Kuaishe Wang

Magnesium (Mg) and Mg alloys are considered as potential candidates for biomedical applications because of their high specific strength, low density, and elastic modulus, degradability, good biocompatibility and biomechanical compatibility. However, the rapid corrosion rate of Mg alloys results in premature loss of mechanical integrity, limiting their clinical application in load-bearing parts. Besides, the low strength of Mg alloys restricts their further application. Thus, it is essential to understand the characteristics and influencing factors of mechanical and corrosion behavior, as well as the methods to improve the mechanical performances and corrosion resistance of Mg alloys. This paper reviews the recent progress in elucidating the corrosion mechanism, optimizing the composition, and microstructure, enhancing the mechanical performances, and controlling the degradation rate of Mg alloys. In particular, the research progress of surface modification technology of Mg alloys is emphasized. Finally, the development direction of biomedical Mg alloys in the future is prospected.

Abstract 2D molybdenum disulfide (MoS 2 ) is developed as a potential alternative non‐precious metal electrocatalyst for energy conversion. It is well known that 2D MoS 2 has three main phases 2H, 1T, and 1T′. However, the most stable 2H‐phase shows poor electrocatalysis in its basal plane, compared with its edge sites. In this work, a facile one‐step hydrothermal‐driven in situ porousizing of MoS 2 into self‐supporting nano islands to maximally expose the edges of MoS 2 grains for efficient utilization of the active stable sites at the edges of MoS 2 is reported. The results show that such active, aggregation‐free nano islands greatly enhance MoS 2 's hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) bifunctional electrocatalytic activities. At a low overpotential of 248 and 300 mV, the porous MoS 2 nano islands can generate a current density of 10 mA cm −2 in HER and OER, which is much better than typical nanosheet morphology. Surprisingly, the porous MoS 2 nano islands even exhibit better performance than the current commercial RuO 2 catalyst in OER. This discovery will be another effective strategy to promote robust 2H‐phase, instead of 1T/1T′‐phase, MoS 2 to achieve efficient endurable bifunctional HER/OER, which is expected to further replace precious metal catalysts in industry.