Coupling Molecularly Ultrathin Sheets of NiFe-Layered Double Hydroxide on NiCo₂O₄ Nanowire Arrays for Highly Efficient Overall Water-Splitting Activity

Developing efficient but nonprecious bifunctional electrocatalysts for overall water splitting in basic media has been the subject of intensive research focus with the increasing demand for clean and regenerated energy. Herein, we report on the synthesis of a novel hierarchical hybrid electrode, NiFe-layered double hydroxide molecularly ultrathin sheets grown on NiCo₂O₄ nanowire arrays assembled from thin platelets with nickel foam as the scaffold support, in which the catalytic metal sites are more accessible and active and most importantly strong chemical coupling exists at the interface, enabling superior catalytic power toward both oxygen evolution reaction (OER) and additionally hydrogen evolution reaction (HER) in the same alkaline KOH electrolyte. The behavior ranks top-class compared with documented non-noble HER and OER electrocatalysts and even comparable to state-of-the-art noble-metal electrocatalysts, Pt and RuO₂. When fabricated as an integrated alkaline water electrolyzer, the designed electrode can deliver a current density of 10 mA cm^–2 at a fairly low cell voltage of 1.60 V, promising the material as efficient bifunctional catalysts toward whole cell water splitting

Effects of nanosilver and nanozinc incorporated mesoporous calcium-silicate nanoparticles on the mechanical properties of dentin

<div><p>Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for drug delivery and mineralization induction. They can load silver and exhibit significantly antibacterial effects. However, the effects of MCSNs and silver-loaded MCSNs on dentin are unknown. The silver (Ag) and/or zinc (Zn) incorporated MCSNs (Ag-Zn-MCSNs) were prepared by a template method, and their characterizations were tested. Then the nanoparticles were filled into root canals and their effects on the dentin were investigated. Ag-Zn-MCSNs showed characteristics of mesoporous materials and sustained release of ions over time. Ag-Zn-MCSNs adhered well to the root canal walls and infiltrated into the dentinal tubules after ultrasound activation. Ag-Zn-MCSNs showed no significantly negative effects on either the flexural strength or the modulus of elasticity of dentin, while CH decreased the flexural strength of dentin significantly (<i>P</i><0.05). These findings suggested that Ag and Zn can be incorporated into MCSNs using a template method, and the Ag-Zn-MCSNs may be developed into a new disinfectant for the root canal and dentinal tubules.</p></div

Diameter(D), surface area (S_BET), pore volume (V_P), and mean pore size (D_P) of the nanoparticles.

<p>Diameter(D), surface area (S_BET), pore volume (V_P), and mean pore size (D_P) of the nanoparticles.</p

EDS of MCSNs, Ag-MCSNs, Zn-MCSNs, and Ag-Zn-MCSNs.

<p>EDS of MCSNs, Ag-MCSNs, Zn-MCSNs, and Ag-Zn-MCSNs.</p

pH measurement of MCSNs, Ag-MCSNs, Zn-MCSNs, Ag-Zn-MCSNs and CH over time.

<p>pH measurement of MCSNs, Ag-MCSNs, Zn-MCSNs, Ag-Zn-MCSNs and CH over time.</p

Unravelling the origin of multiple cracking in an additively manufactured Haynes 230

In this work, by using multi-scale characterizations from electron channeling contrast imaging (ECCI) to atom probe tomography (APT), we directly evidenced that the massive cracking events in the selective-laser-melted (SLMed) Haynes 230 superalloy are due to the continuous decoration of an M23C6-type thin film at grain boundaries. The high-melting-point nature of the carbide rules out the possibility of liquidation cracking, while the long and straight film surface facilitates stress-induced solid-state cracking. Impurities, Si, Mn and Fe, greatly enhance the cracking susceptibility despite the interesting fact that they are strongly depleted from the carbide. The massive cracking events in the selective-laser-melted Haynes 230 superalloy are due to the continuous decoration of an M23C6 film at grain boundaries, regardless of the detailed cracking modes.</p

TEM images of the nanoparticles.

<p>(A)MCSNs, (B)Ag-MCSNs, (C)Zn-MCSNs, (D)Ag-Zn-MCSNs. Magnified images (a-d) of the selected area (arrows) in A-D.</p

FE-SEM images of the nanoparticles covering the root canal wall and infiltrating the dentinal tubules.

<p>FE-SEM images of the nanoparticles covering the root canal wall and infiltrating the dentinal tubules.</p

Nitrogen adsorption–desorption isotherm test and pore size distribution of MCSNs, Ag-MCSNs, Zn-MCSNs, and Ag-Zn-MCSNs.

<p>Nitrogen adsorption–desorption isotherm test and pore size distribution of MCSNs, Ag-MCSNs, Zn-MCSNs, and Ag-Zn-MCSNs.</p

The drop or rise percentages of flexural strength and modulus of elasticity in CH, MCSNs, Ag-MCSNs, Zn-MCSNs, Ag-Zn-MCSNs.

<p>The drop or rise percentages of flexural strength and modulus of elasticity in CH, MCSNs, Ag-MCSNs, Zn-MCSNs, Ag-Zn-MCSNs.</p