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Based on thermodynamics of spillover hydrogen storage in Pd-based bimetals@Ti3C2Tx, we report that the debatable topic on catalytic activity and selectivity during hydrogen spillover can be settled through determining adsorption enthalpies of spilled H species.

The site-blocking effect (SBE) of nonelectro-chemical steps (nonECS) gives the sluggish kinetics in alkaline hydrogen evolution reaction (HER), but remains rather challenging in electrocatalysis. Herein, we explored nonECS on the highly amorphized NiMoN/NC(500-R) nanoarrays, in which Ni0.76Mo1.24 and Mo2N with the crystallinity of only 13.3% were embedded into nitrogen-rich derived carbons (NC) at 500oC, then followed by electrochemical surface reconstruction. The amorphization and hydroxylation induce the coupled dual-centers of Ni-Mo species to circumvent SBE through separating H*- and H2-involved elementary steps from nonECS, and deliver efficient transfer of individual species and heavy charge accumulation to actuate the whole HER. Resultantly, the exceptional catalytic activity is demonstrated by ultra-low overpotentials of 5.8 and 200.6mV at 10 and 1000mA cm-2, respectively. Importantly, NiMoN/NC(500-R) survive in lasting alkaline HER for 50 days at 500mA cm-2 almost without degeneration. This work presents the key to get rid of SBE in electrocatalysis, and the inspiration to rationally design the amorphized nanoarrays of electrocatalysts.

The aim of this study is to evaluate the effects of diesel from direct coal liquefaction (DDCL) and diesel from indirect coal liquefaction (DICL) on combustion and emissions. A six-cylinder turbocharged diesel engine fueled with DDCL, DICL, petroleum diesel (PD), 58% DDCL, and 42% DICL blended by volume (BD58) is used. The experiments are carried out at 1400 and 2300rpm engine speeds and various engine loads (10%, 25%, 50%, 75%, and 90% of the full-load). The results show that the brake thermal efficiency (BTE) of PD was higher than that of CTL (the maximum difference was 2%) at medium and high loads. At 10% load of 1400 rpm, the CO, HC and formaldehyde emissions of DDCL are 88.9%, 44.3% and 26.5% higher than those of PD respectively, and the CO, HC, and formaldehyde emissions of DICL are 30.1%, 15.3%, and 15.2% lower than those of PD. The differences among four fuels decrease rapidly with the increase of load. The NOX emissions of PD are the highest due to high nitrogen content (102.3 μg/g) and low hydrogen-carbon (H/C) ratio. The fuel with higher cetane number has less formaldehyde emission at low loads, while the fuel with lower H/C has less formaldehyde emission at high loads. The particle size distribution shows a bimodal shape at different loads and the peak particle size of accumulation mode and nucleation mode all increases with the increase of load. The particulate emission of different fuels from high to low is the order of PD > DDCL > BD58 > DICL. In addition, the emissions of polycyclic aromatic hydrocarbons (PAHs) and toxicity equivalent (TE) of PD are highest at all loads. The proportion of soluble organic fractions (SOF) from DDCL, DICL, and BD58 is higher than that of PD.

The emission of NH3 into atmosphere is seriously harmful for human health and public safety, thus the capture and recovery of NH3 from ammonia emissions is highly desirable. In recent years, many kinds of solid adsorbents have been exploited to absorb NH3. However, these materials do not show the advantages of high uptake capacity and good recyclability at the same time. Here, nontoxic and low cost few-layer BiI3 nanosheets have been prepared from bulk BiI3 powder by a simple and efficient liquid phase exfoliation strategy using green solvents and then applied for the NH3 capture for the first time. The results show that the adsorption capacity of NH3 of BiI3 nanosheets reaches up to 22.6 mmol/g at 1.0 bar and 25 °C, which approaches the record value for NH3 adsorption. Importantly, the NH3 uptake in BiI3 nanosheets is completely reversible and no clear loss in uptake capacity is observed after 10 cycles of adsorption-desorption. Furthermore, the BiI3 nanosheets exhibit remarkable selectivity for the separation of NH3/CO2 at 70 °C with theoretical selectivity coefficient of 700, which is promising for the selective separation of NH3 and CO2 in hot tail gas of some industrial processes. Mechanism studies indicate that such superior NH3 capacity, excellent reversibility and remarkable selectivity are primarily attributed to the Bi3+-NH3 coordination interactions.

