Atomic Level Research Articles

Molecular dynamics studies reveal the structural impacts of LRRK2 R1441C and LRRK2 D1994A mutations in Parkinson's disease

Parkinson's Disease (PD) is a continuingly deteriorating neurological ailment affecting over 8.5 million patients globally as of 2019, and the numbers are expected to keep rising. To aid in identifying therapeutic targets, molecular dynamics simulations are convenient and cost-effective methods for enriching our knowledge of the molecular pathophysiology of diseases. Many proteins and their corresponding mutations have been identified to contribute to this disease, of which Leucine-rich repeat kinase 2 (LRRK2) is accountable for a significant percentage. Several mutations involving the domains in LRRK2 have been studied, which are known to interfere with various enzymatic processes, ultimately leading to trademark features of PD like aggregation of protein inclusions called Lewy Bodies (LBs), mitochondrial dysfunctions, etc. The precise molecular mechanism of the mutations' pathophysiology is still unclear. This research article looks at the structural effects of mutations, namely the R1441C and D1994A mutations, on the surrounding residues in the protein, offering novel insights into pathophysiological changes at an atomistic level. Our results indicate a gain of electrostatic interactions with a stable αβ motif within the LRR-Roc linker, amongst other changes. This article also highlights the potential involvement and importance of the αβ motif in LRRK2 associated PD.

Transmission electron microscopic study on rutile-type GeO2 film on TiO2 (001) substrate

Rutile-type GeO2 (r-GeO2) with an ultrawide bandgap of ∼4.7 eV has emerged as a promising material for next-generation power-electronic and optoelectronic devices. We performed transmission electron microscopy (TEM) observation to analyze the structural properties of r-GeO2 film on r-TiO2 (001) substrate at an atomic level. The r-GeO2 film exhibits a threading dislocation density of 3.6 × 109 cm−2 and there exist edge-, screw-, and mixed-type dislocations in the film as demonstrated by two-beam TEM. The edge-type dislocations have Burgers vectors of [100] and/or [110]. The bandgap of the r-GeO2 film is 4.74 ± 0.01 eV as determined by electron energy loss spectroscopy.

The alpha particle charge radius, the radion and the proton radius puzzle

AbstractRecent measurements of the Lamb shift of muonic helium-4 ions were used to infer the alpha particle charge radius. The value found is compatible with the radius extracted from the analysis of the electron-helium scattering. Thus, the new spectroscopic data put additional empirical bounds on some free parameters of certain physics theories beyond the Standard Model. In this paper, we analyze the new data in the context of large extra-dimensional theories. Specifically, we calculate the influence of the radion, the scalar degree of freedom of the higher-dimensional gravity, on the energy difference between the 2S and 2P levels of this exotic atom. The radion field is related to fluctuations of the volume of the supplementary space. It should be treated as a phenomenologically independent quantity in relation to the tensorial degrees of freedom of the metric within the braneworld scenario. Based on the spectroscopic data of muonic helium, we find constraints for the effective energy scale of the radion as a function of the alpha particle radius. Then, we discuss the implications of these new constraints on the proton radius puzzle. We also establish a new empirical bound for the radion by examining its influence on the isotopic shift in the 2P-2S transition of muonic hydrogen and muonic deuteron. In connection with this discussion, we study the impact of the radion on the tension observed in measurements of the difference between the squared radii of the helion and alpha particle as extracted from muonic and electronic helium isotopes.

Enhanced Platinum-Based Thin-Film Catalysts for Electro-Oxidation of Methanol

Surface morphology is one of the critical factors affecting the performance of electrocatalysts. Thus, with careful manipulation of the surface structures at the atomic level, the effectiveness of the catalyst can be significantly improved. Heat treatment is an effective method for inducing surface atom rearrangement, hence modifying the catalyst’s characteristics. This study investigated the substrate’s influence and the effect of thermal annealing on the morphology and surface reconstruction of platinum (Pt) thin-film catalysts. Our findings indicate that heat treatment in a reductive atmosphere (95% Ar + 5% H2) at 300 °C can significantly impact the degree of rearrangement of surface atoms. This process induces long-range ordering, resulting in domains with a high proportion of (111) and (100) sites without an epitaxial template. Considering that the reactivity of low-index platinum single crystals for the methanol oxidation reaction follows the following sequence Pt(111) < Pt(110) < Pt(100), increasing the proportion of (100) planes leads to a notable enhancement (up to three times) in performance, compared to untreated catalysts. Furthermore, considering the amount of precious metal consumed, a mass-specific current density obtained on annealed Pt@Ni is larger by one order of magnitude and ~2 times that obtained on Pt@Cr and Pt@GCox catalysts, respectively. Our results demonstrate that an easy-to-implement way of controlling atomic orientations improves catalyst performance. With this contribution, we propose a method for designing improved electrocatalysts, as catalytic reactions occur only at the surface.

