Single Atom Research Articles

Atomically dispersed bimetallic FeZn-N-C with oxidase-like performance: Synthesis, characterization, calculation and activity

The burgeoning interest in single atom catalysts (SACs) stems from their exceptional oxidase-mimicking capabilities, driving substantial advancements in this field. Nevertheless, a critical knowledge gap remains regarding the influence of Zn incorporation on the oxidase-like activity of atomically dispersed Fe-N-C catalysts. This study successfully synthesized and comprehensively characterized three distinct SACs (FeZn SAC-N@C, Fe SAC-N@C, and Zn SAC-N@C) using TEM, HAADF-STEM, XRD, XPS, BET, ICP-MS, and XAFS techniques. Activity assays revealed that FeZn SAC-N@C exhibited the highest oxidase-mimicking activity, with Fe SAC-N@C displaying moderate activity, whereas Zn SAC-N@C did not exhibit oxidase-like behavior. The superior oxidase-like activity of FeZn SAC-N@C is attributed to its enhanced O2 activation capacity, characterized by a high free energy of 0.90 eV in the rate-determining reaction step, surpassing those of Fe SAC-N@C (0.85 eV) and Zn SAC-N@C (0.71 eV). EPR and DFT calculations elucidated the catalytic mechanism of FeZn SAC-N@C, involving the generation of O2− radicals. As a proof-of-concept, FeZn SAC-N@C demonstrates potential as a colorimetric sensor for detecting ascorbic acid and nitrite, achieving a limit of detection of 0.77 μM for ascorbic acid and 0.16 μM for nitrite. These findings open a new avenue for configuring bimetallic atomically dispersed catalysts with oxidase-like activity in future research.

First principles insights into the electronic and magnetic properties of [formula omitted] doped with VIII-group transition metal single atom

Inspired by the unprecedented surface chemical reaction activity of single-atom catalysts (SAC), this research presents a theoretical study on the doping of SnO2(110) surface with transition metal group VIII atoms (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt). Using density functional theory (DFT), the formation energy, electronic structure, charge transfer, and magnetic moments of the SnO2(110) system before and after doping were investigated. The formation energies of the different doped systems vary depending on the doping position. The doping of transition metal (TM) atoms can induce produces both charge transfer and magnetic moment. The charge transfer is largest in the Pd-doped system, with + 0.68 e at the position of the penta-coordinated Sn atom (Sn5c position) and + 0.67 e at the position of the hexa-coordinated Sn atom (Sn6c position), while the Co-doped system exhibits the smallest charge transfer of + 0.19 e (Sn6c position). Fe, Co, Ni, Ru and Os atoms introduce magnetic moments, with the Fe-doped system (Sn5c position) having the highest magnetic moments of 2.91 μB. In the SnO2(110) surface system doped with TM atoms, there are varying degrees of orbital overlap between the TM atoms and their surrounding O atoms. This theoretical work provides valuable insights into the physical properties of metal oxide based single-atom catalysts.

Computational Insight into Transition Metal Atoms Anchored on B2C3P as Single‐Atom Electrocatalysts for Nitrogen Reduction Reaction

AbstractNH3 is not only an important chemical raw material but also a high‐energy storage chemical with zero carbon. Electrocatalytic nitrogen reduction reaction (NRR), which can be driven by clean electric energy under ambient conditions, has become a promising technology for NH3 synthesis due to its environmentally friendly properties. Because of the limitations of low yield and high overpotential, efficient catalysts are urgently needed to solve this problem. In this study, based on density functional theory method and high throughput screening strategy, the NRR was investigated on transition metal single atom anchored to 2D B2C3P surface (TM@B2C3P) as single‐atom catalysts (SACs). The results showed that V@B2C3P and Ti@B2C3P have good catalytic properties, and the limiting potentials were −0.10 and −0.24 V, respectively. Furthermore, the charge density difference and crystal orbital Hamilton population calculations demonstrated that the high catalytic activity can be attributed to the obvious charge transfer between TM@B2C3P and the adsorption intermediates. It is hoped that this work can play a certain role in exploring the application of SACs in NRR.

