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The applications of a variety of bioactive ceramics such as hydroxyapatite (HA) in orthopedics are limited by their insufficient mechanical properties, especially poor fracture toughness. Thus, further extending the clinical applications of these materials warrants the enhancement of their mechanical properties. Although the reinforcement of ceramics by 2D nanomaterials has been well recognized, integrated structural, mechanical, and functional considerations have been neglected in the design and synthesis of such composite materials. Herein, we report the first use of silica‐coated reduced graphene oxide (S‐rGO) hybrid nanosheets to create bioceramic‐based composites with simultaneously enhanced mechanical and biological properties. In the representative HA‐based bioceramic systems prepared by spark plasma sintering, S‐rGO incorporation was found to be more effective for increasing the Young's modulus, hardness, and fracture toughness than the incorporation of uncoated reduced GO (rGO). Furthermore, when assessed with osteoblast‐like MG‐63 cells, such novel materials led to faster cell proliferation and higher cell viability and alkaline phosphatase activity than are generally observed with pure HA; additionally, cells demonstrate stronger affinity to S‐rGO/HA than to rGO/HA composites. The S‐rGO/bioceramic composites are therefore promising for applications in orthopedic tissue engineering, and this research provides valuable insights into the fabrication of silica‐coated hybrid nanosheet‐reinforced ceramics. [ABSTRACT FROM AUTHOR]

It is reported that electron doped n-type SnSe2 nanoplates show promising thermoelectric performance at medium temperatures. After simultaneous introduction of Se deficiency and Cl doping, the Fermi level of SnSe2 shifts toward the conduction band, resulting in two orders of magnitude increase in carrier concentration and a transition to degenerate transport behavior. In addition, all-scale hierarchical phonon scattering centers, such as point defects, nanograin boundaries, stacking faults, and the layered nanostructures, cooperate to produce very low lattice thermal conductivity. As a result, an enhanced in-plane thermoelectric figure of merit ZTmax of 0.63 is achieved for a 1.5 at% Cl doped SnSe1.95 pellet at 673 K, which is much higher than the corresponding in-plane ZT of pure SnSe2 (0.08). [ABSTRACT FROM AUTHOR]

Abstract: It is reported that electron doped n‐type SnSe2 nanoplates show promising thermoelectric performance at medium temperatures. After simultaneous introduction of Se deficiency and Cl doping, the Fermi level of SnSe2 shifts toward the conduction band, resulting in two orders of magnitude increase in carrier concentration and a transition to degenerate transport behavior. In addition, all‐scale hierarchical phonon scattering centers, such as point defects, nanograin boundaries, stacking faults, and the layered nanostructures, cooperate to produce very low lattice thermal conductivity. As a result, an enhanced in‐plane thermoelectric figure of merit ZTmax of 0.63 is achieved for a 1.5 at% Cl doped SnSe1.95 pellet at 673 K, which is much higher than the corresponding in‐plane ZT of pure SnSe2 (0.08). [ABSTRACT FROM AUTHOR]

The manufacture of mechanically strong and biocompatible titania (TiO2) materials is of vital importance for their application as corneal implant skirts. This study was aimed at optimizing the selection of raw powder and sintering conditions for TiO2 ceramics. TiO2 compacts were synthesized from five raw powders, denoted as Altair, Inframat, Alfa, Materion, and Amperit, respectively, by spark plasma sintering using different sintering parameters. The XRD and Raman results confirmed that the anatase TiO2 phase in the Inframat powder had converted completely to rutile TiO2 phase after sintering at 900°C and above. The nanoindentation results indicated that among the five types of TiO2 samples sintered at 1100°C, the Inframat pellets possessed the highest Young's modulus and hardness. Additionally, when Materion samples were employed to study the effects of SPS parameters, a higher sintering temperature in the range of 1100-1300°C decreased the mechanical properties of sintered pellets probably due to the generation of more structural defects. Culture of human corneal stromal fibroblasts on the sintered sample surfaces showed that comparably high cell viability and proliferation were observed on all TiO2 samples except Amperit compared to positive control. Furthermore, cells cultured on Inframat TiO2 sintered in the temperature range of 900-1300°C exhibited viability and formation of focal adhesion complex similar to those on control, and those prepared at 1100°C had significantly higher cell proliferation indices than control. In conclusion, Inframat TiO2 consolidated at 1100°C by SPS was the best formulation for the preparation of mechanically strong and biocompatible Keratoprosthesis skirt. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3502-3513, 2017. [ABSTRACT FROM AUTHOR]

