Deep Insight of Design,Mechanism,and Cancer Theranostic Strategy of Nanozymes

Since the discovery of enzyme-like activity of Fe3O4 nanoparticles in 2007,nanozymes are becoming the promising substitutes for natural enzymes due to their advantages of high catalytic activity,low cost,mild reaction conditions,good stability,and suitable for large-scale production.Recently,with the cross fusion of nanomedicine and nanocatalysis,nanozyme-based theranostic strategies attract great attention,since the enzymatic reactions can be triggered in the tumor microenvironment to achieve good curative effect with substrate specificity and low side effects.Thus,various nanozymes have been developed and used for tumor therapy.In this review,more than 270 research articles are discussed systematically to present progress in the past five years.First,the discovery and development of nanozymes are summarized.Second,classification and catalytic mechanism of nanozymes are discussed.Third,activity prediction and rational design of nanozymes are focused by highlighting the methods of density functional theory,machine learning,biomimetic and chemical design.Then,synergistic theranostic strategy of nanozymes are introduced.Finally,current challenges and future prospects of nanozymes used for tumor theranostic are outlined,including selectivity,biosafety,repeatability and stability,in-depth catalytic mechanism,predicting and evaluating activities.

Multifunctional Film Assembled from N‑Doped Carbon Nanofiber with Co–N_(4)–O Single Atoms for Highly Efficient Electromagnetic Energy Attenuation

Single-atom materials have demonstrated attractive physicochemical characteristics.However,understanding the relationships between the coordination environment of single atoms and their properties at the atomic level remains a considerable challenge.Herein,a facile waterassisted carbonization approach is developed to fabricate well-defined asymmetrically coordinated Co–N_(4)–O sites on biomass-derived carbon nanofiber(Co–N_(4)–O/NCF)for electromagnetic wave(EMW)absorption.In such nanofiber,one atomically dispersed Co site is coordinated with four N atoms in the graphene basal plane and one oxygen atom in the axial direction.In-depth experimental and theoretical studies reveal that the axial Co–O coordination breaks the charge distribution symmetry in the planar porphyrin-like Co–N_(4) structure,leading to significantly enhanced dielectric polarization loss relevant to the planar Co–N_(4) sites.Importantly,the film based on Co–N_(4)–O/NCF exhibits light weight,flexibility,excellent mechanical properties,great thermal insulating feature,and excellent EMW absorption with a reflection loss of−45.82 dB along with an effective absorption bandwidth of 4.8 GHz.The findings of this work offer insight into the relationships between the single-atom coordination environment and the dielectric performance,and the proposed strategy can be extended toward the engineering of asymmetrically coordinated single atoms for various applications.

A multi-kernel-shell indium selenide@carbon nanosphere enabling high-performance lithium-ion batteries

Indium selenide has garnered significant attention for high volumetric capacities,but is currently plagued by the sluggish charge transfer kinetics,severe volume effect,and rapid capacity degradation that hinder their practical applications.Herein,we design,synthesize,and characterize a multi-kernel-shell structure comprised of indium selenide encapsulated within carbon nanospheres(referred to as m-K-S In_(2)Se_(3)@C)through an integrated approach involving a hydrothermal method followed by a gaseous selenization process.Importantly,experimental measurements and density functional theory calculations confirm that the m-K-S In_(2)Se_(3)@C not only improve the adsorption capability for Li-ions but also lower the energy barrier for Li-ions diffusion.Profiting from numerous contact points,shorter diffusion distances and an improved volume buffering effect,the m-K-S In_(2)Se_(3)@C achieves an 800 mA h g^(−1)capacity over 1000 loops at 1000 mA g^(−1),a 520 mA h g^(−1)capacity at 5000 mA g^(−1)and an energy density of 270 Wh kg^(−1)when coupled with LiFePO4,surpassing most related anodes reported before.Broadly,the m-K-S structure with unique nano-micro structure offers a new approach to the design of advanced anodes for LIBs.

Reveal the nature of particle size effect for CO_(2) reduction over Pd and Au

Small cluster and periodic surface models with low coverages of intermediates are frequently employed to investigate reaction mechanisms and identify active sites on nanoparticles(NPs)in density functional theory(DFT)studies.However,diverse active sites on NPs cannot be sufficiently represented by these simple models,hampering the in-depth insights into the catalytic behavior of NPs.This paper describes the crucial roles of both model and coverage effect on understanding the nature of active sites for CO_(2)reduction over Au and Pd NPs using DFT calculations.Terrace sites exhibit higher selectivity for CO than edge sites on Au NPs,which is opposite to the results on Au periodic surfaces.This contradiction reveals the computational model effect on clarifying active site properties.For Pd catalysts,the coverage effect is more significant.On bare Pd NPs and periodic surfaces,the selectivity for CO at edge sites is nearly identical to that at terrace sites,whereas edge sites display higher selectivity for CO than terrace sites in the case of high CO coverages.Through considering the more realistic models and the coverage effect,we successfully describe the size effect of Au and Pd NPs on CO selectivity.More importantly,this work reminds us of the necessity of reasonable models in DFT calculations.