The selective semihydrogenation of alkynes is of importance in many industrial applications, but great challenges still remain in the full utilization of noble metals for the catalysis of hydrogen spillover on mixed supports. As Pd0 is chemically loaded on Cu2O/TiO2, this work reports that Pd0 is imparted with a high electron density to dissociate H2 efficiently and the active Cu2O hydride is responsible for the high catalytic activity in spillover semihydrogenations. As compared with inert Pd–Cu2O/SiO2 interfaces, the studies demonstrate that the high chemoselectivity and stereoselectivity originate from the well-defined p–n junctions of Cu2O/TiO2, therein alkynes are adsorbed in their trans configurations and the product is desorbed from them. As catalyzed by 1.3Pd–3.6Cu2O/TiO2 in 1 atm H2 at 30 °C, the semihydrogenations can be completed in 90 min with 97.6% chemoselectivity for phenylacetylene, and in 45 min with 92.4% stereoselectivity for methyl non-2-ynoate. These studies provide new ideas to design and synthesize noble metal-based catalysts through manipulating the interface properties of the mixed supports.

Ti3C2Tx MXene is regarded as a promising material in energy-related applications; however, the overscreening charge effect of the electric double layer on electrified interfaces, along with “inert” F terminations, limits the electrochemical operation efficiencies. Here, we developed a protocol to harvest a coupled conductor through confining in situ 1-ethyl-3-methylimidazolium ([Emim]+) ions into Ti3C2Tx interlayers. The ionic–electronic coupling does not require any external counterions, but activates terminal F and even sub-surface Ti, and endows the conductor with metal-like and ionophilic characteristics. Different from physically preintercalated or adsorbed ions, the resulting chemically confined [Emim]+ ions offer more accessible electroactive sites, faster electron transport in surface redox, and more efficient channels for ion transfer. Hence, the Ti3C2Tx electrodes present high gravimetric capacitance, rate performance and cycling stability. This work highlights the important roles of the coupling in the design and research of mixed ionic–electronic conductors with high electrochemical activity.

In recent years, metal-organic frameworks (MOFs) have been explored as emulsifiers for the fabrication of Pickering emulsions and then used for hybrid material synthesis and interface catalysis. Nevertheless, stimuli-responsive Pickering emulsions stabilized by MOFs have been rarely reported so far, although they are of great importance for fundamental research studies and practical applications. Herein, for the first time, triethylenetetramine (TETA)-functionalized MOFs (ZIF-90/TETA) have been designed, synthesized, and used for fabricating CO2-/N2-response Pickering emulsions. It is shown that even at the ZIF-90/TETA content of 0.25 wt %, the functional MOF can still efficiently emulsify n-hexane and water to form a high internal phase Pickering emulsion. Importantly, the Pickering emulsion can be easily and reversibly switched between emulsification and demulsification by bubbling of CO2 and N2 alternatively at atmospheric pressure. The possible mechanism of the CO2/N2 switchable emulsion is investigated by zeta potential, water contact angle, interfacial tension, 13C NMR spectroscopy, and an optical microscope. It is found that the acid-base reaction of CO2 with TETA anchored on the surface of ZIF-90 leads to the production of hydrophilic ammonium bicarbonate and carbamate, which results in the emulsification of the Pickering emulsion. However, when N2 is bubbled to remove CO2, the reverse reaction takes place to cause the demulsification of the Pickering emulsion. Moreover, the CO2/N2 switchable Pickering emulsion has been successfully used as a microreactor for Knoevenagel reactions to demonstrate a highly efficient integration of chemical reaction, product separation, and ZIF-90/TETA recycling for a sustainable chemical process.