Rare-earth metal neodymium anchored into graphene as a promising CO2 reduction electrocatalyst by regulating the coordination environment

Carbon-based single atom catalysts (SACs) are promising electrocatalysts in the field of carbon dioxide reduction reactions (CO2RR) due to their high efficiency and environmental friendliness, in which the coordination environment is the key factor determining their intrinsic catalytic activity. Furthermore, rare-earth-based SACs have shown great potential on CO2RR in recent years. Meanwhile, various studies have focused on combining metals with N-doped graphene, which together form potential Mx-Ny-C active sites. This work systematically investigates the impact of varying N/C coordination numbers on Nd atoms in graphene (Nd-NxC6-x, x = 0–5) on the CO2RR reaction mechanism and catalytic performance through density functional theory methods. Detailed Gibbs free energy calculation results indicate that most catalysts undergo a two-electron reduction pathway. For Nd-N3C3, Nd-N3C3–1, Nd-N3C3–2, Nd-N4C2, Nd-N4C2–1, Nd-N4C2–2, and Nd-N5C, HCOOH is the main product, with low UL values of -0.18, -0.17, -0.03, -0.10, -0.11, -0.09, and -0.10 V, respectively. In summary, our research results not only indicate that N atoms with different coordination numbers can improve the product selectivity and catalytic activity of catalysts, but also may provide valuable theoretical insights for studying the application of rare-earth-based SACs.

Single Atom Catalyst for Nitrate-to-Ammonia Electrochemistry.

Various life forms suffer from the negative effects of nitrate when it accumulates in water bodies, which is a major concern in the present day. The removal of nitrate from water bodies is a critical challenge, and the most effective method to achieve that is to change it into ammonia. Ammonia is a clean energy source and a vital input for the fertilizer industry. The Haber-Bosch process, which dominates the industrial production of ammonia, requires a lot of energy. A more sustainable way to produce ammonia is to use nitrate-contaminated water and reduce it to ammonia through electrocatalysis. This review is constituted of amalgamated articles featuring unique conditions that affect the productivity and activity of the transition metal single atom catalyst (TNMSAC) for the electrocatalytic nitrate reduction to ammonia (NRA) reaction. It explores factors such as nitrate ion adsorption, the characteristics of the central electroactive transition metal, the type of coordinating atoms, the impact of potential on stability, and the interplay among single atoms on the selectivity and yield of ammonia gas. In addition, this review also covers advanced concepts such as dual-atom catalysts, dual single atom catalysts, and single atom alloys. The review will provide valuable guidance for enhanced comprehension and strategic designing of TNMSAC for the electrocatalytic conversion of NRA, which will contribute to achieving a green ammonia economy.

Abnormally narrow peaks in TPR-H2 over Pt/CeO2: Experiment and mathematical modelling

The application and development of methods using hydrogen as a gas for testing active surface sites is of great interest in the study of oxide catalysts. In this work a systematic study of Pt/CeO2 catalysts, depending on the platinum loading and calcination temperature was carried out using the method of temperature-programmed reduction by hydrogen (TPR-H2). Experimental TPR-H2 curves demonstrated a complex structure over a wide temperature range, including the presence of abnormally narrow consumption peaks (ANCP-H2) at low temperatures. To describe the kinetics, mathematical modeling of H2 consumption by various platinum active centers has been used, including isolated platinum ions (single atoms) and PtOx clusters of 2D and 3D structures on the surface of ceria nanoparticles. We proposed a criterion that makes it possible to extend the analysis of the TPR-H2 curves for reducible metal-supported oxide systems and unambiguously establish the action of the autocatalytic mechanism in hydrogen consumption. The kinetics of ANCP-H2 by cluster PtOx centers with a half-width of several degrees on the base of the autocatalysis mechanism was described on the base of the proposed model. The simulations show that ANCP-H2 are described by synchronous fast formation of metallic centers that provide a sharp acceleration of H2 consumption. In general, the obtained results establish the fundamental aspects of the H2 interaction with heterogeneous catalysts and are of particular interest in the light of various practical applications of hydrogen energy.

