Cu,N codoped carbon nanosheets encapsulating ultrasmall Cu nanoparticles for enhancing selective 1,2-propanediol oxidation

In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited oxygen reduction rate and easy C-C cleavage.Given the high economic feasibility of nonnoble metals,i.e.,Cu,in this work,copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles(Cu@Cu-N-C)were developed to realize highly selective of PDO oxidation to LA.The carbon-encapsulated ultrasmall Cu^(0)NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu(Cu-N)sites are responsible for the high oxygen reduction efficacy.Therefore,the performance of catalytic PDO conversion to LA is optimized by a proposed pathway of PDO→hydroxylacetone→lactaldehyde→LA.Specifically,the enhanced LA selectivity is 88.5%,and the PDO conversion is up to 75.1%in an O_(2)-pressurized reaction system(1.0 MPa O_(2)),superior to other Cu-based catalysts,while in a milder nonpressurized system(O_(2)flow rate of 100 mL min-1),a remarkable LA selectivity(94.2%)is obtained with 39.8%PDO conversion,2.2 times higher than that of supported Au nanoparticles(1%Au/C).Moreover,carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.

金基纳米结构光热抗菌研究进展

病原微生物会导致严重感染,并且由于基因突变以及各种耐药机制的作用,多重耐药菌的数量增长对人和动物的生存构成了极大的威胁,引起了人们对抗菌替代解决方案的关注.近年来,由于金纳米结构良好的生物相容性、光热稳定性、高效的光热转化以及易于表面修饰等优点,研究人员致力于设计由光辐射引发的具有可活化抗菌性能的金纳米结构.本文综述了光活性金纳米结构及其在对抗病原菌尤其是耐药菌感染治疗中的应用,揭示了当前技术的基本原理、重要发展、应用前景和局限性.

Selective and effective oxidation of 5-hydroxymethylfurfural by tuning the intermediates adsorption on Co-Cu-CN_(x)

Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these catalysts still suffer from unsatisfactory activity and poor selectivity.A series of N-doped carbon-supported Co-based dual-metal nanoparticles(NPs)have been designed,among which the Co-Cu_(1.4)-CN_(x) exhibits enhanced HMF oxidative activity,achieving FDCA formation rates 4 times higher than that of pristine Co-CN_(x),with 100%FDCA selectivity.Density functional theory(DFT)calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the dband center of Co-Cu_(1.4)-CN_(x),thus reducing the energy barriers for the conversion of HMF to FDCA.Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.

Alternative Copper-Based Single-Atom Nanozyme with Superior Multienzyme Activities and NIR-II Responsiveness to Fight against Deep Tissue Infections

Nanozymes are considered to represent a new era of antibacterial agents,while their antibacterial efficiency is limited by the increasing tissue depth of infection.To address this issue,here,we report a copper and silk fibroin(Cu-SF)complex strategy to synthesize alternative copper single-atom nanozymes(SAzymes)with atomically dispersed copper sites anchored on ultrathin 2D porous N-doped carbon nanosheets(CuN_(x)-CNS)and tunable N coordination numbers in the CuN_(x) sites(x=2 or 4).The CuN_(x)-CNS SAzymes inherently possess triple peroxidase(POD)-,catalase(CAT)-,and oxidase(OXD)-like activities,facilitating the conversion of H_(2)O_(2)and O_(2)into reactive oxygen species(ROS)through parallel POD-and OXD-like or cascaded CAT-and OXD-like reactions.Compared to CuN_(2)-CNS,tailoring the N coordination number from 2 to 4 endows the SAzyme(CuN_(4)-CNS)with higher multienzyme activities due to its superior electron structure and lower energy barrier.Meanwhile,CuN_(x)-CNS display strong absorption in the second near-infrared(NIR-II)biowindow with deeper tissue penetration,offering NIR-II-responsive enhanced ROS generation and photothermal treatment in deep tissues.The in vitro and in vivo results demonstrate that the optimal CuN_(4)-CNS can effectively inhibit multidrug-resistant bacteria and eliminate stubborn biofilms,thus exhibiting high therapeutic efficacy in both superficial skin wound and deep implant-related biofilm infections.

Efficient nanozyme engineering for antibacterial therapy

Antimicrobial resistance(AMR)poses a huge threat to human health.It is urgent to explore efficient ways to suppress the spread of AMR.Antibacterial nanozymes have become one of the powerful weapons to combat AMR due to their enzyme-like catalytic activity with a broad-spectrum antibacterial performance.However,the inherent low catalytic activity of nanozymes limits their expansion into antibacterial applications.In this regard,a variety of advanced chemical design strategies have been developed to improve the antimicrobial activity of nanozymes.In this review,we have summarized the recent progress of advanced strategies to engineer efficient nanozymes for fighting against AMR,which can be mainly classified as catalytic activity improvement,external stimuli,bacterial affinity enhancement,and multifunctional platform construction according to the basic principles of engineering efficient nanocatalysts and the mechanism of nanozyme catalysis.Moreover,the deep insights into the effects of these enhancing strategies on the nanozyme structures and properties are highlighted.Finally,current challenges and future perspectives of antibacterial nanozymes are discussed for their future clinical potential.