The biorenewable alcohols are identified as the promising energy in fuel cells, but the lack of efficient catalysts limits the electricity output. Here, we chemically grew the PdAg alloy nanoparticles (NPs) on reduced graphene oxide (RGO) to obtain PdxAgy(m)/RGO, and investigated the dependences of peak current densities on the metal loadings (m), Pd mole fractions (x), and sizes. The maximal peak currents of 1.86, 4.88, 14.3 and 13.6 × 104 mA cm−2 mgPd−1 were respectively achieved in the electrooxidation reactions of methanol, ethanol, ethylene glycol and glycerol. It is shown that the interactions of PdAg NPs with RGO can control the catalytic efficiencies through mediating the electronic characteristics of metal NPs and the reactant absorptions. Except the catalysts for methanol oxidation reaction, the efficient catalysis possesses the same lattice structure in PdAg alloys with the optimized m, and gives a common descriptor to select the catalyst with high catalytic activity.

A multifunctional plasma mutation system (MPMS) method was used to create high cordycepin-yielding mutations from wild Cordyceps militaris, which yielded many viable mutants, many of which produced more cordycepin compared to the wild strain. One particular mutant strain (GYS60) produced 7.883 mg/mL, which is much higher than those reported to date and is more than 20 times higher than that of the wild strain, whereas the cordycepin production of another viable mutant (GYS80) was almost zero. The extraction and purification of cordycepin, using the fermentation broth of C. militaris GYS60, was also investigated. Cordycepin was extracted by using AB-8 macroporous resin and purified by using reversed-phase column chromatography. When the sample was adsorbed onto the macroporous resin, 20% ethanol was used as the desorption solvent yielding various fractions. The fractions containing cordycepin were loaded onto a reversed-phase chromatography column packed with octadecyl bonded silica as the stationary phase and ethanol (95%)/acetic acid solution (5%) at pH 6.0 as the mobile phase. The combination of this two-step extraction-purification process yielded cordycepin at 95% purity with a total recovery rate of 90%.

Although significant progress has been made in the synthesis of covalent organic frameworks (COFs) in recent years, the construction of hierarchical pores in such materials remains a great challenge. Herein, we report a facile synthesis of hierarchically porous COFs (HP-COFs) under mild conditions in ionic liquids 1-alkyl-3-methylimidazolium tetrafluoroborates ([Cnmim][BF4], n = 4, 6, 10). It has been found that apart from the inherent micropores, a large mesoporous structure has been produced in the COFs in which the size of pores can be simply tuned by adjusting the alkyl chain length of the ionic liquids. These mesopores have been confirmed by N2 sorption and electron microscopy techniques. Importantly, this approach is applicable for the preparation of various HP-COFs, such as imine and hydrazone based COFs, which are quite difficult to acquire through traditional methods. In addition, these HP-COFs show highly effective catalytic performance for C–C bond formation, especially for large size molecule based C–C coupling reactions in comparison with uni-pore COFs.

The emission of NH

In recent years, metal-organic frameworks (MOFs) have been explored as emulsifiers for the fabrication of Pickering emulsions and then used for hybrid material synthesis and interface catalysis. Nevertheless, stimuli-responsive Pickering emulsions stabilized by MOFs have been rarely reported so far, although they are of great importance for fundamental research studies and practical applications. Herein, for the first time, triethylenetetramine (TETA)-functionalized MOFs (ZIF-90/TETA) have been designed, synthesized, and used for fabricating CO

High performances, cost-effectiveness, and facile preparation of electrode materials are of utmost importance for supercapacitors in practical applications. Herein, Ni(HCO3)2 nanoparticles (NPs) of low cost and environmental friendliness were embedded into polydopamine-reduced graphene oxide (PDA-RGO) networks via cost-effective hydrothermal route. It is shown the conducting PDA can uniformly distributes and robustly immobilizes Ni(HCO3)2 NPs in the nanocomposite while the ionic channels are improved for electrolyte access. Consequently, the as-prepared Ni(HCO3)2-PDA-RGO composite offers the high Faradaic capacity of 870 C g−1 at 0.5 A g−1 and moderate rate capability. Furthermore, the assembled Ni(HCO3)2-PDA-RGO//activated carbon hybrid supercapacitor (HSC) delivers a specific capacity of 192 C g−1 at 0.5 A g−1 within operation voltage window of 1.7 V. The maximum energy density of the HSC reaches to 45.3 Wh kg−1 at a power density of 425 W kg−1, and the initial specific capacity maintains 90.5% after 3000 successive charge-discharge cycles. The high energy density and good cycleability certify the potential of the ternary Ni(HCO3)2-PDA-RGO composite in efficient and long lifetime energy storage systems.

