Efficient Removal of Antibiotic Resistance Genes through 4f-2p-3d Gradient Orbital Coupling Mediated Fenton-Like Redox Processes

Dual-engineered strategy of Ni-CeOv nanozyme with enhanced oxidase activity for sensitive colorimetric detection of total antioxidant capacity

Antioxidants are crucial in the fight against reactive oxygen species and thus in maintaining organismal health, so it is particularly important to realize a rapid and quantitative assay for common antioxidants in life. Current nanozyme-based total antioxidant capacity (TAC) assays face limitations: hydrogen peroxide (H2O2) dependence, noble metal costs, and poor antioxidant discrimination. To address these challenges, we engineered a dual-regulated Ni-doped CeO2 (Ni-CeOv) nanozyme through oxygen vacancy engineering and 3d-2p-4f orbital coupling. Density functional theory (DFT) calculations revealed that Ni doping synergistically affects the spontaneous formation of oxygen vacancies and enhances electron transfer through gradient orbital hybridization, resulting in a 2-fold increase in oxidase-like activity (Vmax = 0.10 μM/s) compared to undoped CeO2. Leveraging this H2O2-independent nanozyme, we developed a portable colorimetric platform capable of both ultra-sensitive detection and antioxidant discrimination through distinct inhibition kinetics. Integration with smartphone-based paper sensors enabled on-site TAC quantification in commercial beverages and cosmetics within 5 min, achieving recovery rates of 98.35-104.41 %, at a cost of only $0.2/assay. This work establishes a paradigm for developing low-cost, field-deployable nanozyme sensors for the detection of TAC.

Synchronization Strategy for Activity and Stability in Fenton-Like Single-Atom Catalysis

Single-atom catalysts (SACs) have garnered significant attention in the applications of environmental remediation based on Fenton-like systems. Current research on Fenton-like single-atom catalysis often emphasizes catalytic activity and mechanism regulation, while paying limited attention to the simultaneous enhancement of both activity and stability-a critical factor for the practical and scale-up applications of SACs. This review systematically summarizes recent advances in synchronization strategies for improving the activity and stability of Fenton-like single-atom catalysis, with a focus on the design principles and mechanisms of four key strategies: coordination engineering, confinement effects, carrier substitution, and catalytic module design. To the best of knowledge, this represents the first comprehensive review of Fenton-like single-atom catalysis from the perspective of concurrent optimization of activity and stability. Additionally, the auxiliary role of machine learning and lifecycle assessment (LCA) is evaluated in advancing these synchronization strategies. By investigating the interplay among different support materials, coordination configurations, and reaction environments, as well as enlarged modules, key factors governing the stability/activity of SACs are highlighted, and future directions are proposed for developing next-generation catalysts with high efficiency and long-term durability for practical environmental remediation.

Iron Single-Atom Based Double-Reaction-Center Catalysis Triggers Internal-Driven and External-Driven Pathways for Green Fenton-Like Chemistry

Double-reaction-centers (DRCs) Fenton-like chemistry with low or zero oxidant addition has garnered increasing attentions due to their alignment with the principles of green and sustainable development. However, the regulation of such processes remains a significant challenge, primarily due to deficiencies in the microscopic interpretation of their electron migration mechanisms operating with low or zero oxidant addition. In this work, iron single-atom DRCs catalyst (Fe/N-SAC) was prepared for internal-driven system (zero oxidant addition) and external-driven system (low peroxymonosulfate [PMS] addition). Results indicated the absence of dissolved oxygen activation in the PMS-zreo Fe/N-SAC system, and the iron single atoms in the Fe/N-SAC acted as the predominate electron acceptors to extract the electrons from the electron-donating pollutants with iron valence decreasing from +2.37 to +2.07 and they could also be recovered under O2 atmosphere. In contrast, the electrons from the pollutants could be transferred to both PMS and iron atoms in the external-driven Fe/N-SAC/PMS system involving both predominant electron transfer process (ETP) and iron internal-driven. Furthermore, two experimental devices based on core mechanisms of internal-driven and external-driven systems were designed to achieve long-term operation. These studies will complement the core catalytic mechanisms and module applications of internal-driven and external-driven DRCs systems.