Molecular dynamics study of the microstamping of TiAl6V4 alloy.

Microstamping has been shown to enhance the surface strength of alloy materials by improving interatomic density. This paper delves into the damage mechanism of TiAl6V4(TC4), which has been processed using high-speed stamping with varying overlap ratios at the atomic level. Additionally, the general trend of stress variation between loading and unloading is discussed. The mechanical properties of the substrate and the changes in microstructure resulting from varying overlap rates in microstamping were investigated. The impact of different machining overlap ratios on the depth of the damaged layer, the number of dislocation density lines, and the density of the matrix is also explored. The results indicate that the dislocation density remains relatively unchanged due to material hardening, while the overlap ratio increases continuously. Based on this analysis, a more optimal microstamping overlay ratio parameter is proposed to effectively enhance the surface strength of the substrate and reduce processing time. First, an alloy model with titanium, aluminum, and vanadium was created in ATOMSK and LAMMPS software. The model was divided into three layers: fixed, constant temperature, and Newton. To ensure the accuracy of the simulation, the system was annealed in order to minimize energy and replicate real-world conditions. Zhou's EAM alloy potential was employed to represent the interaction between the alloy atoms, while the Tersoff potential was used to represent the interatomic interaction of the diamond indenter. Additionally, the LJ potential function was selected to depict the interaction between the metal atom and the diamond indenter. The construct surface mesh method in OVITO software was then utilized to construct a surface mesh and analyze the impact of different machining overlap rates on surface topography. The common neighborhood analysis (CNA) module in OVITO was used to calculate the number of defective atoms and the depth of the damaged layer. Finally, the DXA (dislocation extraction analysis) module in OVITO was used to calculate the dislocation density length and dislocation density.

Machine learning interatomic potential with DFT accuracy for general grain boundaries in α-Fe

AbstractTo advance the development of high-strength polycrystalline metallic materials towards achieving carbon neutrality, it is essential to design materials in which the atomic level control of general grain boundaries (GGBs), which govern the material properties, is achieved. However, owing to the complex and diverse structures of GGBs, there have been no reports on interatomic potentials capable of reproducing them. This accuracy is essential for conducting molecular dynamics analyses to derive material design guidelines. In this study, we constructed a machine learning interatomic potential (MLIP) with density functional theory (DFT) accuracy to model the energy, atomic structure, and dynamics of arbitrary grain boundaries (GBs), including GGBs, in α-Fe. Specifically, we employed a training dataset comprising diverse atomic structures generated based on crystal space groups. The GGB accuracy was evaluated by directly comparing with DFT calculations performed on cells cut near GBs from nano-polycrystals, and extrapolation grades of the local atomic environment based on active learning methods for the entire nano-polycrystal. Furthermore, we analyzed the GB energy and atomic structure in α-Fe polycrystals through large-scale molecular dynamics analysis using the constructed MLIP. The average GB energy of α-Fe polycrystals calculated by the constructed MLIP is 1.57 J/m2, exhibiting good agreement with experimental predictions. Our findings demonstrate the methodology for constructing an MLIP capable of representing GGBs with high accuracy, thereby paving the way for materials design based on computational materials science for polycrystalline materials.

Atomic‐Scale Order and Disorder Induced Diverse Topological Spin Textures in Self‐Intercalated Van der Waals Magnets Cr1+δTe2

AbstractThe intercalation of magnetic atoms into van der Waals (vdW) gaps offers a versatile approach for manipulating local magnetic ordering in vdW magnets. However, these intercalated magnetic atoms are often intricately positioned within the gaps, resulting in an ambiguous impact on local magnetic interactions and spin configurations. Herein, the atomic and magnetic structures of self‐intercalated prototype materials Cr1+δTe2 are comprehensively investigated using transmission electron microscopy, elucidating the correlation between the concentration and distribution of intercalated Cr atoms and the evolution of spin textures. The observed transitions from topological Néel‐type skyrmions to non‐topological type‐II bubbles, and ultimately to trivial ferromagnetic domains, underscore the complex nature of these magnetic spin textures. The complexity of the local structural arrangements is further revealed through integrating atomic‐resolution imaging, revealing the disorder‐order‐disorder transitions manifested by the distribution of intercalated atoms. The modulation of intercalated atomic structure shapes the observed spin textures by affecting the Dzyaloshinskii−Moriya interaction (DMI), inter/intra‐layer coupling, and magnetic anisotropy. These findings provide profound insights into the structure‐magnetism relationship, offering promising avenues for engineering the magnetic properties of vdW magnets at the atomic level.