A two-dimensional (2D) nanoporous Ni(OH)2 film was successfully developed from triethanolamine (TEA) as the alkali source and soft template using a scalable hydrothermal technique. The nanostructured Ni(OH)2 film was flexible and translucent, and could be directly compressed on a current collector. Owing to the uniform well-defined morphology and stable structure, the Ni(OH)2 film binder-free electrode displayed a high specific capacity, exceptional rate capability, and admirable cycle life. The specific capacitance was 453.6 mA h g−1 (1633 F g−1) at 0.5 A g−1. The assembled Ni(OH)2//activated carbon (AC) asymmetric supercapacitor (ASC) device had an energy density of 58.7 W h kg−1 at a power density of 400 W kg−1. These prominent electrochemical properties of Ni(OH)2 were attributed to the high electrical conductivity, high surface area, and unique porous architecture. Free tailoring, binder-free, and direct pressing were the most significant achievements of the Ni(OH)2 film in the development of high-performance energy storage devices.

In this study, hot compression tests of (Cu43Zr48Al9)98Y2 bulk metallic glasses (BMGs) were performed, and their microstructure and thermal properties after the deformation were studied to explore the appropriate range of their optimum processing parameters. The experimental results show that the superplastic deformation of (Cu43Zr48Al9)98Y2 bulk metallic glasses depends mainly on the temperature and strain rate. It is suitable for superplastic processing when the alloys are in the state of Newtonian flow and do not crystallise. The appropriate processing parameters of (Cu43Zr48Al9)98Y2 BMGs are the temperatures and strain rates, which are below the “dividing line”. And when the temperature is above 733 K, the strain rate must be >1 × 10−3 s−1.

The nanoplasmonic metal-driven photocatalytic activity depends heavily on the spacing between metal nanoparticles (NPs) and semiconductors, and this work shows that ethylene glycol (EG) is an ideal candidate for interface spacer. Controlling the synthetic systems at pH 3, the composite of Ag NPs with EG-stabilized amorphous TiO2 (Ag/TiO2-3) was synthesized by the facile light-induced reduction. It is verified that EG spacers can set up suitable geometric arrangement in the composite: the twin hydroxyls act as stabilizers to bind Ag NPs and TiO2 together and the nonconductive alkyl chains consisting only of two CH2 are able to separate the two building blocks completely and also provide the shortest channels for an efficient transfer of radiation energies to reach TiO2. Employed as photocatalysts in hydrogen evolution under visible light, amorphous TiO2 hardly exhibits the catalytic activity due to high defect density, whereas Ag/TiO2-3 represents a remarkably high catalytic efficiency. The enhancement mec...

This study proposes a facile solvothermal synthesis of nickel tungstate (NiWO4) nanowires for application as a novel cathode material for supercapacitors. The structure, morphology, surface area and pore distribution were characterized and their capacitive performances were investigated. The results showed that the NiWO4 nanowires synthesized in ethylene glycol solvent could offer a high specific capacitance of 1190 F g−1 at a current density of 0.5 A g−1 and a capacitance retaining ratio of 61.5% within 0.5–10 A g−1. When used as a cathodic electrode of an asymmetric supercapacitor (ASC), the NiWO4 nanowire based device can be cycled reversibly in a high-voltage region of 0–1.7 V with a high specific capacitance of 160 F g−1 at 0.5 A g−1, which therefore contributed to an energy density of 64.2 W h kg−1 at a power density of 425 W kg−1. Moreover, 92.8% of its initial specific capacitance can be maintained after 5000 consecutive cycles (5 A g−1). These excellent capacitive properties make NiWO4 a credible electrode material for high-performance supercapacitors.