Tip-like copper sites on high curvature supports for non-covalent to covalent interaction tuning in CO2 photoreduction

Single-atom engineering offers a promising method to transform CO2 into high-value chemicals. The local coordination structure design of the metal-support is crucial for overcoming slow reaction kinetics. In this study, Cu single atoms are immobilized on curved Bi12O17Br2 surface to create a tip-like metal site structure named Cutip-Bi12O17Br2. Due to the high curvature Bi12O17Br2 surface with tensile strain, the tip Cu creates significant electronegativity differences between adjacent Bi atomic sites, creating the vigorous polarization centers. The strong charge redistribution character of tip asymmetric Cu-Bi site favor the polarization of CO bond in nonpolar CO2 and adjust the noncovalent to covalent interaction of reaction intermediates. Benefiting from these features, the optimized Cutip-Bi12O17Br2 enhance the CO production rate by a factor of 34 relative to bulk-Bi12O17Br2, reaching a rate of 96.99 μmol g−1 h−1. This work provides a comprehensive understanding of the structural regulation of single-atom on high curvature surface for CO2 photoreduction.

On-Surface Boronation of Porphyrin into a Molecular Dipole.

Functionalized porphyrins by introducing exotic atoms into their central cavities have significant applications across various fields. As unique nanographenes, porphyrins functionalized with monoboron are intriguing, yet their synthesis remains highly challenging. Herein, we present the first on-surface boronation of porphyrin, bonding a single boron atom into the porphyrin's cavity. The boronation is selective, being observed exclusively in molecules featuring a specific aromatic ring-fused structure (ARFS*), not the pristine porphyrin molecule or its other ARFS forms. The boron's bonding geometry is noncentered, transforming the boronated porphyrin into a molecular dipole and imparting a markedly varied electronic structure. Well-ordered two-dimensional dipole arrays are achieved. Upon elevated thermoactivation, intermolecular O-B-O bonds provide robustness and flexibility to the molecular chains. This work demonstrates the high selectivity of on-surface porphyrin boronation and provides an effective strategy for tailoring molecules' electronic structure, producing molecular dipoles, and promoting the robustness and flexibility of molecular chains.

Tetrapyrrolic macrocycles self-organization into floating layers and sensory properties of their Langmuir-Schaefer films

The influence of the chemical structure of the 5,10,15,20-tetraphenylporphyrin (I) and 2-aza-21-carba-5,10,15,20-tetraphenylporphyrin (II) on their supramolecular organization in floating layers at the air/water interface and sensor properties in Langmuir-Schaefer films has been investigated. It was shown that a minor change in the macrocycle structure (namely, the replacement of a single nitrogen atom from the center to the periphery of macrocycle) has a considerable effect on the surface properties and hysteresis processes of the floating layers. Using the Bruster angle microscopy, it was established that both porphyrins aggregate even before the compression of their floating layers begins. The aggregation is more pronounced in porphyrin I. The analysis of hysteresis loops showed that the formation of a floating layer by the modified porphyrin II requires approximately 100 times more energy than for the unmodified porphyrin I. Using the Langmuir-Schaefer (LS) method, the floating layers were transferred onto solid substrates and the resulting thin films were analyzed by atomic force microscopy, scanning electron microscopy, polarization optical microscopy, and spectrophotometry. The combination of these methods revealed a general tendency of the porphyrins to form 3D structures on the surface of LS-films. The study of the basic properties of the porphyrin's LS-films showed that both porphyrins are diprotonated. The protonation process in porphyrin II occurs at a concentration of HClO4 that is 1000 times lower than that observed in porphyrin I. The greater tendency to protonation of porphyrin II is caused by the availability of both nitrogen atoms (the external nitrogen atom located at the macrocycle periphery and the internal nitrogen atom, which becomes more assesible to interactions due to the distortion of the macrocycle). As for the sensor properties of LS-films for iodide ion in aqueous solutions, it was observed that the diprotonated form of porphyrin I exhibited higher sensitivity due to a more developed film surface because of the presence of a greater number of 3D aggregates. The data obtained can be used in the development of efficient pH-controlled thin-film sensor materials for halide ions.