Ultra-rapid Synthesis of High-entropy MAX Phases and Their Derivative MXenes for Battery Electrodes.

High-entropy materials hold immense promise for energy storage, owing to their varied compositions and unforeseen physicochemical properties, yet, which poses challenges in synthesis due to tendentious phase separation and extended sintering durations. Herein, an ultra-rapid strategy based on spark plasma sintering (SPS) techniques is proposed to synthesize high-entropy MAX phases within 15 minutes, including a new phase of (Ti0.2V0.2Cr0.2Nb0.2Mo0.2)4AlC3 and several phases of 413-type TiVNbMoAlC3, TiVCrMoAlC3 and (Ti0.2V0.2Cr0.2Nb0.2Ta0.2)4AlC3, achieving utmost purity level up to 99.54%. Under high temperature, the overfeed of Al with low melt point (~660°C) can foster a liquid environment, which remits the immiscibility among starting materials and benefits to diffusion dynamics to some extents. Theoretical calculations are employed to elucidate the thermodynamic preponderance of high-entropy MAX phases in the intricate multi-element systems. Meanwhile, the varied stacking modes among MX slabs in high-entropy MAX phases and the distinct topological transformations to their derivative MXenes can be observed directly at the atomic level. Moreover, four high-entropy MXenes as electrode materials were investigated for rechargeable batteries. Among them, TiVNbMoC3 electrode demonstrates superior lithium-ion storage capabilities with 725 mAh g-1 after 1000 cycles at 1 A g-1, triggering the edification to the application of high-entropy MXenes for energy domain.

Ultra‐rapid Synthesis of High‐entropy MAX Phases and Their Derivative MXenes for Battery Electrodes

High‐entropy materials hold immense promise for energy storage, owing to their varied compositions and unforeseen physicochemical properties, yet, which poses challenges in synthesis due to tendentious phase separation and extended sintering durations. Herein, an ultra‐rapid strategy based on spark plasma sintering (SPS) techniques is proposed to synthesize high‐entropy MAX phases within 15 minutes, including a new phase of (Ti0.2V0.2Cr0.2Nb0.2Mo0.2)4AlC3 and several phases of 413‐type TiVNbMoAlC3, TiVCrMoAlC3 and (Ti0.2V0.2Cr0.2Nb0.2Ta0.2)4AlC3, achieving utmost purity level up to 99.54%. Under high temperature, the overfeed of Al with low melt point (~660°C) can foster a liquid environment, which remits the immiscibility among starting materials and benefits to diffusion dynamics to some extents. Theoretical calculations are employed to elucidate the thermodynamic preponderance of high‐entropy MAX phases in the intricate multi‐element systems. Meanwhile, the varied stacking modes among MX slabs in high‐entropy MAX phases and the distinct topological transformations to their derivative MXenes can be observed directly at the atomic level. Moreover, four high‐entropy MXenes as electrode materials were investigated for rechargeable batteries. Among them, TiVNbMoC3 electrode demonstrates superior lithium‐ion storage capabilities with 725 mAh g−1 after 1000 cycles at 1 A g‐1, triggering the edification to the application of high‐entropy MXenes for energy domain.

Solid-State NMR Analysis of the Dynamics of Cofactors: Comparison of Heliobacterial and Purple Bacterial Reaction Centers.

