Particulate Sheets Research Articles

Photocatalytic Z-scheme Overall Water Splitting: Insight into Different Optimization Strategies for Powder Suspension and Particulate Sheet Systems.

Achieving solar light-driven photocatalytic overall water splitting is the ideal and ultimate goal for solving energy and environment issues. Photocatalytic Z-scheme overall water splitting has undergone considerable development in recent years; specific approaches include a powder suspension Z-scheme system with a redox shuttle and a particulate sheet Z-scheme system. Of these, a particulate sheet has achieved a benchmark solar-to-hydrogen efficiency exceeding 1.1%. Nevertheless, owing to intrinsic differences in the components, structure, operating environment, and charge transfer mechanism, there are several differences between the optimization strategies for a powder suspension and particulate sheet Z-scheme. Unlike a powder suspension Z-scheme with a redox shuttle, the particulate sheet Z-scheme system is more like a miniaturized and parallel p/n photoelectrochemical cell. In this review, we summarize the optimization strategies for a powder suspension Z-scheme with a redox shuttle and particulate sheet Z-scheme. In particular, attention has been focused on choosing appropriate redox shuttle and electron mediator, facilitating the redox shuttle cycle, avoiding redox mediator-induced side reactions, and constructing a particulate sheet. Challenges and prospects in the development of efficient Z-scheme overall water splitting are also briefly discussed.

Differential Koch Planar Eddy Current Probe Sensitivity Boosting by Iron Particulate Sheet

Differential Koch Planar Eddy Current Probe Sensitivity Boosting by Iron Particulate Sheet

Visible-Light-Driven Photocatalytic Z-Scheme Overall Water Splitting in La5 Ti2 AgS5 O7 -based Powder-Suspension System.

La5 Ti2 Cux Ag1-x S5 O7 (x=0-1) is a type of long-wavelength-responsive oxysulfide photocatalysts for hydrogen evolution and has been demonstrated to enable the Z-scheme water-splitting coupling with oxygen evolution photocatalysts (OEPs) in the particulate sheet. Among La5 Ti2 Cux Ag1-x S5 O7 materials, La5 Ti2 AgS5 O7 was found to have the highest performance on Z-scheme overall water splitting in conjunction with PtOx -WO3 as an OEP and a triiodide/iodide (I3 - /I- ) redox couple as a shuttle electron mediator in a powder-suspension system. Loading Pt/NiS on La5 Ti2 AgS5 O7 benefitted the Z-scheme to achieve an apparent quantum yield of 0.12 % at 420 nm. The results for this powder-suspension system differ from earlier studies on photocatalyst sheet configurations, in which p-type doping and the formation of a solid solution could effectively enhance the water-splitting activity. This work not only demonstrates a La5 Ti2 AgS5 O7 -based Z-scheme water-splitting photocatalyst but also improves the understanding of the difference between particulate sheets and a powder-suspension system available in an optimal strategy for water splitting.

In situ template synthesis of SnO nanoparticles on nickel foam with high electrochemical performance

A solution strategy performed at room temperature was presented for the in situ synthesis of SnO nanoparticles. SnO nanoparticles were prepared through the following sequent procedure: (1) preparation of rod-like Cd(OH)Cl utilizing the reaction between Cd2+ ions and epoxide; (2) production of Sn21Cl16(OH)14O6 template through the cation exchange reaction between Cd(OH)Cl and Sn2+ ions; (3) formation of SnO nanoparticles on nickel foam by the in situ reaction in strong alkaline electrolyte solution before electrochemical measurement. The as-prepared SnO had very small particle size and ordered nanostructure of particulate sheet, therefore resulting in its excellent electrochemical performance including high specific capacitance and high electrochemical stability for the charge-discharge cycle. Hence, the SnO nanoparticles synthesized in this work could be considered as one promising metal oxide for the utilization as electrode material in supercapacitor.

A bioactive metallurgical grade porous silicon-polytetrafluoroethylene sheet for guided bone regeneration applications.

The properties of porous silicon make it a promising material for a host of applications including drug delivery, molecular and cell-based biosensing, and tissue engineering. Porous silicon has previously shown its potential for the controlled release of pharmacological agents and in assisting bone healing. Hydroxyapatite, the principle constituent of bone, allows osteointegration in vivo, due to its chemical and physical similarities to bone. Synthetic hydroxyapatite is currently applied as a surface coating to medical devices and prosthetics, encouraging bone in-growth at their surface and improving osseointegration. This paper examines the potential for the use of an economically produced porous silicon particulate-polytetrafluoroethylene sheet for use as a guided bone regeneration device in periodontal and orthopaedic applications. The particulate sheet is comprised of a series of microparticles in a polytetrafluoroethylene matrix and is shown to produce a stable hydroxyapatite on its surface under simulated physiological conditions. The microstructure of the material is examined both before and after simulated body fluid experiments for a period of 1, 7, 14 and 30 days using Scanning Electron Microscopy. The composition is examined using a combination of Energy Dispersive X-ray Spectroscopy, Thin film X-ray diffraction, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and the uptake/release of constituents at the fluid-solid interface is explored using Inductively Coupled Plasma-Optical Emission Spectroscopy. Microstructural and compositional analysis reveals progressive growth of crystalline, 'bone-like' apatite on the surface of the material, indicating the likelihood of close bony apposition in vivo.

Self-Assembly of CdTe Nanocrystals into Free-Floating Sheets

In their physical dimensions, surface chemistry, and degree of anisotropic interactions in solution, CdTe nanoparticles are similar to proteins. We experimentally observed their spontaneous, template-free organization into free-floating particulate sheets, which resemble the assembly of surface layer (S-layer) proteins. Computer simulation and concurrent experiments demonstrated that the dipole moment, small positive charge, and directional hydrophobic attraction are the driving forces for the self-organization process. The data presented here highlight the analogy of the solution behavior of the two vastly different classes of chemical structures.

Measurement of the Normal-Fluid Velocity in Superfluids

Numerical calculations of (finite temperature) superfluid vortex ring propagation against a particulate sheet show that the solid particle trajectories collapse to a very good approximation to the normal-fluid path lines. We propose an experiment in which, by measuring the solid particles' velocities, direct information about the instantaneous normal-fluid velocity values could be obtained.