Lead halide perovskite nanocrystals (NCs) exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing. However, the poor stability of CsPbX₃ (X = Cl, Br, I) in water is still a challenge to hinder their practical applications. In this work, a facile strategy has been developed for aqueous synthesis of CsPbX₃ nanocrystals, in which L-glutamic acid (L-Glu) has been used to replace oleic acid in the synthetic process. Benefiting from the synergic effects of L-Glu and oleylamine (OAm), CsPbBr₃ nanocrystals (L-Glu/OAm-CsPbBr₃ NCs) with high water stability have been directly prepared under a mild condition at room temperature in water, facilitated by the process of crystal phase transformation from Cs₄PbBr₆ to CsPbBr₃. L-Glu/OAm-CsPbBr₃ NCs exhibit a high quantum yield of 85% and a narrow full width at half maximum of 16 nm, demonstrating their efficient luminescence in water. Typically, L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects, improving the water stability and dispersibility of CsPbBr₃ nanocrystals. Moreover, L-Glu/OAm-CsPbBr₃ NCs exhibit great biocompatibility due to the presence of L-Glu, resulting in their good performance for Hela cell imaging. Thus, we propose a facile and effective method to prepare CsPbBr₃ nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.

Cerium dioxide (CeO₂)-based nanocomposites, as a branch of nanocomposites, are always constructed from CeO₂ combining with other constituents, which exhibit enhanced performance and excellent stability due to their inherent synergistic systems. The modulation of morphology, size, and types of doping of active metals can be achieved by designing the structures, which providing the opportunity to construct diverse CeO₂-based nanocomposites. The optimization of the structure enables the design of new multifunctional CeO₂-based nanocomposites for various applications such as the field of catalysis. In this minireview, we describe the recent development of the nanocomposites based on noble metal-, transition metal-, and metal-organic framework (MOF)-CeO₂, which are synthesized through various scientific and rational methods. Meanwhile, the design, synthesis, and basic working principles for CeO₂-based nanocomposites are also elucidated. In addition, some examples of their catalytic applications such as electrocatalysis, photocatalysis, and thermocatalysis are also discussed. Finally, the structure–activity relationship in guiding the design and synthesis of CeO₂-based nanocomposites is summarized and prospected.

Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts via doping strategy has well-documented for electrochemical water splitting. Herein, a homogeneous structure (denoted as Co/Ce-Ni₃S₂/NF) composed of Co and Ce dual doped Ni₃S₂ nanosheets on nickel foam was synthesized by a facile one-step hydrothermal method. Co and Ce dopants are distributed inside the host sulfide, thereby raising the active sites and the electrical conductivity. Besides, the CeO_x nanoparticles generated by part of the Ce dopants as a cocatalyst further improve the catalytic activity by adding defective sites and enhancing the electron transfer. As a consequence, the obtained Co/Ce-Ni₃S₂/NF electrode exhibits better electrocatalytic activity than single Co or Ce doped Ni₃S₂ and pure Ni₃S₂, with low overpotential (286 mV) at 20 mA·cm^-2, a small Tafel slope and excellent long-term durability in strong alkaline solution. These results presented here not only offer a novel platform for designing transition metal and lanthanide dual-doped catalysts, but also supply some guidelines for constructing catalysts in other catalytic applications.