Hydrogen Peroxide Heterolytic Cleavage Induced Gas Phase Photo-Fenton Oxidation of Nitric Oxide.

Nitric oxide (NO) is one of the major air pollutants that may cause ecological imbalance and severe human disease. However, the removal of NO faces challenges of low efficiency, high energy consumption, and production of toxic NO2 byproducts. Herein, we report an efficient *OOH intermediate-involved NO oxidation route with high NO3- selectivity via a gas phase photo-Fenton system. Fe single atoms (Fe SAs)-anchored NH2-UiO-66(Zr) (Fe SAs@NU) was synthesized. The five-coordinated Fe SAs undergo a transient structure reconstitution during the photo-Fenton process, which enables a novel heterolytic cleavage pathway of H2O2 to derive specific ·OOH/·O2- radicals as reactive oxygen species. Therefore, a high NO (550 parts per billion) removal rate of 81% (NO3- selectivity up to 99%) is achieved under visible-light irradiation (>420 nm). This study provides new insight for the high-performance photo-Fenton process via a transient structure reconstitution pathway for the removal of gas phase NOx pollutants.

First principles study of V2CT2-based MXenes materials in oxygen reduction and oxygen evolution reactions

The development of bifunctional ORR/OER electrocatalysts with low cost, high activity and sustainable cycle plays an important role in improving the performance of new green energy storage and conversion devices to alleviate the energy crisis and environmental pollution. As a graphene-like two-dimensional inorganic layered compound with unique electrochemistry, MXenes materials have attracted more and more attention in the field of electrocatalytic applications. In this paper, based on the first-principles calculation method based on density functional theory (DFT) and quantum mechanics, an effective scheme for designing efficient ORR/OER bifunctional electrocatalysts by introducing Pd/Pt single atoms to regulate the electronic structure of V2CT2 (T = O, F) is proposed. Firstly, we discussed the stability of the designed series of single-atom catalysts by calculating the formation energy, binding energy and molecular dynamics simulation. Secondly, by comparing the theoretical overpotentials of these single-atom catalysts for ORR and OER, we found that among the designed SACs, V2CO2-Pd, V2CF2-Pd and V2CO2-VO-Pt are catalysts with good bifunctional catalytic activity for ORR/OER. Our work provides some guidance for the application of MXenes materials in the field of electrocatalysis.

Zn/Cu Bi‐Single‐Atom Nanoplatform: Hexagonal Anti‐Tumor Warrior by ROS Amplification for DOX Resistance Reversal and Immune Activation

AbstractSevere resistance of doxorubicin (DOX) caused by drug efflux and immunosuppression has led to a high treatment failure risk of breast cancer (BC). Compared with the single atom nanozymes, the bi‐single‐atomic nanozymes obtained through sequential single‐atom synthesis strategy in different spaces of the same nanomaterial, can significantly improve the space utilization efficiency and catalytic capacity. In this study, bi‐single‐atom nanozymes (Zn/Cu‐BSAN‐DOX NPs) are designed to reverse BC DOX resistance by causing damage to mitochondria of mesenchymal stem cells (MSCs) and 4T1 cells through reactive oxygen species (ROS) amplification. In situ H2O2 self‐supply is improved by releasing DOX through activating the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs). ROS amplification is triggered by enhanced chemodynamic therapy (CDT) and sonodynamic therapy (SDT) of Zn/Cu‐BSAN, which efficiently reverses the DOX resistance by breaking the hyaluronic acid (HA) barrier and DOX efflux. Furthermore, ROS amplification significantly promotes the immune improvement including DCs maturation, T cell activation, and the polarization of M1 macrophage. In summary, as “hexagonal” anti‐tumor warrior, Zn/Cu‐BSAN‐DOX NPs show great potential for multimodal DOX‐resistant BC therapy, which further expands the new preparation strategy and the clinical anti‐tumor application paradigm of single‐atom nanozymes.