0D transition metal phosphides (TMPs) nanocrystals (NCs)-2D ultrathin black phosphorus (BP) heterostructure (Ni2P@BP) have been synthesized via a facile sonication-assisted exfoliation followed by a solvothermal process. Compared with the bare BP, the specially designed Ni2P@BP architecture can enhance the electrical conductivity (from 2.12 × 102 to 6.25 × 104 S m-1), tune the charge carrier concentration (from 1.25 × 1017 to 1.37 × 1020 cm-3), and reduce the thermal conductivity (from 44.5 to 7.69 W m-1 K-1) at 300 K, which can be considered for multiple applications. As a result, the Ni2P@BP exhibits excellent Li storage properties and high hydrogen evolution reaction electrocatalytic activities. The Ni2P@BP shows improved Li diffusion kinetics (e.g., the Li ions diffusion coefficient increases from 1.14 × 10-14 cm2 s-1 for pure BP nanosheets to 8.02 × 10-13 cm2 s-1 for Ni2P@BP). In addition, the Ni2P@BP electrode sustains hydrogen production with almost unchanged activity over 3000 cycles, which indicates its good chemical stability when operating under strong reducing environment. [ABSTRACT FROM AUTHOR]

Phosphorene, monolayer or few-layer black phosphorus (BP), has recently triggered strong scientific interest for lithium/sodium ion batteries (LIBs/SIBs) applications. However, there are still challenges regarding large-scale fabrication, poor air stability. Herein, we report the high-yield synthesis of phosphorene with good crystallinity and tunable size distributions via liquid-phase exfoliation of bulk BP in formamide. Afterwards, a densely packed phosphorene-graphene composite (PG-SPS, a packing density of 0.6 g cm−3) is prepared by a simple and easily up-scalable spark plasma sintering (SPS) process. When working as anode materials of LIBs, PG-SPS exhibit much improved first-cycle Coloumbic efficiency (60.2%) compared to phosphorene (11.5%) and loosely stacked phosphorene-graphene composite (34.3%), high specific capacity (1306.7 mAh g−1) and volumetric capacity (256.4 mAh cm−3), good rate capabilities (e.g., 415.0 mAh g−1 at 10 A g−1) as well as outstanding long-term cycling life (91.9% retention after 800 cycles at 10 A g−1). Importantly, excellent air stability of PG-SPS over the 60 days observation in maintaining its high Li storage properties can be achieved. On the contrary, 95.2% of BP in PG sample was oxidized after only 10 days exposure to ambience, leading to severe degradation of electrochemical properties. [ABSTRACT FROM AUTHOR]

In this research, NiAl particles modified Al2O3 composites with toughening and crack-healing performances were prepared by spark plasma sintering. The toughening effects as a function of the NiAl particle size and content were systematically investigated. The fracture toughness was increased by 80% compared with pure alumina after incorporation of 1 μm NiAl particles at 15 wt%. A self-healing process of damaged composites induced by indentation was found to occur, mediated by oxidation of NiAl at elevated temperatures with the size of the NiAl particles. Atomic force microscopy was adopted to characterize the crack-healing performance and to explore the healing mechanism under each healing condition. The best crack-healing efficiency of 99.2% was found in the composite containing 1 μm NiAl at 15 wt% that was annealed at 1300°C for 5 h. In addition, the fracture toughness of the composite was further enhanced by 40% after the crack-healing process. These multifunctional ceramic composites may have promising and broad application in areas such as thermal barrier coatings, fuel cell membranes, etc. [ABSTRACT FROM AUTHOR]

In article number 1600453, Qingyu Yan and co‐workers prepare a densely packed phosphorene‐graphene composite (PG‐SPS, a packing density of 0.6 g cm−3) by a simple and easily up‐scalable spark plasma sintering (SPS) process. The composite exhibits high specific capacity and volumetric capacity, good rate capabilities, in additon to outstanding long‐term cycling life, and especially robust air stability in maintaining its high Li storage properties. [ABSTRACT FROM AUTHOR]