Developing robust and selective catalytic platforms for micropollutant removal in complex water matrices remains a major challenge in advanced oxidation processes. Here, we report a monolithic PVA-modified polyurethane sponge functionalized with Mn–Fe mixed oxide nanocubes (MnFeO@PPUS) as an earth-abundant catalyst for periodate (PI) activation. Using 2,4,6-trichlorophenol (2,4,6-TCP) as a model pollutant, the MnFeO@PPUS/PI system achieved 100% removal of 2,4,6-TCP within 30 min and exhibited pronounced chemoselectivity toward electron-rich substrates, while showing strong tolerance to common inorganic anions and natural organic matter. Mechanistic analyses indicate that 2,4,6-TCP oxidation proceeds mainly through a non-radical pathway involving 1O2-related oxidation and possible interfacial electron-transfer processes, accompanied by reversible Mn/Fe redox cycling. The interconnected macroporous scaffold and immobilized bimetallic oxide interface facilitate solid–liquid contact, catalyst recovery, and continuous-flow operation. The monolithic catalyst also showed good operational stability, sustaining nearly complete removal efficiency for 144 h in continuous-flow operation, while exhibiting limited metal leaching under the tested conditions. These results demonstrate a durable and selective monolithic platform for non-radical periodate activation and practical micropollutant removal.

Electro-Fenton (EF) oxidation efficiency has been constrained by the difficulty of balancing in-situ H2O2 generation with subsequent catalytic activation on a structurally ill-defined interface. In this work, we designed dual-atom catalysts (DACs) to decouple these two steps through adjacent, functionally differentiated active centres operating synergistically. A precisely engineered Co-Cu-N2O4 coordination was obtained via a polymerisation-pyrolysis directed molecular-transformation route. During EF catalysis, the Co-Cu-N2O4 motif drives bidirectional electronic redistribution between the Co and Cu sites, enabling an efficient oxygen-reduction cascade. Specifically, the Co site selectively mediates H2O2 electrosynthesis via two-electron reduction, which is subsequently activated at the adjacent Cu site through OOH⁎ dissociation to form high-valent Cu(III)-OH species and hydroxyl radicals (•OH). Operando ATR-FTIR captures a previously unresolved potential-gated redistribution of OOH⁎ adsorption: at 0.20V, OOH⁎ preferentially adopts a Cu-associated adsorption configuration favourable for Cu(III)-OH and •OH formation, whereas more negative potentials favour a Co-associated OOH⁎ configuration, triggering the unproductive H2O-formation pathway. When integrated into an electrified flow-through membrane reactor, the system achieves >90% single-pass removal of sulfamethoxazole (SMX) and maintains stable operation for over 100h. This work provides design principles for dual-atom interfaces and reveals the molecular-level cooperation that enables efficient cascade environmental electrocatalysis.

Activation upcycling of plastic waste into high-value carbon materials for aquatic pollutant removal presents a promising avenue for addressing environmental challenges. Herein, a Fe-Ni alloy encapsulated in hierarchically ordered macro/meso-microporous carbon (FeNi@HOMC) was synthesized via activator-assisted pyrolysis of waste polystyrene and then employed for periodate (PI) activation. The Fe-Ni heterostructure not only facilitated the formation of porous carbon but also promoted PI activation, generating reactive oxygen species. Meanwhile, the carbon shell prevented metal core aggregation and enhanced electron mobility. FeNi@HOMC exhibited outstanding removal of diverse organic contaminants over a broad pH range (4.0-11.0), demonstrating strong resistance to the effects of anions and humic acids while maintaining long-term stability. Continuous-flow experiments and toxicity assessments confirmed complete pollutant mineralization and reduced biotoxicity within 120 h. Mechanistic investigations revealed a non-radical oxidation pathway driven by high-valent metal species and singlet oxygen (1O2), coupled with an electron-transfer mechanism. The exceptional catalytic performance of FeNi@HOMC-700 was attributed to its abundant Fe/Ni-Nx catalytic centers, nitrogen doping, high surface area, and superior conductivity. This work not only suggests a cost-effective and waste-derived solution for organic pollutant degradation but also provides insights into mitigating plastic-induced environmental hazards.