Single Atom‐Engineered 2D Catalytic Nanosheets for Sonocatalytic Suppression of Orthotopic Clear Cell Renal Cell Carcinoma

AbstractClear cell renal cell carcinoma (ccRCC), a prevalent malignant tumor, exhibits resistance to chemotherapy, necessitating advanced therapeutic approaches. Sonocatalytic therapy has emerged as a promising non‐invasive treatment for solid tumors due to its ability to penetrate deep tissue. Herein, the development of single atomic Au‐doped 2D TiO2 nanosheets are presented with oxygen vacancies (Au‐SA/Def‐TiO2, ASDT) for sonocatalytic treatment of ccRCC. Surface defects on TiO2 nanosheets effectively stabilize Au single atomic sites via the Ti‐Au‐Ti structure, enhancing catalytic properties and facilitating reactive oxygen species (ROS) generation by reducing energy barriers and improving electron (e−) and hole (h+) separation. Additionally, ASDT exhibits peroxidase‐like activities, further augmenting ROS production, leading to significant inhibition of tumor growth in subcutaneous and orthotopic ccRCC models under ultrasound irradiation. This study underscores the efficacy of defect engineering for stabilizing single atoms to boost ROS production and achieve effective tumor eradication by the enhanced sonocatalytic effect.

Oxophilic Low‐Coordination Gd‐N3 Single Atom Sites With P‐Enhanced Second Coordination for High‐Performance Al‐Air Batteries

AbstractThe development of efficient rare earth single‐atom (SA) catalysts for the oxygen reduction reaction (ORR) is essential yet challenging for high‐performance aluminum‐air batteries (AABs). This study introduces a concept‐to‐proof strategy for synthesizing a hollow carbon‐supported gadolinium (Gd) SA catalyst using low‐coordination and second‐coordination sphere engineering. In this design, Gd atoms are coordinated to three nitrogen (N) atoms in N‐doped carbon and surrounded by six phosphorus (P) atoms, forming Gd‐N3‐P6 sites. These catalysts demonstrated exceptional ORR performance, achieving a half‐wave potential of 0.895 V and superior durability compared to the commercial Pt/C benchmark. When integrated into AABs, they delivered impressive performance, with a peak power density of 257 mW/cm2 and an energy density of 2916 Wh/kg, alongside enhanced cycling stability. In situ characterization and theoretical calculations revealed that the strategic placement of P atoms in the second coordination sphere significantly enhanced the valence state of the Gd site. This enhancement improved the adsorption capacity for O2 and H2O while facilitating the rapid desorption of *OH intermediates during the ORR. This study offers valuable insights into the development of cost‐effective ORR catalysts, emphasizing the significance of modulating the local coordination environment of metal SA sites.

