Recent advances in hydrothermal synthesis of facet-controlled CeO2-based nanomaterials

Novel Mesoporous and Multilayered Yb/N-Co-Doped CeO2 with Enhanced Oxygen Storage Capacity

A cubic fluorite-type CeO2 with mesoporous multilayered morphology was synthesized by the solvothermal method followed by calcination in air, and its oxygen storage capacity (OSC) was quantified by the amount of O2 consumption per gram of CeO2 based on hydrogen temperature programmed reduction (H2-TPR) measurements. Doping CeO2 with ytterbium (Yb) and nitrogen (N) ions proved to be an effective route to improving its OSC in this work. The OSC of undoped CeO2 was 0.115 mmol O2/g and reached as high as 0.222 mmol O2/g upon the addition of 5 mol.% Yb(NO3)3∙5H2O, further enhanced to 0.274 mmol O2/g with the introduction of 20 mol.% triethanolamine. Both the introductions of Yb cations and N anions into the CeO2 lattice were conducive to the formation of more non-stoichiometric oxygen vacancy (VO) defects and reducible-reoxidizable Cen+ ions. To determine the structure performance relationships, the partial least squares method was employed to construct two linear functions for the doping level vs. lattice parameter and [VO] vs. OSC/SBET.

Synthesis of Hierarchical Layered Quasi-Triangular Ce(OH)CO3 and Its Thermal Conversion to Ceria with High Polishing Performance

Layered quasi-triangular Ce(OH)CO₃ assembled from primary nanoparticles was synthesized via a solvothermal method and converted into CeO₂ abrasive particles by calcination at 800-1000 °C. With the increase of calcination temperature, the primary particle size increased and the microstructure, mechanical hardness, and chemical activity of the CeO₂ particles changed, thus affecting the polishing performance. The calcined products obtained at 800, 850, and 900 °C maintained the layered edge structure of the Ce(OH)CO₃ precursor and had a relatively high specific surface area and surface Ce³⁺ concentration. The samples calcined at 950 and 1000 °C lost the layered structure due to the large-scale melting of the primary particles, and their surface chemical activity decreased. The polishing experiments on K9 glass showed that, with the calcination temperature rising from 800 to 1000 °C, the material removal rate (MRR) first increased and then decreased sharply. The initial increase of MRR was attributed to the increase of mechanical hardness of the layered quasi-triangular CeO₂, and the subsequent decrease of MRR was related to the decrease in surface chemical activity and disappearance of the layered edge structure. The product calcined at 900 °C had the highest MRR and best surface quality after polishing due to the layered edge structure and optimal match of chemical activity and mechanical hardness.

Metal-based nano-delivery platform for treating bone disease and regeneration

Owing to their excellent characteristics, such as large specific surface area, favorable biosafety, and versatile application, nanomaterials have attracted significant attention in biomedical applications. Among them, metal-based nanomaterials containing various metal elements exhibit significant bone tissue regeneration potential, unique antibacterial properties, and advanced drug delivery functions, thus becoming crucial development platforms for bone tissue engineering and drug therapy for orthopedic diseases. Herein, metal-based drug-loaded nanomaterial platforms are classified and introduced, and the achievable drug-loading methods are comprehensively generalized. Furthermore, their applications in bone tissue engineering, osteoarthritis, orthopedic implant infection, bone tumor, and joint lubrication are reviewed in detail. Finally, the merits and demerits of the current metal-based drug-loaded nanomaterial platforms are critically discussed, and the challenges faced to realize their future applications are summarized.