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Solvent effects have always been a non-negligible factor for aqueous catalytic reactions, though few studies have been devoted towards the molecular understanding and impact of solvent effects on catalysis. In this work, we investigated ethanol dehydrogenation and C-C bond cleavage over Ir(100) in an aqueous solution using density functional theory calculations with both the implicit and explicit solvent models and transition state theory-based kinetics simulations. The results show that solvent polarization assists the α- and β-dehydrogenation of ethanol on Ir(100) in the aqueous solution and hydrogen bonding also assists the ethanol β-dehydrogenation and C-C bond cleavage in CH

The reaction mechanisms of hydrogen and ethyl acetate formation from ethanol dehydrogenation in the presence of a single Cu atom, Cu2, and Cu13 were studied using density functional theory (DFT) calculations. The rate-limiting step was found to be dependent on the Cu cluster size. The acetaldehyde prefers desorbing from Cu clusters due to its low adsorption energy on Cu, rather than dehydrogenating to acetyl. The vibrational frequencies of the system and temperature also affect the reaction mechanism. The HOMO-LUMO gap of the Cu13 cluster rarely altered by adsorption species while that of a single Cu and Cu2 changed substantially when reactive species adsorbed on a single Cu atom or Cu2 cluster. This work also illustrates that the reaction mechanisms are sensitive to the size of Cu clusters.

Economically advantageous Cu-based catalysts have been widely used for a great number of reactions related to ethanol. However, serious obstacles still remain, such as the high reaction energy barrier and low selectivity for the first step of the dehydrogenation of ethanol. In this study, O-H and α-C-H bond cleavages in ethanol on a Cu3X(111) surface (X= Zr, In, Ag, Au) were carried out using DFT to explore the effect of alloying on the selective and effective dehydrogenation of ethanol. Cu3Zr(111) was found to have superior catalytic performances for dehydrogenation with significantly low reaction barriers for both O-H bond cleavage (0.13 eV) and α-C-H bond cleavage (0.73 eV), which are much lower than the results on Cu(111). Thus this work indicates that alloying Zr can selectively break the O-H bond of ethanol, which cannot be accomplished using Pt, Pd, or Cu catalysts. Meanwhile, through PDOS analysis, Mülliken charge analysis, and d-band center analysis, there are two key fac-tors that contribute to the great improvements on the dehydrogenation catalytic activities of Cu3X(111). Firstly, the specific inherent properties of the second alloyed metal X, including the d-band center, are crucial to the adsorption and activation of ethanol on surfaces. Sec-ondly, the electronic distribution on the surfaces resulting from the difference of electronega-tivity between the metals Cu and X is associated with the dehydrogenation reaction barrier. More electron density around the Cu atoms on these surfaces is more beneficial for dehydro-genation reactions, especially when H atoms were adsorbed stably on the Cu sites.

Accessing the colloidal dynamics non-invasively and continuously during the phase transition of a colloidal system is challenging but critical. Here, we demonstrate the use of spatiotemporal coherence-gated light scattering for studying the internal dynamics of drying colloidal droplets. The continuously acquired signal originates from a picoliter-sized volume located at the droplet-substrate interface. The measurement is non-contact, non-invasive, and label free and permits real-time observations of both optical and mechanical changes in the measurement volume. Additionally, some macroscopic descriptors of the drying process can be constructed from the microscopic measurement, providing ample information of the process. Implemented with an endoscopic-like probe, this system can be easily incorporated into the existing drop profiling instruments, which is potential for the full characterization of dynamic colloidal droplets.

To replace precious Pt-based counter electrodes (CEs) with a low-cost Pt-free catalyst of CEs is still a motivating hotspot to decrease the fabrication cost of dye-sensitized solar cells (DSSCs). Herein, four different V2O3@C composite catalysts were synthesized by pyrolysis of a precursor under N2 flow at 1100 °C and further served as catalytic materials of CEs for the encapsulation of DSSCs. The precursors of V2O3@C composites have been prepared via a sol-gel method using different proportions of V2O5 with soluble starch in a H2O2 solution. Power conversion efficiencies (PCEs) of 3.59, 4.79, 5.15, and 5.06% were obtained from different V2O3@C composites, with soluble starch-to-V2O5 mass ratios (S/V) of 1:2, 1:1, 2:1, and 4:1, respectively, as CEs to reduce iodide/triiodide in DSSCs. The improvement of electrode performance is due to the combined effects on the increased specific surface area and the enhanced conductivity of V2O3@C composite catalysts.