Cu-TM (Mn, Fe, Ni) dual-atom vs. Pt single atom: TM atoms modulate the electronic structure of Cu sites supported on melamine aerogel to enhance the catalytic purification performance of CH3SH

Despite the high atomic utilization and unique electronic properties of single-atom catalysts (SACs), the single active site to some extent limits the rapid and stable execution of complex reactions involving multiple steps and intermediates on the SACs surface. To address this issue, dual-atom catalysts (DACs) have emerged. The specific spatial proximity enables a synergistic effect between the diatomic pairs, significantly promoting catalytic reactions, though the exact synergistic mechanisms remain to be explored. In this work, we successfully constructed Cu single-atom (Cu-MA) and CuTM (transition metal, TM = Mn, Fe, Ni) dual-atom (CuTM-MA) catalysts on the surface of melamine aerogel (MA) via the impregnation method. Additionally, single-atom catalysts with different Pt loadings (0.5 %, 1 %, and 2 %) (Pt-MA) were synthesized to compare the CH3SH decomposition activity with that of CuTM-MA. Experimental results showed that CuTM-MA significantly outperformed Cu-MA and even rivaled Pt-MA at high temperatures. Utilizing Cu K-edge XAFS, we found that the presence of TM not only enhanced the stability of Cu atoms on the MA surface, preventing aggregation at high temperatures to some extent, but also effectively modulated the electronic structure of Cu atoms, promoting electron transfer from Cu to TM, thus achieving a significant enhancement in catalytic activity.

Enhancing Activity and Stability of Pd-on-TiO2 Single-Atom Catalyst for Low-Temperature CO Oxidation through in Situ Local Environment Tailoring.

The development of efficient Pd single-atom catalysts for CO oxidation, crucial for environmental protection and fundamental studies, has been hindered by their limited reactivity and thermal stability. Here, we report a thermally stable TiO2-supported Pd single-atom catalyst that exhibits enhanced intrinsic CO oxidation activity by tunning the local coordination of Pd atoms via H2 treatment. Our comprehensive characterization reveals that H2-treated Pd single atoms have reduced nearest Pd-O coordination and form short-distanced Pd-Ti coordination, effectively stabilizing Pd as isolated atoms even at high temperatures. During CO oxidation, partial replacement of the Pd-Ti coordination by O or CO occurs. This unique Pd local environment facilitates CO adsorption and promotes the activity of the surrounding oxygen species, leading to superior catalytic performance. Remarkably, the turnover frequency of the H2-treated Pd single-atom catalyst at 120 °C surpasses that of the O2-treated Pd single-atom catalyst and the most effective Pd/Pt single-atom catalysts by an order of magnitude. These findings open up new possibilities for the design of high-performance single-atom catalysts for crucial industrial and environmental applications.

Ruthenium atoms anchored on oxygen-modified molybdenum disulfide with strong interfacial coupling as efficient and stable catalysts for lithium–oxygen batteries

Rechargeable non-aqueous lithium-oxygen batteries (LOBs) have garnered increasing attention owing to their high theoretical energy density. However, their slow cathodic kinetics hinder efficient battery reactions. Nanoscale catalysts can effectively enhance electrocatalytic activity and atomic utilization efficiency. However, the agglomeration of nanoscale catalysts (such as cluster and single atoms) during continuous discharge/charge cycles leads to decreased electrochemical performance and poor cyclic stability. Herein, the ruthenium (Ru) atomic sites anchored on an O-doped molybdenum disulfide (O-MoS2) catalyst (designated as Ru/O-MoS2) was fabricated using a facile impregnation and calcination method. Strong Ru-O coupling between Ru atoms and the O-MoS2 substrate optimizes the localized electronic structure, resulting in improved electrochemical performance and enhanced resistance to Ostwald ripening. When employed as a cathode catalyst for LOBs, Ru/O-MoS2 catalyst exhibits a high reversible specific capacity (18700.5 (±59.8) mAh g−1), good rate capability, and enhanced long-term stability (115 cycles, 1200 h). This study encourages facile and efficient strategies for the development of effective and stable electrocatalysts for use in LOBs.

