Liquid Na/K Alloy Interfacial Synthesis of Functional Porous Carbon at Ambient Temperature.

The functional groups in porous carbon generally suffer a severe loss during the high-temperature carbonization. Instead, the low-temperature synthesis of carbon featuring porous structures and abundant functional groups is not only a solution that evades the pitfalls of pyrolysis but also is of significance for the development of synthetic methodology. Herein, a liquid metal interfacial engineering strategy is reported for the synthesis of porous carbon using CCl4 as the carbon precursor and sodium-potassium alloy (NaK) as the reducing agent, which is superior to traditional synthetic methods because it enables the engineering of a highly active liquid metal alloy microemulsion to directly generate porous carbon at ambient temperature. As synthesized porous carbon featured abundant carbon-chlorine bonds can be tandem-grafted with imidazole and 1,2-dibromoethane to achieve a CO2 cycloaddition catalyst, which exhibits excellent catalytic activity, in addition to exceptional stability.

Chemically bonded phosphorus/graphene hybrid as a high performance anode for sodium-ion batteries.

Room temperature sodium-ion batteries are of great interest for high-energy-density energy storage systems because of low-cost and natural abundance of sodium. Here, we report a novel phosphorus/graphene nanosheet hybrid as a high performance anode for sodium-ion batteries through facile ball milling of red phosphorus and graphene stacks. The graphene stacks are mechanically exfoliated to nanosheets that chemically bond with the surfaces of phosphorus particles. This chemical bonding can facilitate robust and intimate contact between phosphorus and graphene nanosheets, and the graphene at the particle surfaces can help maintain electrical contact and stabilize the solid electrolyte interphase upon the large volume change of phosphorus during cycling. As a result, the phosphorus/graphene nanosheet hybrid nanostructured anode delivers a high reversible capacity of 2077 mAh/g with excellent cycling stability (1700 mAh/g after 60 cycles) and high Coulombic efficiency (>98%). This simple synthesis approach and unique nanostructure can potentially be applied to other phosphorus-based alloy anode materials for sodium-ion batteries.

Polyanthraquinone as a Reliable Organic Electrode for Stable and Fast Lithium Storage.

In spite of recent progress, there is still a lack of reliable organic electrodes for Li storage with high comprehensive performance, especially in terms of long-term cycling stability. Herein, we report an ideal polymer electrode based on anthraquinone, namely, polyanthraquinone (PAQ), or specifically, poly(1,4-anthraquinone) (P14AQ) and poly(1,5-anthraquinone) (P15AQ). As a lithium-storage cathode, P14AQ showed exceptional performance, including reversible capacity almost equal to the theoretical value (260 mA h g(-1); >257 mA h g(-1) for AQ), a very small voltage gap between the charge and discharge curves (2.18-2.14=0.04 V), stable cycling performance (99.4% capacity retention after 1000 cycles), and fast-discharge/charge ability (release of 69% of the low-rate capacity or 64% of the energy in just 2 min). Exploration of the structure-performance relationship between P14AQ and related materials also provided us with deeper understanding for the design of organic electrodes.

Liquid Metal Interfacial Engineering Strategy to Synthesize All-Carbon-Linked Porous Aromatic Frameworks for the Cycloaddition of CO2 with Epoxides.

This study explores the room-temperature synthesis of porous materials and the immobilization of CO2 without the use of metals. The porous aromatic frameworks synthesized at room temperature retain the important functional group structure, and the abundance of carbon-chlorine bonds creates an excellent environment for imidazole linkage. Consequently, a catalyst conducive to the cycloaddition of carbon dioxide is obtained. Hexachloro-p-xylene is explored as the precursor, and a catalyst conducive to carbon dioxide cycloaddition is obtained. The functionalized porous aromatic frameworks (PAF-280-I/B) possess a conversion of 99.6% with a selectivity of 98.9% toward styrene carbonate (SC). The findings of this study can help mitigate the impact of greenhouse gases and enable the production of organic compounds in the circular carbonate platform, turning waste into valuable resources.

A Molten-Salt Method to Synthesize Co9 S8 Embedded, N, S Co-Doped Mesoporous Carbons from Melamine Formaldehyde Resins for Electrocatalytic Hydrogen Evolution Reactions.

We developed a molten salts process to prepare Co9 S8 nanoparticles (NPs) entrapped, S, N co-doped carbons. Cobalt chloride was used as the cobalt source. The melamine-formaldehyde (MF) resin provided the carbon source and nitrogen source, and thiourea provided sulfur source. In addition, common inorganic salts were added as templates to generate pores. The characterization results showed that the prepared materials contained high contents of N, S and Co, and were mesoporous composites. At the same time, the porosity of electrocatalyst depended on the type of salt and the mass ratio of precursor to salt, which further affected the electrocatalytic activity of hydrogen evolution reaction (HER). The best prepared catalyst showed excellent HER performance. The onset overpotential of the catalyst was low (33 mV) and had a small Tafel slope (61.1 mV dec-1 ), in addition to good stability in alkaline media.

