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[Display omitted] The practical photocatalytic application of cadmium sulfide (CdS) has been significantly constrained by fast carrier recombination and significant photocorrosion. Therefore, we developed a three-dimensional (3D) step-by-step (S-scheme) heterojunction using the coupling interface between purple tungsten oxide (W 18 O 49) nanowires and CdS nanospheres. The photocatalytic hydrogen evolution rate of optimized W 18 O 49 /CdS 3D S-scheme heterojunction can reach 9.7 mmol·h−1·g−1, 7.5 and 16.2 times greater than pure CdS (1.3 mmol·h−1·g−1) and 10 wt%-W 18 O 49 /CdS (mechanical mixing, 0.6 mmol·h−1·g−1), proving that the tight S-scheme heterojunction constructed by the hydrothermal method can efficiently enhance the carrier separation. Notably, the apparent quantum efficiency (AQE) of W 18 O 49 /CdS 3D S-scheme heterojunction approaches 7.5% and 3.5% at 370 nm and 456 nm, respectively, which is 7.5 and 8.8 times than pure CdS (1.0% and 0.4%). The produced W 18 O 49 /CdS catalyst also has relative stability of structure and hydrogen production. Additionally, the H 2 evolution rate of W 18 O 49 /CdS 3D S-scheme heterojunction is 1.2 times greater than 1 wt%-platinum (Pt)/CdS (8.2 mmol·h−1·g−1), which indicates that the W 18 O 49 can effectively replace the precious metal for boosting the hydrogen production rate. [ABSTRACT FROM AUTHOR]

[Display omitted] Semiconductor photocatalytic water splitting is a green way to convert solar energy into chemical energy, but the recombination of electron and hole pairs and the low utilization of sunlight restrict the development of photocatalytic technology. By comparing the morphologies and hydrogen production properties of different proportions of solid solutions (Cd x Zn 1- x S), one-dimensional (1D) Cd 0.9 Zn 0.1 S nanorods (NRs) with the best photocatalytic properties are obtained. In addition, 1D W 18 O 49 nanowires are assembled on the surface of 1D Cd 0.9 Zn 0.1 S NRs to construct a novel 1D/1D step-scheme (S-scheme) W 18 O 49 /Cd 0.9 Zn 0.1 S heterojunction photocatalyst. The W 18 O 49 /Cd 0.9 Zn 0.1 S heterojunction expands the optical absorption capacity of Cd 0.9 Zn 0.1 S NRs to provide more energy for the photoexcitation of electrons. The optimal hydrogen production rate of W 18 O 49 /Cd 0.9 Zn 0.1 S NRs with W 18 O 49 content of 9 wt% is as high as 66.3 mmol·h−1·g−1, which is 5.7 times and 1.6 times higher than that of Cd 0.9 Zn 0.1 S NRs and 1 wt% Pt/Cd 0.9 Zn 0.1 S NRs. The apparent quantum efficiency (AQE) of 9 wt% W 18 O 49 /Cd 0.9 Zn 0.1 S reaches 56.0 % and 25.9 % under light wavelength irradiation at 370 and 456 nm, respectively. After the 20 h cycle stability test, the activity of photocatalytic hydrogen evolution does not decrease, due that the severe photo-corrosion of Cd 0.9 Zn 0.1 S NRs is efficiently inhibited. This work not only provides a simple and controllable synthesis method for the preparation of heterojunction structure, but also opens up a new way to improve the hydrogen evolution activity and stability of sulfur compounds. [ABSTRACT FROM AUTHOR]

A simple hard template method and hydrothermal process have been employed to fabricate a self-standing hierarchical porous MnO 2 /graphene film. Thus-constructed electrode materials for binder-free supercapacitors exhibit a high specific capacitance of 266.3 F g −1 at the density of 0.2 A g −1 . Moreover, the two-electrode device demonstrates an excellent rate capability and cycling stability with capacitance retention of 85.1% after 2000 charge–discharge cycles at a current density of 1 A g −1 . The porous nanostructured design can effectively improve the specific surface areas and account for the shorter relaxation time for the electrodes, resulting in a high electrochemical performance. [ABSTRACT FROM AUTHOR]