Intrinsic strain of defect sites steering chlorination reaction for water purification

Carbon nanotube (CNT)-based heterogeneous advanced oxidation processes (AOPs) used for water purification have been exploited for several decades. Many strategies for modifying CNTs have been utilized to improve their catalytic performance in remediation processes. However, the strain fields of the intrinsic defect sites on CNT steering AOPs (such as chlorination) have not yet been reported. Here, we explored the strained defect sites for steering the chlorination process for water purification. The strained defect sites with the elongated sp2 hybridized C-C bonds boost electronic reactivity with the chlorine molecules via the initial Yeager-type adsorption. As a result, the reactive species in chlorination can be regulated on demand, such as the ratio of high-selectivity ClO• ranging from 38.8% in conventional defect-based systems to 87.5% in our strain-dominated process, which results in the generation of harmless intermediates and even deep mineralization during 2,4-DCP abatement. This work highlights the role that strain fields have on controlling the extent of chlorination reactions.

Surface-hydroxylated single-atom catalyst with an isolated Co-O-Zn configuration achieves high selectivity in regulating active species

Single-atom catalysts (SACs) are emerging as potent tools for the selective regulation of active species, offering substantial promise for green and sustainable Fenton catalysis. However, current SACs face limitations due to the specificity of their supports, which only allow selective regulation within certain oxidant systems. This constraint makes targeted regulation across different systems challenging. In response, this study designs a SAC, termed CoSAs-ZnO, featuring surface hydroxylation and an isolated asymmetric Co-O-Zn configuration. This SAC can realize a nearly 100% selective generation of sulfate radicals (SO4•-) and singlet oxygen (1O2) in peroxymonosulfate (PMS) and peracetic acid (PAA) systems, respectively. Moreover, the PMS-activated system can efficiently treat electron-deficient-dominated and refractory benzoic acid wastewater, achieving 100.0% removal in multiple consecutive pilot-scale experiments. The PAA-activated system facilitates the rapid conversion of benzyl alcohol to benzaldehyde, with a high selectivity of 89.0%. Detailed DFT calculations reveal that the surface hydroxyl groups on ZnO play a critical role in modulating the adsorption configurations of the oxidants, thus enabling the selective generation of specific active species in each system. This study provides insights into the design of SACs for multifunctional applications and paves the way for their deployment in wastewater treatment and high-value chemical conversion.

MnxCo3-xO4 spinel activates peroxymonosulfate for highly effective bisphenol A degradation with ultralow catalyst and persulfate usage

Persulfates-based advanced oxidation processes are highly efficient in degrading refractory organic contaminants in wastewater. However, their practical application is often limited by the extensive consumption of catalysts and oxidants. Therefore, constructing catalysts with abundant and efficient reaction interfaces is essential for improving the efficiency of persulfate activation. In this work, we develop a novel MnxCo3-xO4 spinel with highly exposed surface active sites by etching Mn-based precursors with Co ions. This process forms sufficient interface Co-O-Mn bonds, which effectively activate peroxymonosulfate (PMS) for bisphenol A (BPA) degradation. A clear structure-activity relationship is observed between the Co/Mn content ratio and the BPA degradation rate in the MnxCo3-xO4/PMS system. Notably, Mn0.1Co2.9O4 demonstrates superior PMS activation efficiency, achieving 100 % degradation of 10 mg/L BPA within 2 minutes with 0.05 g/L catalyst and 0.05 g/L persulfate usage. Experimental analyses combined with theoretical calculations identify the interface Co-O-Mn as the active site, which plays a crucial role in accelerating PMS molecule adsorption and O-O bond activation. Additionally, the spatially adjacent Co-O-Mn sites promote redox cycling for efficient interface electron transfer during the PMS activation process. Furthermore, Zebrafish toxicity studies revealed a considerable reduction in the toxicity of the BPA treatment residue in the MnxCo3-xO4/PMS system. Overall, this work presents a novel strategy for constructing spatially adjacent redox sites in dual-metal spinel materials, offering valuable insights into reducing chemical input and advancing persulfate-based environmental remediation technology.