New titanium complexes with symmetric or asymmetric cis-9,10-dihydrophenanthrenediamide ligands formed through sequential intramolecular C-C bond-forming reactions.

A series of new titanium(IV) complexes with symmetric or asymmetric cis-9,10-dihydrophenanthrenediamide ligands, cis-9,10-PhenH(2)(NR)(2)Ti(O(i)Pr)(2) [PhenH(2) = 9,10-dihydrophenanthrene, R = 2,6-(i)Pr(2)C(6)H(3) (2a), 2,6-Et(2)C(6)H(3) (2b), 2,6-Me(2)C(6)H(3) (2c)], cis-9,10-PhenH(2)(NR(1))(NR(2))Ti(O(i)Pr)(2) [R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Et(2)C(6)H(3) (2d); R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Me(2)C(6)H(3) (2e)], and [cis-9,10-PhenH(2)(NR(1))(2)][o-C(6)H(4)(CH=NR(2))]TiO(i)Pr [R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Et(2)C(6)H(3) (3a); R(1) = 2,6-(i)Pr(2)C(6)H(3), 2,6-Me(2)C(6)H(3) (3b)], have been synthesized from the reactions of TiCl(2)(O(i)Pr)(2) with o-C(6)H(4)(CH=NR)Li [R = 2,6-(i)Pr(2)C(6)H(3), 2,6-Et(2)C(6)H(3), 2,6-Me(2)C(6)H(3)]. The symmetric complexes 2a-2c were obtained from the reactions of TiCl(2)(O(i)Pr)(2) with 2 equiv of the corresponding o-C(6)H(4)(CH=NR)Li followed by intramolecular C-C bond-forming reductive elimination and oxidative coupling processes, while the asymmetric complexes 2d-2e were formed from the reaction of TiCl(2)(O(i)Pr)(2) with two different types of o-C(6)H(4)(CH=NR)Li sequentially. The complexes 3a and 3b were also isolated from the reactions for complexes 2d and 2e. All complexes were characterized by (1)H and (13)C NMR spectroscopy, and the molecular structures of 2a, 2b, 2e, and 3a were determined by X-ray crystallography.

A solvent-free strategy for synthesis of Co9S8 nanoparticles entrapped, N, S-codoped mesoporous carbon as hydrogen evolution electrocatalyst.

A facile solvent-free method was developed to synthesize Co9S8 nanoparticles entrapped, N, S-codoped mesoporous carbon, which involved two steps, including hand milling and carbonation. This synthetic route did not require any solvent during the entire process. Moreover, no water and/or acid solution were needed to remove the impurity from the calcined samples. The final products had mesoporous structures, as well as high Co, N, and S contents. In details, N and S atoms both doped into the carboneous matrix, and the Co9S8 nanoparticles also dispersed well in the composites. The characterization results revealed that the ratios of the precursors and the calcination temperatures both determined the porosities of the final products, which could further affect the electrocatalytic activities. The optional sample, G2.0T1.0Co0.3-900, revealed excellent electrocatalytic activities for hydrogen evolution reaction (HER) under acidic condition, requiring overpotential of 71 mV to afford a current density of 10 mA cm-2. Additionally, G2.0T1.0Co0.3-900 also showed superior stability and duration.

Bottom-up synthesis of mesoporous germanium as anodes for lithium-ion batteries.

A series of mesoporous germanium materials were synthesized via the self-templating method. Germanium tetrachloride and sodium potassium alloy were utilized as germanium precursor and reducing agent, respectively. The by-products, NaCl and KCl, could be considered as the in-situ templates. The characterization results showed that the mesopores could be obtained, when the salts were removed by water washing. Moreover, the crystalline germanium could also be achieved, when the calcination temperature is as high as 500 °C. However, when the calcination temperatures are 300 °C, the as-received mesoporous germanium materials are amorphous. When evaluated as anode for lithium-ion batteries (LIBs), the obtained mesoporous germanium exhibits outstanding cycling stability, showing a high reversible specific capacity of 803 mA h g-1 after 100 cycles, as well as enhanced rate performance (655 mA h g-1 at 1 C rate).

Co3O4-nanoparticle-entrapped nitrogen and boron codoped mesoporous carbon as an efficient electrocatalyst for hydrogen evolution.