Ultrathin g-C3N4 nanosheets are regarded as a promising organic photocatalyst for purifying refractory organic pollutants in water bodies. However, due to their high exciton binding energy (Eb), there are still significant challenges in optimizing the dual oxidation pathways mediated by excitons/free carriers to further enhance their oxidation efficiency. Herein, a novel g-C3N4-based photocatalyst was developed, which utilizes dual nitrogen defects (Nv,-C equivalent to N) as anchor points and K+ ions as the medium to construct cross-layer carrier transport channels in ultrathin g-C3N4 nanosheets (denoted as K-2D g-C3N4-xNSs). Experimental results and theoretical calculations demonstrate that K+ can form a stable K-CN3 coordination with dual N defects, which establishes interlayer channels between adjacent nanosheets and introduces donor impurity levels to narrow the bandgap, significantly promoting the binding exciton dissociation and free carrier migration. Notably, the reduction in Eb and enhanced O2 adsorption ability facilitate both the photogenerated hole (hvb+) oxidation pathway mediated by free carrier charge transfer and the 1O2 oxidation pathway mediated by triplet (T1) exciton energy transfer. This leads to the generation of abundant oxidative active species, including hvb+, 1O2, and center dot OH, with hvb+ being predominant. The rate constant for sulfamethoxazole (SMX) degradation by K-2D g-C3N4-xNSs surpasses that of bulk g-C3N4 and pristine ultrathin 2D g-C3N4 nanosheets by 28.6 and 1.89 times, respectively, and it exhibits strong application stability and resistance to interference in complex environmental water matrices. This study advances the development and application of bi-excitons/free carriers in ultrathin g-C3N4-based nanosheets for environmental remediation.

Generation and identification of reactive oxygen species (ROS) in peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) hold great significance for understanding reaction mechanism and controllable synthesis of catalytic materials. Chemical quenching and probe experiments, electron paramagnetic resonance (EPR), and other advanced detection techniques have been widely used to identify the oxidation mechanisms in PMS-AOPs, although some recent reports have indicated the inherent limitations of these strategies. In this review, we systematically summarize the typical characteristics, generation pathways and corresponding oxidation mechanisms of various radical and non-radical processes. A comprehensive inventory of commonly used scavengers, chemical probes, and relevant experimental design methodologies is compiled to facilitate thorough discussions on the identification methods of distinct reaction mechanisms. By dissecting the quenching effect of scavengers on target ROS in reaction systems, we emphasize the validity of these methods and corresponding quenchers in assessing the contributions of ROS to pollutant degradation. Subsequently, a more rational and comprehensive protocol for ROS verification is proposed. In addition, recent advancements in mechanism switching from radical to non-radical oxidation in PMS-AOPs are discussed. Accordingly, we expound the intrinsic conversion mechanism by exploring relationships among catalyst properties, active species generation, and pollutant types. Finally, major challenges and future perspectives of catalyst design and mechanism modulation are suggested. This review offers valuable references for ROS identification in future research, providing new impetus to enhance catalyst performance and regulate reaction mechanisms in PMS-AOP systems.

Hafnium dioxide (HfO2) nanoparticles are high-Z radiosensitizers with established potential for enhancing radiation-induced physical and chemical effects, yet the size-, energy-, and localization-dependent mechanisms underlying HfO2-mediated radiosensitization remain incompletely quantified. In this study, TOPAS Monte Carlo simulations were integrated with TOPAS-nBio radiochemical modeling to investigate the physical dose enhancement and radiolytic species generation associated with HfO2 nanoparticles. Single-particle size-comparison simulations were performed for HfO2 nanoparticles with diameters ranging from 2.5 to 500 nm, whereas subsequent cellular radiochemical simulations focused on nanoparticles of 5 nm radius. The simulations revealed strong dependences of the dose enhancement factor (DEF) and radiochemical yields on photon energy, nanoparticle size, and subcellular localization. Low-energy irradiation produced substantially greater short-range radial dose enhancement adjacent to the nanoparticle surface than MeV-scale irradiation, and nuclear placement yielded the largest whole-cell-averaged DEF values within the idealized 50 nm nanoparticle cell model. In the single-particle radiochemical analysis, ultrasmall HfO2 nanoparticles exhibited higher mass-normalized and surface-area-normalized radiochemical metrics than larger particles, suggesting that the observed size-dependent normalized radiochemical trend cannot be explained solely by increased surface area. In a whole-cell model containing 1000 HfO2 nanoparticles of 5 nm radius, the hydroxyl-radical G-value ratio reached approximately 1.6 at 100 keV. Based on these simulation trends, ultrasmall HfO2 nanoparticles were synthesized and characterized, and simplified in vitro experiments in 4T1 cells under 160 kVp X-ray irradiation showed enhanced ·OH-related fluorescence and a concentration-dependent reduction in cell viability. Overall, this study provides a comparative Monte Carlo framework linking HfO2 nanoparticle size, radiation energy, subcellular distribution, dose deposition, and radiochemical response. The findings support the potential relevance of ultrasmall HfO2 nanoparticles for localized low-energy irradiation settings, while also indicating the need for further experimentally constrained modeling and organelle-specific validation.