Replacing the expensive Pt catalyst of counter electrodes (CEs) with a low-cost Pt-free catalyst has been regarded as one of the crucial steps for cost effectiveness of dye-sensitized solar cells (DSSCs). Herein, MnWO4 as a binary mixed oxide (MnO–WO3) has been prepared with (NH4)10H2(W2O7)6·xH2O and Mn(NO3)2·4H2O via a facile hydrothermal method. DSSCs using MnWO4 CEs show power conversion efficiency (PCE) of 4.93%. To improve the catalytic activity of MnWO4 CEs further, three proportions of MnWO4@AC mixed oxide composite catalysts have been fabricated via simple physical mixing MnWO4 with activated carbon (AC) by ball-milling. Moreover, the DSSCs with the MnWO4@AC composites CEs generate high PCE of 6.50, 6.45 and 6.12%, respectively, from MnWO4 : AC mass ratios of 1 : 2, 1 : 1 and 2 : 1 for the regeneration of traditional iodide/triiodide (I3−/I−) redox couples, which were superior to the pristine MnWO4, Pt- and AC-based counterpart 4.93%, 4.54% and 2.10% CEs under the same test conditions and method. The favorable performances make MnWO4@AC composites act as a new resource of electro-catalytic Pt-free materials for high-performance CEs in the encapsulation of DSSCs.

Organic long-persistent luminescent materials can be easily quenched in aqueous solutions or air, which limits their wide applications. Here we report novel doped organic crystals to overcome this challenge. The stable LPL performance of this crystalline material is visible for over 8 s and can be maintained for at least three months even in aqueous solution or in air.

The traditional counter electrodes (CEs) catalysts are mainly noble Pt-based materials, but their scarcity and high cost impede their practical applications, especially in dye sensitized solar cells (DSSCs). Hence, identifying Pt-free catalyst materials for CEs have been regarded as one of the crucial steps to improve energy conversion efficiency and cost effectiveness of DSSCs. Herein, a feasible one-step reduction was put forward to prepare V2O3@C composites utilizing V2O5 as metal sources, and the soluble starch as carbon source. The four V2O3@C composite catalysts have successfully been prepared and further were applied to CEs as catalytic materials in the encapsulation of DSSCs. The power conversion efficiencies (PCE) of 2.79, 3.94, 5.13 and 4.97% were respectively obtained from mass ratios of the soluble starch to V2O5 with 1:2, 1:1, 2:1 and 4:1 as counter electrode for the regeneration of I3−/I− redox couples. The enhanced performance can be ascribed to the number of active catalytic sites and the distribution channels on the V2O3@C composites CEs, which was caused by that the larger surface area and higher conductivity of amorphous C from the pyrolyzed carbonization of the soluble starch in the precursor.

Effective C–C bond cleavage is a critical concern in the applications of ethanol technologies. The lack of catalytic efficiency toward complete ethanol oxidation reaction (EOR) has hindered the dev...

Indicative of various pathologies, blood properties are under intense scrutiny. The hemorheological characteristics are traditionally gauged by bulk, low-frequency indicators that average out critical information about the complex, multi-scale, and multi-component structure. In particular, one cannot discriminate between the erythrocytes contribution to global rheology and the impact of plasma. Nevertheless, in their fast stochastic movement, before they encounter each other, the erythrocytes probe the subtle viscoelasticity of their protein-rich environment. Thus, if these short time scales can be resolved experimentally, the plasma properties could be determined without having to separate the blood components; the blood is practically testing itself. This microrheological description of blood plasma provides a direct link between the composition of whole blood and its coagulability status. We present a parametric model for the viscoelasticity of plasma, which is probed by the erythrocytes over frequency ranges of kilohertz in a picoliter-sized volume. The model is validated both

We expand Cauchy’s theorem and demonstrate an invariance property for dynamic media. We demonstrate that details of scattering processes do not affect the relationship between measured correlation times and the intrinsic time-scale of medium’s dynamics.

Oxygen deficient TiO2 has attracted extensive attention owning to its narrow bandgap and high electrical conductivity. In this work, novel yellow TiO2 with hierarchically porous architecture is fabricated by a facile pyrolysis method in air via a biomass template. The obtained yellow TiO2 exhibits interesting lithiation induced activation during cycling, which gives rise to a phase change from poorly crystallized TiO2 to an amorphous phase, accompanied by a colour change from yellow to black. In contrast to the intercalation mechanism reported in most of the literature on the TiO2 anode of LIBs, notably, the reversible redox reaction between Ti3+ and metal Ti can be verified in this case, demonstrating the novel conversion reaction mechanism of the TiO2 electrode. Based on this, the yellow porous TiO2 delivers enhanced electrochemical performance as an anode for LIBs with a superior capacity of 480 mA h g−1 at 5 A g−1 and a high capacity of 206 mA h g−1 at 10 A g−1 after 8000 cycles.