[Display omitted] The solid fraction of the substrate is expected to influence the bouncing behavior of an impinging droplet, thereby affecting spreading and contact time. Hence, it should be possible to alter the velocity and pressure distribution of impacting droplet, and also affect the impact velocity for droplet penetration right upon impact. We systematically investigate the impact dynamics of water droplets on pillared hydrophobic surfaces with different solid fractions using phase-field simulations. The velocity and pressure distributions of impacting droplets on pillared hydrophobic surfaces with varied Weber numbers and solid fractions are studied. In addition, the influences of the solid fraction on the bouncing behaviors of the impinging droplet, such as the maximum wetting spreading, the maximum impacting depth, and the contact time, are also investigated to further understand the impact event. We show that a three-peak pressure profile appears on the top of the pillared hydrophobic surface during droplet impact by varying the solid fraction of the surface. The first peak is generated by the impact of the droplet itself, while the second peak arises from the droplet recoil impact associated with the dynamic properties of the jet. Moreover, we identify a hitherto unknown third pressure peak related to the hydrodynamic singularity that emerges due to the convergence of the fluid during the droplet rebound. This solid fraction-dependent impacting behavior reveals the intricate interplay between droplet dynamics and the underlying surface characteristics, providing valuable insights into the design and optimization of micro/nano structured hydrophobic surfaces for various applications. [ABSTRACT FROM AUTHOR]

Supermolecular hydrogels were prepared by α-cyclodeatrin (α-CD) and Tyloxapol, which can be considered as an oligomer of the nonionic surfactant polyoxyethylene tert-octylphenyl ether (TX-100) with a polymerization degree below 7. Two carbon materials, graphene oxide (GO) and graphene, were mixed into the α-CD/Tyloxapol hydrogel to adjust the physicochemical properties of hydrogel. In order to get stable graphene dispersion and then mix it with α-CD/Tyloxapol hydrogel, both TX-100 and Tyloxapol were used to disperse graphene for comparison. Interestingly, it can be found that TX-100 could disperse graphene better than Tyloxapol owing to smaller molecular size of TX-100 compared with Tyloxapol. Then, both the α-CD/Tyloxapol/GO and α-CD/Tyloxapol/graphene hydrogels were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, small angle X-ray scattering (SAXS), X-ray diffraction (XRD) and rheological measurements. The results revealed that the addition of carbon materials into α-CD/Tyloxapol hydrogel can change their microstructures and the rheological properties. Furthermore, it can be confirmed that a little amount of carbon materials could induce fluorescence quenching sharply which could be a promising candidate for optical sensor. [ABSTRACT FROM AUTHOR]

Abstract: The interactions of BSA with a series of cationic imidazolium gemini surfactants ([C n -s-C n im]Br2, n =10, 12, 14, s =2, 4, 6), quaternary ammonium surfactants (C12C2C12), and their corresponding monomers ([C12mim]Br and DTAB) are investigated by fluorescence using pyrene as a molecular probe, synchronous fluorescence, circular dichroism (CD), and UV–visible absorption spectra. These surfactants are used to elucidate the effects of surfactant hydrophilic head group, spacer length, and hydrophobic chain length on the conformation of BSA. The results of fluorescence spectra and CD show that the imidazolium gemini surfactants with shorter spacers or with longer hydrophobic chains have a larger effect on BSA unfolding, and the imidazolium gemini surfactant interacts with BSA more strongly than its corresponding monomer and the quaternary ammonium gemini surfactant. These conclusions have been confirmed by the binding constants (Ka ) and binding sites (n) for the BSA/surfactant system. Stern–Volmer quenching constants KSV of cationic surfactants binding to BSA are obtained, indicating that the probable quenching mechanism is initiated by ground-state complex formation rather than by dynamic collision. Moreover, the synchronous fluorescence spectra show that the surfactants mainly interact with tryptophan residues of BSA. [Copyright &y& Elsevier]