Co3O4-nanoparticle-entrapped nitrogen and boron codoped mesoporous carbon was synthesized via the molten salt method. Melamine formaldehyde resin (MF resin) was used as the nitrogen and carbon precursor, and boric acid was utilized as the boron precursor. Furthermore, cobalt chloride was used as the cobalt precursor and the template for the formation of mesopores, which could also be removed and partly recovered by acid washing. The characterization results revealed that the as-obtained samples possessed mesoporous structures, with high cobalt, boron, and nitrogen content values. For the sample of Co0.65B0.3NC800, the atomic content values of Co, N, and B are 2.3%, 8.87%, and 8.67%, respectively. Moreover, the carbonation temperature and the amount of salt template could both affect the mesoporous structures of the final samples and then affect the electrocatalytic activities for the hydrogen evolution reaction (HER). When the carbonation temperature was 800 °C, the sample of Co0.65B0.3NC800 showed superior performance for the HER under basic conditions, with high current density, low overpotential, and good stability.

Nitrogen and Sulfur Co-Doped Mesoporous Carbon Embedded with Co9 S8 Nanoparticles: Efficient Electrocatalysts for Hydrogen Evolution.

Co9 S8 embedded, N,S co-doepd mesoporous carbon materials were synthesized by adopting CoCl2 as the molten salt. In details, CoCl2 and glucose were used as cobalt and carbon precursors, respectively, and thiourea was utilized as sulfur and nitrogen precursors. This synthetic process involved three steps, including hand-milling, carbonation, and acid leaching. The results of characterization exhibited that the final products had mesoporous structures, which also showed high nitrogen and sulfur contents. Moreover, the Co9 S8 nanoparticles dispersed evenly in the carbonaceous matrix. Furthermore, the calcining temperature could affect the porosities of the final products and the contents of the heteroatoms, which could further determine the electrocatalytic activities of these catalysts. When used as the electrocatalysts for hydrogen evolution reaction, the optimal catalyst, GTCo900, exhibited superior catalytic activities under acidic condition. The overpotential is 62 mV to afford a current density of 10 mA cm-2 . Moreover, it could also reveal excellent stability for 12 h.

Correction: Co3O4-nanoparticle-entrapped nitrogen and boron codoped mesoporous carbon as an efficient electrocatalyst for hydrogen evolution.

Correction for 'Co3O4-nanoparticle-entrapped nitrogen and boron codoped mesoporous carbon as an efficient electrocatalyst for hydrogen evolution' by Duihai Tang et al., Dalton Trans., 2019, DOI: 10.1039/c8dt05033c.

Nitrogen-doped mesoporous carbon-armored cobalt nanoparticles as efficient hydrogen evolving electrocatalysts.

A series of Co nanoparticles embedded, N-doped mesoporous carbons have been synthesized through chelate-assisted co-assembly strategy followed by thermal treatment. The preparation is based on an assembly process, with evaporation of an ethanol-water solution containing melamine formaldehyde resin (MF resin) as carbon source, nitrogen source, and chelating agent. Moreover, F127 and Co(NO3)2 are used as template and metallic precursor, respectively. The Co nanoparticles embedded, N-doped mesoporous carbon annealed at 800 °C (denoted as MFCo800) shows high electrocatalytic activity for hydrogen evolution reaction (HER) with high current density and low overpotential, which has the ability to operate in both acidic and alkaline electrolytes.

Co-entrapped, N-doped mesoporous carbons prepared from melamine formaldehyde resins with CoCl2 as template for hydrogen evolution.

Cobalt-entrapped, nitrogen-doped mesoporous carbon materials have been prepared using melamine formaldehyde resin (MF resin) as precursor and CoCl2 as template. A fraction of CoCl2 can be reduced to Co nanoparticles and wrapped by the nitrogen doped carbon. Meanwhile, the ratio of MF resin to CoCl2 is an important parameter determining the mesoporous structures of the final products. The surface area of the obtained material decreases with the increase in the ratio of MF resin to CoCl2. Electrocatalytic tests show that the obtained catalysts are highly active for hydrogen evolution reaction in both acidic and basic media, achieving a current density of 10 mA cm-2 at 171 and 186 mV under acidic and alkaline conditions, respectively. Additionally, these catalysts also show good long-term stabilities.

Self-Templated Synthesis of Mesoporous Carbon from Carbon Tetrachloride Precursor for Supercapacitor Electrodes.

A high-surface-area mesoporous carbon material has been synthesized using a self-templating approach via reduction of carbon tetrachloride by sodium potassium alloy. The advantage is the reduction-generated salt templates can be easily removed with just water. The produced mesoporous carbon has a high surface area and a narrow pore size distribution. When used as a supercapacitor electrode, this material exhibits a high specific capacitance (259 F g(-1)) and excellent cycling performance (>92% capacitance retention for 6000 cycles).

Phosphorus-Graphene Nanosheet Hybrids as Lithium-Ion Anode with Exceptional High-Temperature Cycling Stability.