We demonstrate the steady-state reduction of optical density along the path of vortex beams. The adjustable properties of the external field control the temporal and spatial scales of this radial transport of mass.

We demonstrate that intensity statistics is nonstationary in diffusive regimes of waves in reflection from random media. A statistical model based on recurrent scattering and near field coupling is proposed and confirmed experimentally.

To replace precious Pt-based counter electrodes (CEs) with a low-cost Pt-free catalyst of CEs is still a motivating hotspot to decrease the fabrication cost of dye-sensitized solar cells (DSSCs). Herein, four different V2O3@C composite catalysts were synthesized by pyrolysis of a precursor under N2 flow at 1100 °C and further served as catalytic materials of CEs for the encapsulation of DSSCs. The precursors of V2O3@C composites have been prepared via a sol–gel method using different proportions of V2O5 with soluble starch in a H2O2 solution. Power conversion efficiencies (PCEs) of 3.59, 4.79, 5.15, and 5.06% were obtained from different V2O3@C composites, with soluble starch-to-V2O5 mass ratios (S/V) of 1:2, 1:1, 2:1, and 4:1, respectively, as CEs to reduce iodide/triiodide in DSSCs. The improvement of electrode performance is due to the combined effects on the increased specific surface area and the enhanced conductivity of V2O3@C composite catalysts.

Coagulation monitoring relies on in vitro tests where the clot formation is induced using external stimuli. We report an optical method capable of revealing the propensity of coagulation based solely on the natural dynamics of erythrocytes in whole blood. In contrast to traditional techniques, our approach provides means to assess the blood coagulability without the need to chemically trigger the coagulation. Results of correlations with standard clinical methods suggest that this optical assay could be used for continuous management of blood coagulation during clinical procedures.

V2O3@activated carbon (V2O3@C) composite catalysts with different mass ratios have successfully been fabricated using a facile one-step the reduction of ammonium vanadate (NH4VO3) with AC in a high-temperature solid-state reaction. V2O3@C composites were further served as catalytic materials for counter electrodes (CEs) in encapsulation of dye sensitized solar cells (DSSCs). The morphology and microstructure of each V2O3@C composite were determined by scanning electron microscopy and X-ray diffraction. Cyclic voltammetry studies revealed that the V2O3@C composites showed a higher electrocatalytic activity than AC and V2O3 for the reduction of triiodide ions. Electrochemical impedance spectroscopy and Tafel analysis data for the symmetrical cells indicated a lower charge transfer resistance and higher exchange current density for V2O3@C composite than AC and V2O3. The experimental results showed that power conversion efficiencies (PCE) of 4.94, 5.55 and 5.32% were obtained for AC:NH4VO3 mass ratios of 1:3, 2:3 and 4:3 as counter electrode toward the reduction of I3−/I− ions respectively, which were superior to higher than that of AC (2.10%) and V2O3 (3.33%) electrode under the same conditions. The enhanced electrode performance can be ascribed to the combined effects of the relatively larger surface area and higher conductivity of V2O3@C composite catalysts.

A naturally fibrous carbon foam is fabricated by employing fish bones as raw materials. Differing to carbon foams in previous reports, numerous unwoven and cross-linked carbon nanofibers were found to construct the whole foam, exhibiting a hierarchical porosity with interconnected channels and multisize pores. In the meantime, on the basis of the rich organic–inorganic components of fish bones, an N-S-P-O codoping was achieved in carbon foams. Benefiting from the synergistic effects of hierarchically porous fibrous foam and multiple heteroatom doping, the as-obtained samples were employed both as anode and cathode materials in lithium ion hybrid supercapacitors (LIHC), which delivered a superior energy density of 131 Wh kg–1 in 0–4.0 V. Significantly, at an impressive power density of 62000 W kg–1, the energy density of this device can still reach an ultrahigh energy density of 72 Wh kg–1, which presents a state of the art supercapacitors. More importantly, continuously being charged/discharged at a high ...

