We synthesized a series of carbon‐supported atomic metal‐N‐C catalysts (M‐SACs: M=Mn, Fe, Co, Ni, Cu) with similar structural and physicochemical properties to uncover their catalytic activity trends and mechanisms. The peroxymonosulfate (PMS) catalytic activity trends are Fe‐SAC>Co‐SAC>Mn‐SAC>Ni‐SAC>Cu‐SAC, and Fe‐SAC displays the best single‐site kinetic value (1.65×105 min−1 mol−1) compared to the other metal‐N‐C species. First‐principles calculations indicate that the most reasonable reaction pathway for 1O2 production is PMS→OH*→O*→1O2; M‐SACs that exhibit moderate and near‐average Gibbs free energies in each reaction step have a better catalytic activity, which is the key for the outstanding performance of Fe‐SACs. This study gives the atomic‐scale understanding of fundamental catalytic trends and mechanisms of PMS‐assisted reactive oxygen species production via M‐SACs, thus providing guidance for developing M‐SACs for catalytic organic pollutant degradation.
Nature has created an efficient sterilization model, i.e., the in situ bacterial capture and killing process via bacteriophages. The bacteriophage is a virus with a unique spiny tail foot; in general, it can capture bacteria and subsequently release nucleic acid to achieve replication and kill bacteria. We define this two-steps process as the localized "capture and killing" (LCK) action. Therefore, it is believed that this bioinspired LCK action may provide massive possibilities for developing efficient disinfection strategies as alternatives to conventional clinical antibiotic treatments. Two concepts must be carefully designed and integrated to construct the bionic nanosystem with LCK action. i) Developing the spiky nanostructures to enhance the interactions between nanomaterials and pathogenic bacteria; [11,12] meanwhile, the spiky structure must be mesoporous to load and release bactericidal substances. [13] ii) Second, developing an efficient and robust bactericidal system without using any antibiotics. [14-18] Compared to many traditional bactericidal molecules, antibacterial strategies based on reactive oxygen species (ROS) have been intensively studied. [19] Due to its short life cycle, ROS can only cause irreversible damage to substances immediately around it. This spatially confined activity helps to develop targeted applications as well as guarantee excellent biocompatibility during usage. [20,21] Moreover, the molecular weight of ROS is very Besides the pandemic caused by the coronavirus outbreak, many other pathogenic microbes also pose a devastating threat to human health, for instance, pathogenic bacteria. Due to the lack of broad-spectrum antibiotics, it is urgent to develop nonantibiotic strategies to fight bacteria. Herein, inspired by the localized "capture and killing" action of bacteriophages, a virus-like peroxidase-mimic (V-POD-M) is synthesized for efficient bacterial capture (mesoporous spiky structures) and synergistic catalytic sterilization (metalorganic-framework-derived catalytic core). Experimental and theoretical calculations show that the active compound, MoO 3 , can serve as a peroxocomplex-intermediate to reduce the free energy for catalyzing H 2 O 2 , which mainly benefits the generation of •OH radicals. The unique virus-like spikes endow the V-POD-M with fast bacterial capture and killing abilities (nearly 100% at 16 µg mL-1). Furthermore, the in vivo experiments show that V-POD-M possesses similar disinfection treatment and wound skin recovery efficiencies to vancomycin. It is suggested that this inexpensive, durable, and highly reactive oxygen species (ROS) catalytic active V-POD-M provides a promising broad-spectrum therapy for nonantibiotic disinfection. The global pandemic caused by the outbreak of coronavirus has aroused tremendous attention across broad scientific communities. Besides the coronavirus pandemic, many other pathogenic microbes also pose a devastating threat to human health. For instance, pathogenic bacteria have infected millions of people and caused almos...
