A Sweet Synthesis of MXenes.

Two-dimensional transition metal carbides/nitrides (MXenes) have shown great promise in various applications. However, mass production of MXenes suffers from the excessive use of toxic fluorine-containing reagents. Herein, a new method was validated for synthesizing MXenes from five MAX ceramics. The method features a minimized (stoichiometric) dosage of F-containing reagent (NaBF4) and polyols (glycerol, erythritol, and xylitol) as the reaction solvent. Due to the sweetness of polyols and the low environmental impact, we refer to this method as a "sweet" synthesis of MXenes. An in-depth molecular dynamics simulation study, combined with experimental kinetic parameters, further revealed that the diffusion of F- in the confined interplanar space is rate-determining for the etching reaction. The expansion of interlayer spacing by polyols effectively reduces the diffusion activation energy of F- and accelerates the etching reaction.

Research on the osteogenic properties of 3D-printed porous titanium alloy scaffolds loaded with Gelma/PAAM-ZOL composite hydrogels.

Although titanium alloy is the most widely used endoplant material in orthopedics, the material is bioinert and good bone integration is difficult to achieve. Zoledronic acid (ZOL) has been shown to locally inhibit osteoclast formation and prevent osteoporosis, but excessive concentrations of ZOL exert an inhibitory effect on osteoblasts; therefore, stable and controlled local release of ZOL may reshape bone balance and promote bone regeneration. To promote the adhesion of osteoblasts to many polar groups, researchers have applied gelatine methacryloyl (Gelma) combined with polyacrylamide hydrogel (PAAM), which significantly increased the hydrogen bonding force between the samples and improved the stability of the coating and drug release. A series of experiments demonstrated that the Gelma/PAAM-ZOL bioactive coating on the surface of the titanium alloy was successfully prepared. The coating can induce osteoclast apoptosis, promote osteoblast proliferation and differentiation, achieve dual regulation of bone regeneration, successfully disrupt the balance of bone remodelling and promote bone tissue regeneration. Additionally, the coating improves the metal biological inertness on the surface of titanium alloys and improves the bone integration of the scaffold, offering a new strategy for bone tissue engineering to promote bone technology.

S-Scheme and Schottky Junction Synchronous Regulation Boost Hierarchical CdS@Nb2O5/Nb2CTx (MXene) Heterojunction for Photocatalytic H2 Production.

Photocatalytic water cracking hydrogen (H2) production is a promising clean energy production technology. Therefore, a ternary CdS@Nb2O5/Nb2CTx (MXene) heterojunction with hierarchical structure was designed to promote photocatalytic H2 evolution. When Na2S/Na2SO3 and lactic acid were used as sacrificial agents, the hydrogen evolution reaction (HER) rates of the optimized photocatalyst were 1501.7 and 2715.8 µmol g-1 h-1, with 12.4% and 26.1% apparent quantum efficiencies (AQE) at 420 nm, respectively. Its HER performance was 10.9-fold higher than that of pure CdS and remained 87% activity after five rounds of cycle tests. Such an enhancement stems from the excellent light absorption properties, tight interfacial contact, fast charge transfer channel, and sufficient active sites. Mechanism analysis demonstrates that S-scheme and Schottky junction synchronous regulation boost hierarchical CdS@Nb2O5/Nb2CTx for photocatalytic H2 production. This work creates possibilities for manufacturing Nb-based MXene photocatalysts for converting solar energy and other applications.