Photosynthetic reaction centers (RCs) serve as natural engines converting solar energy to chemical energy. Understanding the principles of efficient charge separation and light-induced electron transfer (ET) between the chlorophyll-type pigments might guide the synthesis for artificial photosynthetic systems. We present detailed insight into the dynamics at the atomic level using solid-state NMR techniques applied to the RCs of Heliobacillus (Hb.) mobilis (HbRCs) and the purple bacterium Rhodobacter (R.) sphaeroides (PbRCs). It is assumed that heliobacteria were among the first phototrophic organisms; therefore, their RC can be regarded as ancient. They are constructed homodimerically with perfect C2 symmetry, enabling ET over both branches of cofactors. Modern RCs of R. sphaeroides wild-type (WT) have higher redox power and are functionally highly asymmetric. The dynamics of the cofactors in both RCs has been explored using nuclear hyperpolarization, induced by the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect. Based on the individual incorporation of 13C positions of the cofactors (through supplementation by 13C-δ-aminolevulinic acid), photo-CIDNP magic-angle spinning (MAS) NMR experiments provide access to the local dynamics of the cofactors along the ET path over a broad range of time scales. Theoretical analysis of the dynamic deformation of these macrocycles is also discussed in terms of function. The dynamics observed in HbRCs appears to be correlated to ET. The cofactors in PbRC are significantly less dynamic than those in the HbRC. Relevance for efficiency and redox properties are discussed.

Prodigiosin Demonstrates Promising Antiviral Activity Against Dengue Virus and Zika Virus in In‐silico Study

ABSTRACTDengue (DENV) and Zika virus (ZIKV), transmitted by Aedes mosquitoes, pose significant public health challenges. Effective treatments for these viruses remain elusive, highlighting the urgent need for new efficient antiviral therapies. This study explores prodigiosin, a microbial tripyrrole pigment, as an antiviral agent against both DENV and ZIKV employing advanced analytical approaches which integrate molecular docking, CASTp 3.0 validation and molecular dynamics (MD) simulations providing insights into molecular interactions at an atomic level. Prodigiosin exhibited favourable drug‐likeness properties, meeting Lipinski's rule of five and demonstrating optimal physicochemical and pharmacokinetic characteristics according to Ghose's, Veber's, Egan's and Muegge's filters, essential for oral bioavailability. Absorption, Distribution, Metabolism, Excretion, and Toxicity profiling indicated high intestinal absorption, minimal risk for drug‐drug interactions and a low toxicity profile, with no AMES toxicity, hepatotoxicity, or skin sensitization. Molecular docking revealed prodigiosin's strong binding affinities to NS5 methyltransferases of both DENV (−7.6 kcal/mol) and ZIKV (−7.7 kcal/mol) viruses, suggesting potential disruption of viral replication. Notably, prodigiosin's binding affinities were comparable to ribavirin‐5'‐triphosphate and chloroquine, known inhibitors of DENV and ZIKV, respectively. MD simulations confirmed stable and specific interactions with prodigiosin with low root‐mean‐square deviation values. Additional analyses, including root‐mean‐square fluctuation, radius of gyration and solvent‐accessible surface area, indicated compact and stable complexes. These multi‐parametric in‐silico analytical strategies provide a novel perspective of prodigiosin as an antiviral agent, demonstrating its drug interactions at the molecular level. These promising results suggest that prodigiosin could serve as a broad‐spectrum antiviral agent against both DENV and ZIKV, warranting further experimental validation for therapeutic development against flaviviral infections.

Crystal Chemistry at Interfaces Between Liquid Al and Polar SiC{0001} Substrates

Silicon carbide (SiC) has been widely added into light metals, e.g., Al, to enhance their mechanical performance and corrosion resistance. SiC particle-reinforced metal matrix composites (SiC-MMCs) exhibit low weight/volume ratios, high strength/hardness, high corrosion resistance, and thermal stability. They have potential applications in aerospace, automobiles, and other specialized equipment. The macro-mechanical properties of Al/SiC composites depend on the local structures and chemical interactions at the Al/SiC interfaces at the atomic level. Moreover, the added SiC particles may act as potential nucleation sites during solidification. We investigate local atomic ordering and chemical interactions at the interfaces between liquid Al (Al(l) in short) and polar SiC substrates using ab initio molecular dynamics (AIMD) methods. The simulations reveal a rich variety of interfacial interactions. Charge transfer occurs from Al(l) to C-terminating atoms (Δq = 0.3e/Al on average), while chemical bonding between interfacial Si and Al(l) atoms is more covalent with a minor charge transfer of Δq = 0.04e/Al. The prenucleation at both interfaces is moderate with three to four recognizable layers. The information obtained here helps increase understanding of the interfacial interactions at Al/SiC at the atomic level and the related macro-mechanical properties, which is helpful in designing novel SiC-MMC materials with desirable properties and optimizing related manufacturing and machining processes.

An Efficient Cathode Catalyst for Rechargeable Zinc-air Batteries based on the Derivatives of MXene@ZIFs.