Oxidative Polymerization in Water Treatment: Chemical Fundamentals and Future Perspectives

For several decades, the methodology of complete destruction of organic pollutants via oxidation, i.e., mineralization, has been rooted in real water treatment applications. Nevertheless, this industrially accepted protocol is far from sustainable because of the excessive input of chemicals and/or energy as well as the unregulated carbon emission. Recently, there have been emerging studies on the removal of organic pollutants via a completely different pathway, i.e., polymerization, meaning that the target pollutants undergo oxidative polymerization reactions to generate polymeric products. These studies have collectively shown that compared to the conventional mineralization pathway, the polymerization pathway allows more efficient removal of target pollutants, largely reduced input of chemicals, and suppressed carbon emission. In this review, we aim to provide a comprehensive examination of the fundamentals of the oxidative polymerization process, current state-of-the-art strategies for regulation of the polymerization pathway from both kinetic and thermodynamic perspectives, and resource recovery of the formed polymeric products. In the end, the limitations of the polymerization process for pollutant removal are discussed, with perspectives for future studies. Hopefully, this review could not only provide critical insight for the advancement of polymerization-oriented technologies for removal of more organic pollutants in a greener manner but also stimulate more paradigm innovations for low-carbon water treatment.

Mesoporous Atomically Dispersed Fe Catalysts with Enhanced Nonradical Pathways in Fenton-like Reactions: The Role of SiO2 Templates

Single-atom catalysts (SACs) are extensively applied in Fenton-like catalytic processes to treat water pollutants. However, the role of the porous structures of SACs supports in catalytic reactions is often overlooked despite its significant contribution to mass diffusion during the reaction. Herein, we adopted a hard-template-assisted approach to fabricate Fe-based SACs (Fe-SACs) featuring a mesoporous architecture. The SiO2 template not only adjusts the pore architecture of the support but also facilitates the conversion of active sites from nanoscale sites to single-atom sites, thereby improving the selectivity for pollutant degradation via nonradical pathways (singlet oxygen and electron transfer mechanism). The experimental results demonstrated that using large-sized SiO2 (∼200 nm) as a template leads to metal aggregation on its surface, forming Fe nanoparticles (Fe-NPs). Fe-NPs exhibit narrow pore structures that prevent peroxymonosulfate (PMS) from being activated, resulting in a slow degradation of pollutants primarily through radical pathways. In contrast, employing small-sized SiO2 (∼10 nm) as a hard template not only produces supports with mesoporous structures but also promotes the building of single-atom active sites. The prepared Fe-SACs effectively activated PMS through nonradical pathways and removed contaminants at a rate k of 0.89 min-1, 33 times faster than Fe-NPs. This template-assisted method sheds light on the synthesis of effective Fenton-like catalysts with porous structures that enhance the efficient breakdown of contaminants in wastewater.

Oxygen vacancies and Y-O-Ag bonds in the Z-scheme heterojunction cooperate to promote photodegradation of organic pollutants

Y2O3 is a cost-effective and environmentally friendly wide-band gap photocatalyst with extensive application potential. However, its limited ability to be excited by visible light restricts its practical uses. In this study, we coupled the narrow bandgap semiconductor AgI with Y2O3 to form a Z-scheme heterostructure, significantly promoting its photocatalytic degradation activity. Characterization and experimental results demonstrated the formation of Y-O-Ag bonds through coupling with AgI, leading to an increase in oxygen vacancies in Y2O3, which promotes the chemisorption of H2O and O2. The Y-O-Ag bond introduction promotes electron transfer, improves hole utilization, and boosts energy transfer efficiency, thus promoting the efficient generation of ·OH and 1O2. The photocatalytic degradation rates of RhB and o-nitrophenol by 7.5% AgI/Y2O3 were 26.5 and 4 times higher than those of pure Y2O3, respectively. This study provides theoretical support for the Z-scheme heterojunction to improve photocatalytic activity and offers efficient solutions and practical design ideas for sewage purification.