A red phosphorus-graphene nanosheet hybrid is reported as an anode material for lithium-ion batteries. Graphene nanosheets form a sea-like, highly electronically conductive matrix, where the island-like phosphorus particles are dispersed. Benefiting from this structure and properties of phosphorus, the hybrid delivers high initial capacity and exhibits promising retention at 60 °C.

Bis(2,2,2-trifluoroethyl) ether as an electrolyte co-solvent for mitigating self-discharge in lithium-sulfur batteries.

Lithium-sulfur batteries suffer from severe self-discharge because of polysulfide dissolution and side reaction. In this work, a novel electrolyte containing bis(2,2,2-trifluoroethyl) ether (BTFE) was used to mitigate self-discharge of Li-S cells having both low- and high-sulfur-loading sulfur cathodes. This electrolyte meaningfully decreased self-discharge at elevated temperature, though differences in behavior of cells with high- and low-sulfur-loading were also noted. Further investigation showed that this effect likely stems from the formation of a more robust protective film on the anode surface.

Tailored synthesis of hierarchical spinous hollow titania hexagonal prisms via a self-template route.

Novel hierarchical spinous hollow titania hexagonal prisms are prepared through a facile fluorine-free self-template route using Ti2O3(H2O)2(C2O4)·H2O (TC) hexagonal prisms as a precursor. The hollowing transformation can be elucidated by the template-free Kirkendall effect, and diverse nanostructures can also be synthesized during the conversion process, such as the spinous core-shell and yolk-shell nanocomposites. The hierarchical hollow microparticles are composed of ultrathin nanobelts of 50-100 nm in length and about 10 nm in thickness, and possess a higher surface area of up to 163 m(2) g(-1) compared with solid microparticles (49 m(2) g(-1)). This type of morphology is of great interest for lithium-ion batteries because of its shorter length for Li(+) transport and better electrode-electrolyte contact.

Mesoporous silica nanoparticles immobilized salicylaldimine cobalt complexes as high efficient catalysts for polymerization of 1,3-butadiene.

We have synthesized a series of nanocatalysts with different sizes (50-200 nm) for polymerization of 1,3-butadiene (Bd) by immobilizing salicylaldimine cobalt complexes on the mesoporous silica nanoparticles (MSNs). The prepared catalysts have been characterized by infrared (IR) spectra, thermal gravimetric analyses (TGAs), chemical composition analysis, nitrogen adsorption-desorption, scanning electron microscope (SEM), and transmission electron microscope (TEM). The nanocatalysts in combination with methylaluminoxane (MAO) show excellent catalytic efficiency in polymerization of 1,3-butadiene. The results reveal that these nanocatalysts also show higher activity than the homogeneous analog of cobalt complex and the same catalyst on bulky mesoporous silica supporting materials. The yield and the molecular weight of the poly-butadiene product depend on the particle size of the catalyst support. This catalysis process is also a facile way to directly synthesize the polymer/silica composite materials.

Transition metal complexes on mesoporous silica nanoparticles as highly efficient catalysts for epoxidation of styrene.

We have synthesized a series of catalysts for epoxidation of styrene by immobilizing salicylaldimine transition metal (copper, manganese, and cobalt) complexes on mesoporous silica nanoparticles (MSNs) with diameters of 120-150 nm. The prepared catalysts are characterized by infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP), CHN elemental analysis, nitrogen adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These catalysts possess excellent catalytic efficiency in epoxidation of styrene when using tert-BuOOH (TBHP) as oxidant. Styrene shows a high conversion (∼99%) as well as epoxide selectivity (∼80%) over Cu-MSN catalysts, and high conversion (∼99%) and moderate epoxide selectivity (∼65%) over Mn-MSN and Co-MSN catalysts. The recycling experiment results indicate that these catalysts maintain catalytic activity even after being used for three cycles. Our results indicate that MSNs can serve as better catalyst supports.

Preparation of hybrid mesoporous silica luminescent nanoparticles with lanthanide(III) complexes and their exhibition of white emission.

We chose dipicolinic acid as a tridentate chelating unit featuring ONO donors to react with lanthanide(III) ions to yield tight and protective N(3)O(6) environments around the lanthanide(III) ions. We immobilized the lanthanide(III)-dipicolinic acid complexes on colloidal mesoporous silica with diameter smaller than 100 nm by a covalent bond grafting technique and obtained nearly monodisperse luminescent Eu-dpa-Si and Tb-dpa-Si functionalized hybrid mesoporous silica nanomaterials. These hybrid nanomaterials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, nitrogen adsorption-desorption, and photoluminescence spectroscopic techniques. The hybrid mesoporous silica nanoparticles exhibit intense emission lines upon UV-light irradiation, owing to the effective intramolecular energy transfer from the chromophore to the central lanthanide Eu(3+) and Tb(3+) ions. Furthermore, the functionalized nanomaterials can be turned to white light materials after annealing at high temperature.