Fe3+ doping is used to enhance the capacity of polythiophene as supercapacitor electrode and the flexible Fe3+ doped PTh electrode on carbon cloth is prepared with an electrochemical deposition method. The successful doping of Fe3+ is confirmed by IR, XPS, and EDS measurements. The electrochemical performance of the PTh electrode is evaluated using cyclic voltammetry, galvanostatic charge-discharge technique, and electrochemical impedance spectroscopy in acidic aqueous electrolyte. The pristine PTh exhibits specific capacitance of 77.2 F g−1 at a current density of 0.5 A g−1. After Fe3+ doping, the specific capacitance is improved to 108.1 F g−1 and the retention rate also improved from 7.8% to 21.2% after 1000 charge-discharge circles.

Tert-butyl-substituted tetramethylcyclopentadiene [C5HMe 4 Bu] was reacted with Ru3(CO)12 to prepare [(η5-C5Me 4 Bu)Ru(CO)(μ-CO)]2. The complex was characterized by IR, 1H NMR, 13C NMR, elemental analysis, and single-crystal X-ray diffraction. The complex was investigated as a catalyst in the aerobic oxidation of alcohols to the corresponding aldehydes and ketones in the presence of 2,2’,6,6’-tetramethylpiperidine N-oxide (TEMPO) as co-oxidant. The combination of [(η5-C5Me 4 Bu)Ru(CO)(μ-CO)]2 and TEMPO afforded an efficient catalytic system for the aerobic oxidation of a variety of primary and secondary alcohols, giving the corresponding carbonyl compounds in good-to-excellent yields.

Ethanol dehydrogenations on Cu(1 1 1), Cu 3 Pd(1 1 1), and Cu 3 Pt(1 1 1) were studied using density functional theory with a PBE functional. The α-C-H and β-C-H scissions are endothermic on all surfaces while the O-H scission is exothermic on Cu(1 1 1) and Cu 3 Pt(1 1 1) but endothermic on Cu 3 Pd(1 1 1). The ethanol dehydrogenation occurs on Cu(1 1 1) through both α-C-H and O-H scissions but on Cu 3 Pd(1 1 1) and Cu 3 Pt(1 1 1) through only α-C-H scission. Furthermore, alloying Pt or Pd with Cu shows an increase in reaction rate at 493 K by more than 3 orders of magnitude, thus illustrating the promise of alloying Pt or Pd in Cu catalysts for ethanol dehydrogenation.

It is a long-standing belief that, in the diffusion regime, the intensity statistics is always stationary and its probability distribution follows a negative exponential decay. Here, we demonstrate that, in fact, in reflection from strong disordered media, the intensity statistics changes through different stages of the diffusion. We present a statistical model that describes this nonstationary property and takes into account the evolving balance between recurrent scattering and near field coupling. The predictions are further verified by systematic experiments in the optical regime. This statistical nonstationary is akin to the nonequilibrium but steady-state diffusion of particulate systems.

Oxygen deficient TiO

To investigate the alloying effects of the Cu catalyst, we performed extensive density functional theory (DFT) calculations to study the reaction mechanisms of ethanol dimerization to form ethyl acetate (EA) on Cu(1 1 1) and CuM(1 1 1) with M = Pt or Pd. Specifically, thirty-three reactions along the minimum energy reaction pathways were studied by calculating the energy barrier and reaction energy. To evaluate catalytic performance and determine the rate-determining step (RDS), we calculated reaction rate constants based on the harmonic transition state theory. The DFT results showed that the most widely recognized Colley mechanism for ethanol dimerization to form EA should be revised by including CH3CHO hydrogenation to form CH3CH2O. While the first dehydrogenation was found to be the RDS on Cu(1 1 1) and Cu3Pt(1 1 1), CH3CHO hydrogenation was identified to be the RDS on Cu3Pd(1 1 1). Furthermore, Cu3Pt(1 1 1) is about 3 orders of magnitude faster than Cu(1 1 1) and Cu3Pd(1 1 1) for ethanol nonoxidative dehydrogenation and esterification. This work also provides a benchmark for further examination of ethanol dimerization over other Cu alloys.