4d-2p-4f Gradient Orbital Coupling Enables Tandem Catalysis for Simultaneous Abatement of N2O and CO on Atomically Dispersed Rh/CeO2 Catalyst

N2O and CO coexist in various industrial and mobile sources. The synergistic reaction of N2O and CO to generate N2 and CO2 has garnered significant research interest, but it remains extremely challenging. Herein, we constructed an atomically dispersed Rh-supported CeO2 catalyst with asymmetric Rh-O-Ce sites through gradient Rh 4d-O 2p-Ce 4f orbital coupling. This design effectively regulates the 4f electron states of Ce and promotes the electron filling of the O 3π* antibonding orbital to facilitate N-O bond cleavage. Near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) reveals that CO reacts with the surface-adsorbed O* generated by N2O decomposition through self-tandem catalysis, accelerating the rate-limiting step in N2O decomposition and activating the synergistic reaction of N2O and CO at temperatures as low as 115 °C. This work can guide the development of high-performance catalysts using the strategy of high-order orbital hybridization combined with the tandem concept to achieve versatile catalytic applications.

Manipulating the Spin State of Spinel Octahedral Sites via a π-π Type Orbital Coupling to Boost Water Oxidation

Spin state is often regarded as the crucial valve to release the reactivity of energy-related catalysts, yet it is also challenging to precisely manipulate, especially for the active center ions occupied at the specific geometric sites. Herein, a π-π type orbital coupling of 3d (Co)-2p (O)-4f (Ce) was employed to regulate the spin state of octahedral cobalt sites (CoOh) in the composite of Co3O4/CeO2. More specifically, the equivalent high-spin ratio of CoOh can reach to 54.7 % via tuning the CeO2 content, thereby triggering the average eg filling (1.094) close to the theoretical optimum value. The corresponding catalyst exhibits a superior water oxidation performance with an overpotential of 251 mV at 10 mA cm-2, rivaling most cobalt-based oxides state-of-the-art. The π-π type coupling corroborated by the matched energy levels between Ce t1u/t2u-O and CoOh t2g-O π type bond in the calculated crystal orbital Hamilton population and partial density of states profiles, stimulates a π-donation between O 2p and π-symmetric Ce 4fyz 2 orbital, consequently facilitating the electrons hopping from t2g to eg orbital of CoOh. This work offers an in-depth insight into understanding the 4f and 3d orbital coupling for spin state optimization in composite oxides.

The mechanism differences between sulfadiazine degradation and antibiotic resistant bacteria inactivation by iron-based graphitic biochar and peroxydisulfate system

In this study, the activation of peroxydisulfate (PS) by K2FeO4-activation biochar (KFeB) and acid-picking K2FeO4-activation biochar (AKFeB) was investigated to reveal the mechanism differences between iron site and graphitic structure in sulfadiazine (SDZ) degradation and ARB inactivation, respectively. KFeB/PS and AKFeB/PS systems had similar degradation property towards SDZ, but only KFeB/PS system showed excellent bactericidal property. The mechanism study demonstrated that dissolved SDZ was degraded through electron transfer pathway mediated by graphitic structure, while suspended ARB was inactivated through free radicals generated by iron-activated PS, accompanied by excellent removal on antibiotic resistance genes (ARGs). The significant decrease in conjugative transfer frequency indicated the reduced horizontal gene transfer risk of ARGs after treatment with KFeB/PS system. Transcriptome data suggested that membrane protein channel disruption and adenosine triphosphate synthesis inhibition were key reasons for conjugative transfer frequency reduction. Continuous flow reactor of KFeB/PS system can efficiently remove antibiotics and ARB, implying the potential application in practical wastewater purification. In conclusion, this study provides novel insights for classified and collaborative control of antibiotics and ARB by carbon-based catalysts driven persulfate advanced oxidation technology.