Rhodamine B (RhB) has often been used as a model pollutant, but its photocatalytic mechanism is still controversial. Herein, Ag NPs were sandwiched between CdS QDs and amorphous-TiO2 (a-TiO2) with the intent to build a CdS/Ag/a-TiO2 catalyst with highly selective oxidation activity. When rhodamine B (RhB) was used as the model organic compound, the CdS/Ag/a-TiO2 composite can not only modulate radical generation but also improve the conversion ratio of RhB to rhodamine 110 (Rh-110) to as high as 82% at 80 min during the visible-light irradiation. A series of the radical scavenging experiments revealed that CdS/Ag/a-TiO2 composites could modulate the effects of hydroxyl radicals (·OH) and superoxide anion radicals (·O2−) at different reaction stages so that the overoxidation of RhB and Rh-110 were repressed. Therefore, the transient state protection mechanism of selective oxidation of RhB was proposed to explain the reaction selectivity for Rh-110. Although the effects of both ·O2− and ·OH are important during the photocatalytic selective oxidation of RhB, it is shown that the selective oxidation of RhB would be performed when the effect of ·O2− is bigger than the ·OH, if not, RhB would be oxidized unselectively. Meanwhile, this may provide a new strategy for modulating radical generation in the photocatalysis of water phases.

With the aid of TiO 2 and Ag/TiO 2 composites with ultrahigh specific surface areas (about 400 m 2 g −1 ), we demonstrated a facile controlled strategy to adjust the photooxidation activity of Ag/TiO 2 in the photocatalysis degradation process of Rhodamine B (RhB). A series of photocatalysis experiment results indicated that the selective oxidation of RhB could be performed through changing irradiation light. When the as-prepared unannealed Ag/TiO 2 was used as photocatalyst, Rh-110 was produced only under visible light irradiation. Instead, RhB would be oxidized completely under ultraviolet irradiation or using the annealing Ag/TiO 2 . Although there were many photocatalysis degradation mechanisms of RhB in previous literatures, we have not found an appropriate mechanism to explain this phenomenon. Radical-trapping tests indicated that the effect of superoxide anion radical was more important than hydroxyl radical in the forming process of Rh-110, and hence the selective oxidation mechanism of Ag/TiO 2 was suggested according to the role changing of Ag nanoparticles on the composites under visible and ultraviolet irradiation.

This work developed a facile colloidal route to synthesize BH4–-capped PdxAgy nanoparticles (NPs) in water using the reducing ionic liquids of [Cnmim]BH4, and the resulting NPs were prone to form the nanocomposites with [amim]+-modified reduced graphene (RG). The removal of the metal-free inorganic ions of BH4– can create the profoundly exposed interfaces on the PdxAgy NPs during the electrooxidation, and favor the ethanol oxidation reaction (EOR) in lowering energy barrier. The counterions of [Cnmim]+ can gather ethanol, OH– ions, and the reaction intermediates on catalysts, and synergistically interact with RG to facilitate the charge transfer in nanocomposites. The interface-modified RG nanosheets can effectively segregate the PdxAgy NPs from aggregation during the EOR. Along with the small size of 4.7 nm, the high alloying degree of 60.2%, the large electrochemical active surface area of 64.1 m2 g–1, and the great peak current density of 1501 mA cm–2 mg–1, Pd1Ag2@[C2mim]BH4-amimRG nanocomposite exhibi...

CdTe quantum dots (QDs) capped by 1-ethyl-3-methylimidazolium mercaptopropionate ([emim]MP) and the reduced graphene oxide (RG) modified by the amine-terminated ionic liquid ([amim]Br) were synthesized in this work. The coordinating interface interactions between QD and RG render the nanocomposite the excellent electrochemical performances as revealed by cyclic voltammetry, chronocoulometry, and electrical impedance spectroscopy. Based on the experimental results obtained from amimRG, CdTe@MP-amimRG, CdTe@[bmim]MP-amimRG, and CdTe@[emim]MP-amimRG nanocomposites, it is proposed that the synergistic effects between imidazolium rings and graphene are responsible for the enhanced performances. Taking the CdTe@[emim]MP-amimRG nanocomposite as the electrochemical sensor of puerarin, the proposed method demonstrates the linear range over 0.01–4.0 μmol L −1 with the detection limits of 6 nmol L −1 in the aqueous solution (S/N = 3). Moreover, the sensor exhibits fast response time (2s), high sensitivity (74.57 μA μmol L −1 cm −2 ), as well as reproducibility (RSD ≤ 8%), and can maintain the stability at 4 °C for two weeks.