A lack of comprehensive studies of the C-C bond cleavage in organic molecules hampers the rational design of catalysts for many applications, such as in fuel cells and steam reforming technologies. Employing ethanol on Ir(100) as an example, we studied 14 C-C bond cleavages of various species involved in the ethanol oxidation reaction using density functional theory calculations and used the degree of dehydrogenation (DoDH) of the reactant species as a variable to correlate the C-C bond cleavage barrier and reaction energy. This correlation method was also applied to the dehydrogenation reactions of ethanol on various catalysts, and great insight was obtained. The results show that the C-C cleavage barrier generally decreases with DoDH, with a local minimum around 33.3% DoDH. For reactants having more than 50% DoDH, the C-C cleavage is more ready to take place than the dehydrogenation and can occur at room temperature. Furthermore, the O atom in the reactive species plays a critical role in lowering the C-C bond cleavage barrier. The results provide necessary inputs for kinetic studies of ethanol reactions under operando conditions, where a reaction network beyond the minimum energy pathway is needed. The results will also serve as a benchmark for future studies of the ethanol C-C cleavage on other facets of Ir catalysts or on different catalysts. Furthermore, this work demonstrates that the proposed method opens up a new and effective way of correlating catalytic activities for the C-C bond cleavage involving long-chain alkanes and alcohols.

Ethanol dimerization to form ethyl acetate and hydrogen (EDEH) is the best atomically economic reaction and has also been considered as an environmentally friendly process in ethyl acetate synthesis. Understanding of the catalytic activities for the EDEH while preventing byproduct formation is essential to achieve the total utilization of atoms truly. We performed density functional theory calculations to investigate the EDEH on Cu in the presence of three surfaces, namely Cu(111), Cu(110), and Cu(100). The results show that the rate-limiting step of the EDEH is surface-dependent but temperature-independent at reactions lower than 800 K. The rate-limiting step on Cu(110) is the CH3CHO dehydrogenation to CH3CO, whereas that of Cu(111) and Cu(100) is the ethanol dehydrogenation to CH3CH2O. In the presence of all three surfaces, the EDEH takes place mostly on both Cu(110) and Cu(100), with the rate-limiting step being the dehydrogenation of ethanol to CH3CH2O on Cu(110). We further analyzed the electronic properties of surface Cu atoms and decoupled the electronic and geometric effects. The results indicate that the electronic effect plays a critical role in the three dehydrogenation reactions, whereas the geometric effect mainly affects the C O and H H couplings.

Synthesis of the electrode materials of sodium-ion storage devices from sustainable precursors via green methods is highly desirable. In this work, we fabricated a unique N, O dual-doped biocarbon nanosheet with hierarchical porosity by direct pyrolysis of low-cost cuttlebones and simple air oxidation activation (AOA) technique. With prolonging AOA time, thickness of the carbon sheets could be reduced controllably (from 35 to 5 nm), which may lead to tunable preparation of carbon nanosheets with a certain thickness. Besides, an unexpected increase in N-doping amount from 7.5 to 13.9 atom % was observed after AOA, demonstrating the unique role of AOA in tuning the doped heteroatoms of carbon matrix. This was also the first example of increasing N-doping content in carbons by treatment in air. More importantly, by optimizing the thickness of carbon sheets and heteroatom doping via AOA, superior sodium capacity-cycling retention-rate capability combinations were achieved. Specifically, a current state-of-the-art Na

The copolymerization of CO and styrene catalyzed by Pd/C toward the formation of polyketones (PK)was studied in the N-valeronitrile-N′-methylimidazolium hexafluorophosphate ([C4CNmim]+PF6 -) medium. The synthesized PK was characterized by Fourier transform infrared(FTIR), elemental analysis, 13C-nuclear magnetic resonance (13C-NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The supported ionic liquid film on the surface of Pd/C catalyst can prevent the products from covering the hole of active carbon due to its chemical stability and weak coordination ability with metal ions, and thus efficiently improve the catalytic activity. The effects of different amounts of ionic liquid on the catalytic activity and reusability of the catalyst and the molecular weight of PK were discussed. When the usage of ionic liquid is 10wt% (0.1 g ionic liquid / 1 g active carbon carrier) and the theoretical content of Pd2+ is 5wt% (0.05 g Pd2+/ 1 g active carbon carrier), the highest catalytic activity 2 963.64 gSTCO/(gPd · h) is achieved with the molecular weight and polydispersity index of PK as M n = 9 684, M w = 13 452 and M w/M n = 1.389.

To analyze the unit performance degradation for top heater out-of-service operation condition, two calculation methods were introduced, that was the model based calculation method and the simplified variable operation condition analysis method. A 600MW sub-critical steam turbine unit with air cooled condenser was analyzed using the two introduced methods. It is shown that calculation data got can reflect the redistribution effect on steam flows of the turbine extractions and turbine internals due to the top heater out-of-service, and similar and close calculation results were got from the two methods, and both results were lower than result calculated using the commonly used equivalent enthalpy drop method.