Deciphering the Role of Microbial Extracellular and Intracellular Organic Matter in Antibiotic Photodissipation: Molecular and Fluorescent Profiling under Natural Radiation

This study addresses existing gaps in understanding the specific involvement of dissolved organic matter (DOM) fractions in antibiotic photolysis, particularly under natural conditions and during DOM photobleaching. Employing fluorescent, chemical, and molecular analysis techniques, it explores the impact of extracellular and intracellular organic matter (EOM and IOM) on the photodissipation of multiclass antibiotics, coupled with DOM photobleaching under natural solar radiation. Key findings underscore the selective photobleaching of DOM fractions, propelled by distinct chemical profiles, influencing DOM-mediated antibiotic photolysis. Notably, lipid-like substances dominate in the IOM, while lignin-like substances prevail in the EOM, each uniquely responding to sunlight and exhibiting selective photobleaching. Sunlight primarily targets fulvic acid-like lignin components in EOM, contrasting the initial changes observed in tryptophan-like lipid substances in IOM. The lower photolability of EOM, attributed to its rich unsaturated compounds, contributes to an enhanced rate of indirect antibiotic photolysis (0.339-1.402 h-1) through reactive intermediates. Conversely, the abundance of aliphatic compounds in IOM, despite it being highly photolabile, exhibits a lower mediation of antibiotic photolysis (0.067-1.111 h-1). The triplet state excited 3DOM* plays a pivotal role in the phototransformation and toxicity decrease of antibiotics, highlighting microbial EOM's essential role as a natural aquatic photosensitizer for water self-purification. These findings enhance our understanding of DOM dynamics in aquatic systems, particularly in mitigating antibiotic risks, and introduce innovative strategies in environmental management and water treatment technologies.

Nanoconfinement steers nonradical pathway transition in single atom fenton-like catalysis for improving oxidant utilization

The introduction of single-atom catalysts (SACs) into Fenton-like oxidation promises ultrafast water pollutant elimination, but the limited access to pollutants and oxidant by surface catalytic sites and the intensive oxidant consumption still severely restrict the decontamination performance. While nanoconfinement of SACs allows drastically enhanced decontamination reaction kinetics, the detailed regulatory mechanisms remain elusive. Here, we unveil that, apart from local enrichment of reactants, the catalytic pathway shift is also an important cause for the reactivity enhancement of nanoconfined SACs. The surface electronic structure of cobalt site is altered by confining it within the nanopores of mesostructured silica particles, which triggers a fundamental transition from singlet oxygen to electron transfer pathway for 4-chlorophenol oxidation. The changed pathway and accelerated interfacial mass transfer render the nanoconfined system up to 34.7-fold higher pollutant degradation rate and drastically raised peroxymonosulfate utilization efficiency (from 61.8% to 96.6%) relative to the unconfined control. It also demonstrates superior reactivity for the degradation of other electron-rich phenolic compounds, good environment robustness, and high stability for treating real lake water. Our findings deepen the knowledge of nanoconfined catalysis and may inspire innovations in low-carbon water purification technologies and other heterogeneous catalytic applications.

Electronic Metal-Support Interactions Boost *OOH Intermediate Generation in Cu/In2Se3 for Electrochemical H2O2 Production

Two-electron oxygen reduction reaction (2e- ORR) is a promising method for the synthesis of hydrogen peroxide (H2O2). However, high energy barriers for the generation of key *OOH intermediates hinder the process of 2e- ORR. Herein, we prepared a copper-supported indium selenide catalyst (Cu/In2Se3) to enhance the selectivity and yield of 2e- ORR by employing an electronic metal-support interactions (EMSIs) strategy. EMSIs-induced charge rearrangement between metallic Cu and In2Se3 is conducive to *OOH intermediate generation, promoting H2O2 production. Theoretical investigations reveal that the inclusion of Cu significantly lowers the energy barrier of the 2e- ORR intermediate and impedes the 4e- ORR pathway, thus favoring the formation of H2O2. The concentration of H2O2 produced by Cu/In2Se3 is ~2 times than In2Se3, and Cu/In2Se3 shows promising applications in antibiotic degradation. This research presents a valuable approach for the future utilization of EMSIs in 2e- ORR.