Ternary composite with immobilization of Fe2O3 nanoparticles (NPs) onto porous polydopamine-reduced graphene oxide framework, abbreviated as Fe2O3@PDA-RGO, was fabricated via a simple, scalable and cost-efficient hydrothermal reaction. The as-prepared 3D Fe2O3@PDA-RGO nanocomposite provides a specific surface area of 119.9 m2 g-1 on account of the well-dispersed Fe2O3 NPs (~35 nm) onto the PDA-RGO sheets as spacer. When applied as a special faradic electrode material in negative potential region, Fe2O3@PDA-RGO can offer 169 mA h g-1 (609 F g−1) at 1 A g-1. The fabricated AC//Fe2O3@PDA-RGO asymmetric supercapacitor (ASC) delivers an energy density of 35.8 W h kg-1 (0.94 mW h cm-3) at 800 W kg-1 (21 mW cm-3) and an outstanding cyclic stability (75.7% capacity retention after 10,000 cycles). The good performance of Fe2O3@PDA-RGO in single-electrode and ASC manifests the potential the ternary composite in energy storage devices.

Biomineralization induced by microorganisms has become a hot spot in the field of carbonate sedimentology, however, the mechanisms involved still need to be explored. In this study, the bacterium Bacillus subtilis J2 (GenBank MG575432) was used to induce the precipitation of calcium carbonate minerals at Mg/Ca molar ratios of 0, 3, 6, 9, and 12. Bacillus subtilis J2 bacteria released ammonia to increase pH, but the ammonia released only made the pH increase to 8.25. Carbonic anhydrase was also produced to catalyze the hydration of carbon dioxide, and this process released carbonate and bicarbonate ions that not only increased pH but also elevated carbonate supersaturation. The biominerals formed at a Mg/Ca molar ratio of 0 were spherulitic, elongated, dumbbell-shaped, and irregularly rhombohedral calcite, at a Mg/Ca molar ratio of 3, the biominerals were calcite and aragonite, the weight ratio of calcite decreased from 26.7% to 15.6%, and that of aragonite increased from 73.3% to 84.4% with increasing incubation time. At higher Mg/Ca molar ratios, the biominerals were aragonite, and the crystallinity and thermal stability of aragonite decreased with increasing Mg/Ca molar ratios. FTIR results showed that many organic functional groups were present on/within the biominerals, such as C&ndash, O&ndash, C, N&ndash, H, C=O, O&ndash, H, and C&ndash, H. HRTEM-SAED examination of the ultra-thin slices of B. subtilis J2 bacteria showed that nano-sized minerals with poor crystal structure had grown or been adsorbed on the EPS coating. The EPS of the B. subtilis J2 strain contained abundant glutamic acid and aspartic acid, which could be deprotonated in an alkaline condition to adsorb Ca2+ and Mg2+ ions, this made EPS act as the nucleation sites. This study may provide some references for further understanding of the mechanism of biomineralization induced by microorganisms.

A two-dimensional (2D) nanoporous Ni(OH)

The rich oxygen-vacancies (OVs) on transition metal oxides are favorable for charge storage in supercapacitors, but are subjected to deactivation during charge-discharge cycles. Herein, we report that Co3O4@polydopamine-reduced graphene oxide (Co3O4@PDA-RGO) nanocomposite could relieve the deactivation problem via the self-reviving of OVs. Besides the high specific surface area and ion/electron conductivities, Co3O4@PDA-RGO provides a robust framework to disperse Co3O4 nanorods, and the oxygen atoms in the vicinity of OVs account for 46.2% of oxygen-species. Especially, the resultant OVs can survive the rigorous charge-discharge cycles by virtue of the reversible redox with the aid of PDA-RGO. Given the advantageous structural characteristics, a high specific capacitance of 1562 ​F ​g−1 (781C ​g−1) can be delivered at current densities of 0.5 ​A ​g−1 and retain to 771 ​F ​g−1 (385.5C ​g−1) at 20 ​A ​g−1 ​by the Co3O4@PDA-RGO electrode. Moreover, 91% of its initial capacitance can be maintained after 10,000 consecutive charge-discharge cycles. The asymmetric supercapacitor, assembled by the Co3O4@PDA-RGO electrode and an activated carbon electrode, delivers a high energy density of 46.1 ​Wh kg−1 at 800 ​W ​kg−1. This study paves an efficient avenue to synthesize self-reviving OV on metal oxides for the potential applications in supercapacitors.