The active site of Mδ+ tailed by B (or N)-doped graphyne for nitrogen reduction reaction through DFT study

NN bond activation is one of the technical problems in the conversion of N2-to-NH3. In this work, we researched Cr, Mn, Co, Ni, Cu and Pt metal single atoms anchored on B/N-doped graphyne (M/X-GY) catalysts systematically by means of DFT. The results of Bader charge and charge density verified the charge transfers between single metal and the doped graphyne in M/X-GY catalysts. Cr (+1.001 e) and Mn (+0.800 e) exhibit higher positive valence, which is favorable for N2 adsorption. Based on the "donation and back-donation" mechanism, the energies gaps of 5σ-N2 and d-M for M=Cr, Mn and Co have the lower values of 3.01, 3.18, 3.18 eV, respectively, and the N2 adsorption energies on Cr/GY (−2.046 eV) and Mn/GY (−1.622 eV) have the more negative values. As a result, the catalyst of Cr metal atom anchored on GY is promising candidate. The substitution of B can effectively promote the activation of N2 and suppress the hydrogen evolution, while the substitution of N has the minimum ΔG*N-NH of 0.26 eV and ΔGNH3 of 0.08 eV. Compared with two different NRR pathways, the distal mechanism process is more preferential than the alternating pathway. The catalyst of Cr/N-GY has higher stability and can effectively activate N2 to generate *N2H, which can serves as promising catalysts throughout the NRR process.

Theoretical study of the efficiencies of graphyne supported Mo single-atom catalyst (SAC) and Mo-Ni dual-atom catalyst (DAC) on hydrogen evolution reaction

In this work, by adding one molybdenum atom or two molybdenum and nickel atoms on the surface graphyne support, single atom catalyst (SAC) and dual atoms catalyst (DAC) were designed. The different spin multiplicities for both catalysts were analyzed by the relative energies, adsorption energies and frontier orbitals. The results showed in both case of SACs and DACs, the catalyst with spin multiplicity = 3 is desired. Then, the efficiency of these two catalysts as high-performance and cost-effective catalysts in the HER process was investigated theoretically. All calculations were performed using M06-2X/def2SV level of theory. In the HER mechanism, it has been found that the DAC has higher favorability than the SAC. Both steps (Volmer reaction and Tafel or Heyrovsky reaction) are more exothermic using DAC, and the difference between SAC and DAC is higher in the second step. The effect of solvent on these steps has been studied using water and methanol as two common solvents. The reactions are less exothermic in the solvent; but they are still highly exothermic and thermodynamically favorable. Moreover, despite the gas phase data, in both solvents, the use of DAC gives less favorable data versus the SAC. The data also showed the little preference of water versus the methanol as solvent.

Atomic-scale strain engineering of atomically resolved Pt clusters transcending natural enzymes

Strain engineering plays an important role in tuning electronic structure and improving catalytic capability of biocatalyst, but it is still challenging to modify the atomic-scale strain for specific enzyme-like reactions. Here, we systematically design Pt single atom (Pt1), several Pt atoms (Ptn) and atomically-resolved Pt clusters (Ptc) on PdAu biocatalysts to investigate the correlation between atomic strain and enzyme-like catalytic activity by experimental technology and in-depth Density Functional Theory calculations. It is found that Ptc on PdAu (Ptc-PA) with reasonable atomic strain upshifts the d-band center and exposes high potential surface, indicating the sufficient active sites to achieve superior biocatalytic performances. Besides, the Pd shell and Au core serve as storage layers providing abundant energetic charge carriers. The Ptc-PA exhibits a prominent peroxidase (POD)-like activity with the catalytic efficiency (Kcat/Km) of 1.50 × 109 mM−1 min−1, about four orders of magnitude higher than natural horseradish peroxidase (HRP), while catalase (CAT)-like and superoxide dismutase (SOD)-like activities of Ptc-PA are also comparable to those of natural enzymes. Biological experiments demonstrate that the detection limit of the Ptc-PA-based catalytic detection system exceeds that of visual inspection by 132-fold in clinical cancer diagnosis. Besides, Ptc-PA can reduce multi-organ acute inflammatory damage and mitigate oxidative stress disorder.