensional zinc phosphate with DFT topology using unstable deep-eutectic solvent as template-delivery agent

Promoting Role of Bismuth on Hydrotalcite-Supported Platinum Catalysts in Aqueous Phase Oxidation of Glycerol to Dihydroxyacetone

Tribological Investigation of Two Different Layered Zirconium Phosphates as Grease Additives Under Reciprocating Sliding Test