Research progress on rare earth up-conversion and near-infrared Ⅱ luminescence in biological applications

Rare earth luminescence has attracted widespread attention for several decades, among which nearinfrared(NIR) light-related up-conversion luminescence and NIR-Ⅱ luminescence are widely used in the biomedical field. The NIR-related luminescence is widely studied due to the excellent performance, such as good biocompatibility, deep tissue penetration depth, low self-fluorescence and minimal light damage to organisms. In this review, we mainly introduce the mechanism for rare earth up-conversion luminescence, NIR-Ⅱ luminescence and conclude their advantages compared with traditional luminescence.These excellent priorities provide the basis for NIR-related luminescence bioimaging in vivo. Additionally,we hilglight the scheme for the sensitive detection of substances in organisms and various methods for biological therapy. In spite of the existing research, it is outlined that NIR-related luminescence has great potential to be applied in different aspects, expanding perspectives and future challenges of research in related fields. Based on the current scientific achievements, this review can provide reference for research in the areas mentioned above, expand the research direction and arouse a broad interest in different disciplines to pay attention to rare earth luminescence.

Surface group directed low-temperature synthesis and self-assembly of Al nanostructures for lithium storage

Nanostructured aluminum recently delivers a variety of new applications of the earth-abundant Al resource due to the unique properties,but its controllable synthesis remains very challenging with harsh conditions and spontaneously flammable precursors.Herein,a surface group directed method is developed to efficiently achieve low-temperature synthesis and selfassembly of zero-dimensional(0D)Al nanocrystals over one-dimensional(1D)carbon fibers(Al@CFs)through non-flammable AlCl3 reduction at 70°C.Theoretical calculations unveil surface‒OLi groups of carbon fibers exert efficient binding effect to AlCl3,which guides intimate adsorption and in-situ self-assembly of the generated Al nanocrystals.The distinctive 0D-over-1D Al@CFs provides long 1D conductive networks for electron transfer,ultrafine 0D Al nanocrystals for fast lithiation and excellent buffering effect for volume change,thus exhibiting high structure stability and superior lithium storage performance.This work paves the way for mild and controllable synthesis of Al-based nanomaterials for new high-value applications.

Ultrafine Sn_(4)P_(3)nanocrystals from chloride reduction on mechanically activated Na surface for sodium/lithium ion batteries

Nanostructured metal phosphides are very attractive materials in energy storage and conversion,but their applications are severely limited by complicated preparation steps,harsh conditions and large excess of highly toxic phosphorus source.Here we develop a highly efficient one-step method to synthesize Sn_(4)P_(3)nanostructure based on simultaneous reduction of SnCl_(4)and PCl_(3)on mechanically activated Na surface and in situ phosphorization.The low-toxic PCl3 displays a very high phosphorizing efficiency(100%).Furthermore,this simple method is powerful to control phosphide size.Ultrafine Sn_(4)P_(3)nanocrystals(<5 nm)supported on carbon sheets(Sn_(4)P_(3)/C)are obtained,which is due to the unique bottom-up surface-limited reaction.As the anode material for sodium/lithium ion batteries(SIBs/LIBs),the Sn_(4)P_(3)/C shows profound sodiation/lithiation extents,good phase-conversion reversibility,excellent rate performance and long cycling stability,retaining high capacities of 420 mAh/g for SIBs and 760 mAh/g for LIBs even after 400 cycles at 1.0 A/g.Combining simple and efficient preparation,low-toxic and high-efficiency phosphorus source and good control of nanosize,this method is very promising for low-cost and scalable preparation of high-performance Sn_(4)P_(3)anode.

Fabrication of bilayer Pd-Pt nanocages with sub-nanometer thin shells for enhanced hydrogen evolution reaction

The hydrogen evolution reaction (HER),which generates molecular hydrogen through the electrochemical reduction of water,is an important clean-energy technology.Platinum (Pt) is an ideal material for HER electrocatalysts in terms of low overpotential and fast kinetics.An effective method to improve the atom utilization efficiency of Pt is to fabricate Pt-based core-shell or nanocage structures with ultra-thin walls.This paper describes the construction of bilayer palladium (Pd)-Pt alloy nanocages catalyst with enhanced HER catalytic activity.The nanocages were fabricated by etching away the Pd templates of multishelled nanocubes composed of alternate shells of Pd and Pt with well-defined (100) facets.The bilayer Pd-Pt nanocages with sub-nanometer shells have a high dispersion of the active atoms on the outside and inside surfaces of outer layer and inner layer,respectively.Moreover,the Pd-Pt alloy lowers the overpotential for HER and speeds up the reaction rate of HER due to the synergies between Pd and Pt.The rational design of bilayer nanocages provided a novel route for boosting the atom utilization efficiency of Pt catalysts.