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial processes at the cathode of zinc-air batteries. Developing highly efficient and durable electrocatalysts at the air cathode is significant for the practical application of rechargeable zinc-air batteries. Herein, N-doped layered MX containing Co2P/Ni2P nanoparticles is synthesized by growing CoNi-ZIF on the surface and interlayers of the two-dimensional material MXene (Ti2C3) followed by phosphating calcination. The growth of CoNi-ZIF on the surface of MXene results in the attenuation of high-temperature structural damage of MXene, which in turn leads to the formation of Co2P/Ni2P@MX with a hierarchical configuration, higher electron conductivity, and abundant active sites. The optimized Co2P/Ni2P@MX achieves a half-wave potential of 0.85 V for the ORR and an overpotential of 345 mV for the OER. In addition, DFT calculations were adopted to investigate the mechanism at the atomic and molecular levels. The liquid zinc-air battery with Co2P/Ni2P@MX as the cathode exhibits a specific capacity of 783.7 mAh g-1 and exceeds 280 h (840 cycles) cycle stability, superior to zinc-air batteries constructed by the cathode of commercial Pt/C+RuO2 and other previous works. Furthermore, a solid-state battery synthesized with Co2P/Ni2P@MX as the cathode exhibits stable cycle performance (154 h/462 cycles).

Insight into the direct carbonation process of Ca2SiO4 based on ReaxFF MD simulation and experiments

Ca2SiO4 is the primary carbonation-reactive mineral in steel slag, and demonstrates significant carbon sequestration potential, yet its microscopic reaction processes remain unclear. This study investigated the carbonation behavior of Ca2SiO4 using ReaxFF MD simulations. The results indicated that as CO2 concentration increased, the capture rate of Ca2SiO4 decreased, and the molecular structure of the resulting CaCO3 varied in oxygen origin. At room temperature, the carbonation rate of Ca₂SiO₄ gradually decreased over time until it reached equilibrium. Increasing the temperature could reactivate the carbonation, but the rate would still decline until it reached equilibrium again. Higher temperatures could accelerate the formation of the intermediate C2O52− and internal CO32− diffusion, thereby boosting the carbonation and increasing CO2 adsorption. This study investigated the carbonation of Ca2SiO4 at the atomic level, aiming to link microscopic molecular processes with macroscopic experimental phenomena, thereby providing a theoretical foundation for enhancing the carbonation efficiency of steel slag.

Engineering of hyperentangled complex quantum networks

Abstract We propose a novel scheme to engineer the atomic hyperentangled cluster and ring graph states invoking cavity-QED technique for applicative relevance to quantum biology and quantum communications utilizing the complex quantum networks. These states are engineered using both external quantized momenta states and energy levels of neutral atoms under off-resonant and resonant Atomic Bragg Diffraction (ABD) technique. The study of dynamical capacity and potential efficiency have certainly enhanced the range of usefulness of these states. In order to assess the operational behavior of such states when subjected to a realistic noise environment has also been simulated, demonstrating long enough sustainability of the proposed states. Moreover, experimental feasibility of the proposed scheme has also been elucidated under the prevailing cavity-QED research scenario.

Uncovering structure-activity relationships in Brønsted acidic deep eutectic solvents for extractive and oxidative desulfurization

Modeling the structure-activity relationships (SARs) of deep eutectic solvents (DESs) is crucial for upgrading their catalytic performance in targeted reactions. Herein, a series of Brønsted acidic DESs are developed for the SARs research at molecular and atomic levels. Experimental and theoretical results suggest that the catalytic activity increases with the decreasing distances between O atom of active sites in DESs and S atom in sulfur compounds, and the R2 between EODS efficiency and the valid distances of O···S is above 0.9. Such geometric configuration can be optimized by altering the composition of DESs, which in turn substantially triggers the reaction acceleration between active intermediates and substrates. The resulting DES (TEAC/2BSA) achieved deep desulfurization for various sulfur compounds based on the optimal valid distances of O···S. This work contributes to a deep understanding of the reaction mechanism and enables the effective screening of task-specific DESs.

