Exploring cost-effective catalysts with high catalytic performance and long-term stability has always been a general concern for environment protection and energy conversion. Here, Au nanoparticles (NPs) embedded CuO_x-CeO₂ core/shell nanospheres (Au@CuO_x-CeO₂ CSNs) have been successfully prepared through a versatile one-pot method at ambient conditions. The spontaneous auto-redox reaction between HAuCl₄ and Ce(OH)₃ in aqueous solution triggered the self-assembly growth of micro-/nanostructural Au@CuO_x-CeO₂ CSNs. Meanwhile, the CuO_x clusters in Au@CuO_x-CeO₂ CSNs are capable of improving the anti-sintering ability of Au NPs and providing synergistic catalysis benefits. As a result, the confined Au NPs exhibited extraordinary thermal stability even at a harsh thermal condition up to 700 °C. In addition, before and after the severe calcination process, Au@CuO_x-CeO₂ CSNs can exhibit enhanced catalytic activity and excellent recyclability towards the hydrogenation of p-nitrophenol compared to previously reported nanocatalysts. The synergistic catalysis path between Au/CuO_x/CeO₂ triphasic interfaces was revealed by density functional theory (DFT) calculations. The CuO_x clusters around the embedded Au NPs can provide moderate adsorption strength of p-nitrophenol, while the adjacent CeO₂-supported Au NPs can facilitate the hydrogen dissociation to form H* species, which contributes to achieve the efficient reduction of p-nitrophenol. This study opens up new possibilities for developing high-efficient and sintering-resistant micro-/nanostructural nanocatalysts by exploiting multiphasic systems.

Controlling the cellular interaction and internalization of polymer-modified nanoparticles (NPs) is of central importance to the development of promising nanomedicines. Here, we describe the use of synthetic polypeptides for NP surface coating and regulation of their cellular uptake behaviors by simply switching the conformation and anchoring orientation. Our results show that gold NPs (AuNPs) coated with a helical poly(γ-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)esteryl _L-glutamate) (_L-P(EG₃Glu)₅₀) from the C-terminus ((L-C)-AuNPs) exhibit greater zeta potential and more cellular uptake (2.0–5.5 fold higher) than those coated with the same polypeptide but anchored from the N-terminus ((L-N)-AuNPs), or from both the C- and N-terminus at a 1/1 molar ratio ((L-C/L-N)-AuNPs). A similar orientation-regulated cellular internalization pattern is observed in _D-P(EG₃Glu)₅₀ but not the unstructured _DL-P(EG₃Glu)₅₀-modified AuNPs, suggesting an important and universal role of the helix-derived macrodipole in cellular uptake. Moreover, this orientation-governed internalization is successfully reproduced in P(EG₃Glu)₅₀-coated gold nanorods (AuNRs), and applied to the design of doxorubicin-loaded polypeptide micelles. Simulation study offers time-resolved insights regarding the NP–membrane interactions and membrane remodeling. Thus, our study provides a delicate way of regulating the surface chemistry of NPs and the subsequent NP–cell interactions. Moreover, the results highlight the uniqueness of polypeptides in NP surface engineering, and urge a more careful consideration on the polymer orientation effect.

The catalytic performance of metal nanoparticles is often affected by surface oxidation levels. Instead of post-synthesis oxidation/reduction, we propose an efficient method to modulate the oxidation levels by tuning the composition of bimetallic nanoparticles. Here we report a series of Pt–Re bimetallic nanoparticles synthesized via a facile thermal co-reduction process, with a uniform size of approximately 3 nm. The investigation of the growth of the Pt–Re nanoparticles suggests that the Re atoms were enriched on the surface, as confirmed by X-ray photoelectron spectroscopy. Furthermore, X-ray absorption spectroscopy showed that metallic Re was decreased and high-valency ReO_x species were increased in particles with higher Re/Pt ratios. In the etherification of allylic alcohols catalyzed by Pt–Re nanoparticles of different compositions under ambient conditions, particles with higher Re/Pt ratios exhibited significantly better performances. The highest mass activity of Pt–Re bimetallic nanoparticles (127 μmol·g^-1·s^-1) was more than forty times that of the industrial catalyst CH₃ReO₃ (3 μmol·g^-1·s^-1). The catalytically active sites were associated with ReO_x and could be tuned by adjusting the Pt ratio.

The transition from homogeneous to heterogeneous synthetic chemistry enabled by nanocatalysts necessitates investigations of the reaction mechanism and structure-activity relationships for inorganic nanoparticles and organic substrates. Herein, we report that hydrothermally synthesized ruthenium nanoparticles performed differently in the Se–Se bond activation and selenylation of heterocycles, exhibiting a volcano-shaped relationship between catalytic activity and composition. A synergistic effect was observed for Ru-RuO_x nanocatalysts, with numerous characterizations and density functional theory (DFT) calculations suggesting that a PhSeSePh molecule can initially be adsorbed on the metallic Ru sites and cleaved into two PhSe* species, which subsequently migrate to RuO_x sites and react with the nucleophile to achieve the selenylation of heterocycles.

Considering the development of magnetic resonance imaging (MRI) under ultrahigh magnetic field (> 3 T), the exploration of novel contrast agents (CAs) for ultrahigh field MRI is urgently needed. Herein, we report polyethyleneimine (PEI)-coated TbF₃ nanoparticles (NPs), which were synthesized by a facile solvothermal method, as potential dual-mode CAs for ultrahigh field MRI and X-ray computed tomography (CT). Owing to their strong paramagnetism, the TbF₃ NPs showed excellent transverse relaxivity (395.77 mM^–1·s^–1) and negligible longitudinal relaxivity under an ultrahigh magnetic field (7 T) with a great potential as a T₂-weighted MRI contrast agent. Furthermore, by comparison with the clinically used CT CAs (iohexol), the TbF₃ NPs showed superior X-ray attenuation ability. The practical application for T₂-weighted MRI and CT imaging was demonstrated with an animal model. Moreover, cell cytotoxicity and in vivo toxicity assessments implied the low toxicity of TbF₃ NPs. In summary, the above results indicate that TbF₃ NPs are promising candidates for ultrahigh field MRI and CT dual-mode imaging.