oxidation, [3] the oxygen reduction reaction, [4] hydrogen oxidation reaction, [5] and hydrogen evolution reaction (HER). [6] The scarcity and high cost of Pt have necessitated the development of catalytic systems with increased activity, utilization, and durability of Pt atoms. In this respect, the increase of Pt dispersion on supports by downsizing metals to the atomic scale is of significance for maximizing the Pt utilization and consequently increasing the mass activity and turnover frequency (TOF). [7,8] However, in most cases, the electronic properties of the supported Pt atoms are highly dependent on coordination/supporting environments, which have been shown to be crucial for enabling the Pt catalysts with high intrinsic activity. [9] In recent years, abundant efforts have been made to synthesize the atomic Pt catalysts with tailored coordination environments on diverse supports, such as the N/S-doped carbon materials (Pt 1 /NC, [10] PtRuC [11] ), metal oxides (PtCoO, [12] PtFe 2 O 3 [13] ), metal sulfides (PtMoS 2 [14] ), etc. Anchoring Pt atoms by neighboring strong electronegative atoms will lead to a large charge transfer from Pt to coordinated O/N/S atoms, Platinum-based catalysts occupy a pivotal position in diverse catalytic applications in hydrogen chemistry and electrochemistry, for instance, the hydrogen evolution reactions (HER). While adsorbed Pt atoms on supports often cause severe mismatching on electronic structures and HER behaviors from metallic Pt due to the different energy level distribution of electron orbitals.Here, the design of crystalline lattice-confined atomic Pt in metal carbides using the Pt-centered polyoxometalate frameworks with strong PtO-metal covalent bonds is reported. Remarkably, the lattice-confined atomic Pt in the tungsten carbides (Pt doped @WC x , both Pt and W have atomic radii of 1.3 Å) exhibit near-zero valence states and similar electronic structures as metallic Pt, thus delivering matched energy level distributions of the Pt 5d z 2 and H 1s orbitals and similar acidic hydrogen evolution behaviors. In alkaline conditions, the Pt doped @WC x exhibits 40 times greater mass activity (49.5 A mg Pt −1 at η = 150 mV) than the Pt@C because of the favorable water dissociation and H* transport. These findings offer a universal pathway to construct urgently needed atomic-scale catalysts for broad catalytic reactions.
The extensive research into developing new nanomedicines during the past few years has witnessed significant progress in diverse biomedical fields, especially for combating drug resistance in antitumor and antibacterial therapies. Recently, transition-metal-based enzymatic nanoagents (TM-EnzNAs) with catalytic production of reactive oxygen species (ROS) have been designed and intensively explored, which have become powerful nanoplatforms and exciting research frontiers in constructing next-generation nanotherapeutics to combat drug-resistant tumors and bacteria. Here, the focus is on the recent design, fundamental principles, and material chemistries in developing and applications of TM-EnzNAs. At first, the different ROS-producing mechanisms and the key factors to enhance ROS level are carefully concluded, and the analytic methods are systematically summarized. Then, the rationally engineered TM-EnzNAs via different synthetic approaches with high ROS producing efficiencies are comprehensively discussed, especially the catalytic activities, mechanisms, and structure-function relationships. After that, the representative applications of these ROS-catalytic TM-EnzNAs for antitumor and bacterial eradication are summarized in detail. Finally, the primary challenges and future perspectives have also been outlined. It is anticipated new therapeutic insights into combating drug-resistant tumors and bacteria will be provided, and significant new inspiration for designing future enzymatic nanoagents is offered.
MetalN-coordinated centers supported by carbonaceous substrates have emerged as promising artificial metalloenzymes (AMEs) to mimic the biocatalytic effects of their natural counterparts. However, the synthesis of well-defined AMEs that contain different atomic metalN centers but present similar physicochemical and coordination structures remains a substantial challenge. Here, 20 different types of AMEs with similar geometries and welldefined atomic metalN-coordinated centers are synthesized to compare and disclose the catalytic activities, substrate selectivities, kinetics, and reactive oxygen species (ROS) products. Their oxidase (OXD)-, peroxidase (POD)-, and halogen peroxidase (HPO)-mimetic catalytic behaviors are systematically explored. The Fe-AME shows the highest OXD-and HPO-mimetic activities compared to the other AMEs due to its high v max (0.927 × 10 −6 m s −1 ) and low K m (1.070 × 10 −3 m), while the Cu-AME displays the best POD-like performance. Furthermore, theoretical calculation reveals that the ROS-catalytic paths and activities are highly related to the electronic structures of the metal centers. Benefiting from its facile adsorption of H 2 O 2 molecule and lower energy barrier to generating •O 2 − , the Fe-AME displays higher ROS-catalytic performances than the Mn-AME. The engineered AMEs show not only remarkably high ROS-catalytic performances but also provide new guidance toward developing metalN-coordinated biocatalysts for broad application fields.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202200255.
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