The design of green and ingenious strategies for the fabrication of anisotropic nanoparticles and their assembly is particularly important in the advancement of nanoscience and nanotechnology but still remains an enormous challenge. In this work, the Ag films, with variously shaped particles as building blocks, were successfully prepared at the interface of different ionic liquids and water (ILs–H2O) under ambient conditions only by using ILs with different cationic structures. The as-prepared Ag films with different morphologies were characterized and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction. The possible growth mechanisms were also suggested for the formation of differently morphological Ag films at the ILs–H2O interface. The as-obtained Ag films could be directly applied to perform surface-enhanced Raman scattering (SERS) studies. It was found that the nanobelt-contructed Ag films prepared at the inter...

Ionic liquids (ILs) have shown superior performance in the conversion of biomass to 5-hydroxymethylfurfural (5-HMF) as reaction medium and/or catalyst, which is a green platform compound with a wide range of applications in manufacturing fine chemicals and biofuels. Nevertheless, the separation of 5-HMF from ILs is very difficult and becomes a technical bottleneck for IL application in the preparation of 5-HMF. To resolve this problem, understanding the interactions between ILs and 5-HMF is essential. In this work, attenuated total reflectance Fourier transform infrared, 1H nuclear magnetic resonance, and quantum chemistry calculations were combined to investigate the interaction between 5-HMF and each of the eight ILs over the whole composition range. The studied ILs have the same 1-butyl-3-methylimidazolium cation [C4mim]+ but different anions. It was found that interactions between the ILs and 5-HMF were mainly ascribed to the strong hydrogen bonds of 5-HMF with anions of the ILs, and the formation abi...

The present study investigated the flame spread and combustion characteristics of two jatropha oil droplets, droplet A and B. Specifically, the pyrolysis characteristics of jatropha oil were studied using thermogravimetric and differential scanning calorimetry (DSC) analysis. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the components in jatropha oil. Then, the flame spread from droplet A to droplet B and combustion dynamics of two droplets were studied in a constant volume chamber under atmospheric pressure and room temperature (300 K). The effects of normalized droplets spacing S/d0 (2.7–4.9) on flame spread were also studied. The results showed that the combustion of jatropha oil droplet containing three stages: initial expansion stage, quasi-steady combustion stage and micro-explosive combustion stage. Periodic puffing and micro-explosion occurred during micro-explosive combustion stage. This is due to the superheating of low boiling-point components produced by pyrolysis of long-chain fatty acids in jatropha oil. The duration of initial expansion stage increases significantly with the increase of droplet spacing. When the normalized droplet spacing reaches 4.9, the second droplet cannot ignite and reached flame spread limit. Interestingly, the flame spread velocity increase at first and then decrease with increase droplet spacing. This is because the diffusion flame is cooled by unburned droplet when the spacing is relatively small. However, when the spacing is relatively large, the flame spread velocity mainly depends on the duration of second droplet in first stage.

This study proposes a facile solvothermal synthesis of nickel tungstate (NiWO

The nanoplasmonic metal-driven photocatalytic activity depends heavily on the spacing between metal nanoparticles (NPs) and semiconductors, and this work shows that ethylene glycol (EG) is an ideal candidate for interface spacer. Controlling the synthetic systems at pH 3, the composite of Ag NPs with EG-stabilized amorphous TiO

The charge transfer and active sites of metal-free imidazolium-based composites were unveiled by an electrochemical method with high sensitivity and selectivity due to the specific donor–acceptor coupling of imidazolium with NO2−.