Atomistic origin of montmorillonite clay subjected to freeze-thaw hysteresis

The freeze-thaw cycles of frozen soil could significantly affect its thermo-hydro-mechanical-chemical (THMC) properties, causing the frost heaving and thawing settlement. The microscale essence is the water-ice phase transition, but the microscale details are still poorly understood, especially at ultra-low temperatures. Nuclear magnetic resonance (NMR) technology and molecular dynamics (MD) simulation methods were performed to explore the freeze-thaw behaviors of montmorillonite clay under temperature of 210 - 293 K. Then, the water-ice phase transition, freeze-thaw hysteresis, ice nucleation mechanism, and surface effect of clay at an atomistic level were discussed. A classification method of different types of unfrozen water through NMR experiment was proposed, including bulk, capillary, and bound water. Here, it is found that: (1) the freeze-thaw process of frozen soil at the macroscale was essentially the occurrence of ice-water phase transition at the microscale. (2) The freeze-thaw hysteresis was caused by different growth and melting rates of ice crystals, where the ice growth/nucleation on clay surface was more difficult to develop. (3) The surface effect of clay was essential for the ice nucleation and the existence of bound water. For example, little unfrozen water still existed in unfrozen soil even at 213 K. (4) For unsaturated frozen soil, the quasi-liquid water was an essential component of unfrozen water that cannot be ignored. This work could provide an atomistic insight to unravel the atomistic origin of the freeze-thaw mechanism of montmorillonite clay and complement relevant experimental evidence.

Direct observation of Schottky-vacancy clusters and their mechanical response in MoN/TiN superlattice

A deeper understanding of vacancy-induced effects in ceramics may lead to optimized material design and mechanical properties. However, current research primarily focuses on the impact of vacancies on the intrinsic mechanical properties of materials, lacking direct experimental validation of their mechanical response behavior. In this study, we closely investigate the influence of Schottky-vacancy defects introduced during the deposition process on the mechanical behavior of MoN/TiN superlattice. In the as-deposited coating, Schottky vacancies are found to be distributed inside MoN as clusters. By coupling FIB with cross-sectional TEM observation, we further revealed Schottky vacancies evolution under loads at the atomic level and their significant impact on superlattice deformation. These Schottky vacancies promote superlattice intermixing and weaken the interface-strengthening effect. However, they are also beneficial to dislocation nucleation and increase the nitride plastic deformability. These findings provide a new perspective on the impact of point defects on the mechanical properties of ceramic materials.

Geometrical features and chemical adsorptions of (Ag3Sn)n clusters

The Ag-Sn alloys are famous ancient intermetallics, with the Ag3Sn being a crucial component of the phase diagram. Recently, Ag3Sn nanoparticles showcase efficient catalytic CO oxidation capabilities. Here, structural features and stability of (Ag3Sn)n (n = 1–6) clusters are first analyzed in detail. The results reveal that structures of them evolve from cages to close-packed icosahedra, where Ag are distributed on cores and gradually aggregated, whereas Sn occupy edge positions and become dispersed. Moreover, the icosahedral (Ag3Sn)3 has a higher stability than that of its neighbors and can maintain the structural integrity at 700 K. The molecular orbitals reveal that the (Ag3Sn)3 has an electronic open-shell configuration of 1S21P61D102S21F1, which is confirmed by the density of states. Electrostatic potential surfaces show that (Ag3Sn)n have significant electron-deficient σ-hole regions at Ag sites, which can make CO stretching frequencies and bond lengths have red-shifts. Adsorption energies between (Ag3Sn)n and CO display odd–even oscillations, ranging from (0.43–0.68) eV, and the direction of charge flows is from CO → clusters. Our work provides inferences to structure evolutions and adsorptions of the Ag3Sn alloy at the atomic level.

The synergistic effect of Co atomic clusters and single atoms facilitates the fenton-like reaction on A- and R-TiO2

The regulation of single atom (SA) sites is crucial for the promotion of advanced oxidation processes (AOPs). Here A- and R-TiO2 with Co mixed sites (clusters and single atoms, CS) were prepared to degrade sulfamethoxazole (SMX) by activating peroxymonosulfate (PMS). Co CS/A-TiO2+PMS system can completely remove SMX within 14 min under secondary effluent and dark conditions, and its rate constant (0.4926 min-1) was 4.4, 3.2 and 2.5 times higher than that of Co SA/R-TiO2, Co SA/A-TiO2 and Co CS/R-TiO2 systems, respectively. Experiments and calculations verified that the electron configuration of Co SA was optimized by Co clusters, facilitating the adsorption, conversion and desorption of PMS by Co SA, leading to the enhancement of Fenton-like activity. Co CS/A-TiO2 catalytic sponges exhibited exceptional degradation performance in microreactor treatment experiment. This work reveals the synergistic effect between SA and clusters at atomic level and provides an all-purpose strategy (catalytic sponge) for the recovery of non-magnetic catalysts in wastewater treatment.