Precise Modulation of the Coordination Environment of Single Cu Site Catalysts to Regulate the Peroxymonosulfate Activation Pathway for Water Remediation

Single atom site catalysts (SACs) with atomically dispersed active sites can be expected to be potential ideal catalysts for accurately modulating the persulfate activation pathway during the water remediation process because of their well-defined structure and the maximum metallic atom utilization. In this paper, a series of Cu SACs with different coordination environments were synthesized to elaborately regulate the peroxymonosulfate activation pathway in AOPs to clarify active species generation and transformation in water remediation. The degradation rate constants (kobs) of Cu-N2, Cu-N3, and Cu-N4 were 0.028, 0.021, and 0.015 min-1, respectively. Cu-N2 SACs exhibited a noticeable enhanced performance for bisphenol A (BPA) removal from water compared to that of the Cu-Nx SACs (x = 3, 4), accompanied by peroxymonosulfate (PMS) activation pathway variation. As shown by experimental and theoretical results, the PMS activation pathway was transformed from ROS to electron transfer with nitrogen coordination numbers decreasing from 4 to 2, which can be ascribed to the uneven charge distribution of Cu sites as well as upshifts in the d-band center, and thereby optimized electron transfer for PMS activation. Furthermore, the increasing nitrogen vacancies of single Cu site catalysts can also result in more unoccupied 3d orbitals of Cu atoms in SACs, thereby improving the intermediates' (PMS and BPA) adsorption-desorption process and BPA removal performance. These findings provided a beneficial approach for the coordination number regulation of SACs in water remediation.

Molecular level removal of antibiotic resistant bacteria and genes: A review of interfacial chemical in advanced oxidation processes

As a kind of novel and persistent environmental pollutants, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been frequently detected in different aquatic environment, posing potential risks to public health and ecosystems, resulting in a biosecurity issue that cannot be ignored. Therefore, in order to control the spread of antibiotic resistance in the environment, advanced oxidation technology (such as Fenton-like, photocatalysis, electrocatalysis) has become an effective weapon for inactivating and eliminating ARB and ARGs. However, in the process of advanced oxidation technology, studying and regulating catalytic active sites at the molecular level and studying the adsorption and surface oxidation reactions between catalysts and ARGs can achieve in-depth exploration of the mechanism of ARGs removal. This review systematically reveals the catalytic sites and related mechanisms of catalytic antagonistic genes in different advanced oxidation processes (AOPs) systems. We also summarize the removal mechanism of ARGs and how to reduce the spread of ARGs in the environment through combining a variety of characterization methods. Importantly, the potential of various catalysts for removing ARGs in practical applications has also been recognized, providing a promising approach for the deep purification of wastewater treatment plants.

Unlocking Bimetallic Active Centers via Heterostructure Engineering for Exceptional Phosphate Electrosorption: Internal Electric Field-Induced Electronic Structure Reconstruction

Development of electrode materials exhibiting exceptional phosphate removal performance represents a promising strategy to mitigate eutrophication and meet ever-stricter stringent emission standards. Herein, we precisely designed a novel LaCeOx heterostructure-decorated hierarchical carbon composite (L8C2PC) for high-efficiency phosphate electrosorption. This approach establishes an internal electric field within the LaCeOx heterostructure, where the electrons transfer from Ce atoms to neighboring La atoms through superexchange interactions in La-O-Ce coordination units. The modulatory heterostructure endows a positive shift of the d band of La sites and the increase of electron density at Fermi level, promoting stronger orbital overlap and binding interactions. The introduction of oxygen vacancies during the in situ nucleation process reduces the kinetic barrier for phosphate-ion migration and supplies additional active centers. Moreover, the hierarchical carbon framework ensures electrical double-layer capacitance for phosphate storage and interconnected ion migration channels. Such synergistically multiple active centers grant the L8C2PC electrode with high-efficiency record in phosphate electrosorption. As expected, the L8C2PC electrode demonstrates the highest removal capability among the reported electrode materials with a saturation capacity of 401.31 mg P g-1 and a dynamic capacity of 91.83 mg P g-1 at 1.2 V. This electrochemical system also performs well in the dephosphorization in natural water samples with low concentration that enable effluent concentration to meet the first-class discharge standard for China (0.5 mg P L-1). This study advances efficient dephosphorization techniques to a new level and offers a deep understanding of the internal electric field that regulates metal orbitals and electron densities in heterostructure engineering.