Direct catalytic upcycling of solid plastic waste is challenging owing to its chemical robustness, and existing conversion routes often require harsh conditions or costly catalysts. Here, we develop a circular plastic-to-catalyst-to-product strategy converting waste poly(ethylene terephthalate) (PET) bottles into a microwave-responsive composite catalyst for microwave-assisted catalytic plastic upcycling. First, microwave-assisted PET depolymerization and Ni-MOF nanorod crystallization generate abundant missing-cluster defects, inherited during pyrolysis as lattice-distorted Ni nano-cores and edge dislocations encapsulated within a defective carbon shell (Ni@C). These strain-rich Ni─C heterointerfaces enhance dielectric loss and interfacial polarization under microwave irradiation, promoting local microwave energy dissipation at catalyst-plastic contacts and accelerating peroxymonosulfate (PMS) activation. Coupled microwave-thermal-chemical PMS activation initiates polymer-chain disordering, hydrogen abstraction, and C─C bond scission in high-density polyethylene (HDPE) particles before oxidative functionalization, making it more efficient than oxidation-dominated hydrothermal heating. Spectroscopic and strain-mapping analyses reveal that dislocation-rich Ni cores and carbon defects govern microwave energy dissipation and thus catalytic oxidation reactivity. The optimized Ni@C catalyst achieves up to 96% degradation of HDPE and converts products into valuable liquid hydrocarbons and oxygenates with limited phytotoxicity. Overall, this work integrates waste-derived catalyst design with microwave-assisted plastic conversion, offering a route toward circular plastic upcycling and carbon recovery.

A novel catalyst was developed for efficient photoelectrocatalytic of CO2 to CH3OH. Through design and operation, Cu nanoparticles (Cu NPs) were successfully filled into ZrO2 nanotubes (ZrO2 NTs) by the pulse deposition method, and a Schottky junction was formed at the interface between Cu NPs and ZrO2 NTs. The Schottky junction made the free energy barrier of CO2 adsorption on Cu and ZrO2 decrease to 0.44 eV and 0.24 eV, respectively, resulting in more favorable CO2 adsorption. Thus, ZrO2 acted as CO2 main adsorption active site. Meanwhile, the Schottky junction not only decreased the activation energy of CO2(g) to ∗CO2, but also made more electron cloud migrate to the ZrO2 side, resulting in a positive charge on Cu and the transfer of the negatively charged intermediates from ZrO2 to Cu. The reaction free energy barrier in the rate-determining step (from ∗HCOO to ∗HCOOH) on Cu (1.18 eV) was much lower than that on ZrO2 (1.45 eV), which is favorable for the catalytic reaction occurring on Cu. Thus, Cu acts as the main catalytic active site for CO2 reduction to produce CH3OH. Furthermore, the in-situ Fourier Transform Infrared Spectroscopy (FT-IR) and density functional theory calculation confirmed the presence of the intermediates (∗CO2, ∗HCOO, and ∗CH3O). This catalyst design concept provides an important reference for the development of CO2 catalytic materials.

Photothermal catalytic methane reforming (PTCMR) demonstrates a transformative strategy for harnessing full-spectrum sunlight to produce clean solar fuels. Despite extensive efforts related to catalyst development, the pathways and mechanistic complexities arising from photothermal coupling remain underexplored. As such, this Review elucidates the interplay between photochemical and photothermal processes that govern PTCMR, illustrating how photogenerated carriers and localized heating cooperatively or competitively influence reactant adsorption, activation, transformation and active-site evolution. Particular attention is devoted to highlighting the gradient fields (such as, temperature, potential and concentration) within the reactor microenvironment inherent to PTCMR, which exert kinetic control while complicating the quantitative differentiation of intertwined photochemical and photothermal contributions. We examine these challenges and propose novel strategies, integrating catalyst design, reactor engineering and system-coupling to regulate charge-heat interactions and mitigate non-uniform energy effects. Finally, we outline future directions for mechanistic studies and the scalable implementation of next-generation solar-driven methane valorization technologies.

ABSTRACT Covalent organic frameworks (COFs) have been recognized as versatile platforms for photocatalytic CO 2 reduction reactions (CO 2 PRR), owing to their inherent merits of tunable photo‐responsiveness, structural flexibility, high porosity and molecular precision. However, the adsorption and activation of CO 2 within pristine COFs remain challenging due to the lack of strong binding and catalytic sites. To address this, extensive efforts have been dedicated to incorporating active metal centers into COFs, to enhance charge separation, CO 2 adsorption, and redox processes. Despite these advances, a comprehensive analysis correlating metal incorporated strategies with photocatalytic performance remains lacking. This review timely fills this gap by linking the structural and functional properties of metal‐embedded COF with CO 2 PRR activities. We first outline the structural features and design principles of COFs, then highlight representative metal incorporation approaches and the resulting structure–function relationships. Finally, perspectives are presented on the opportunities and challenges of advancing metal‐modified COFs for solar‐driven CO 2 conversion with high performance and on‐demand selectivity. This review will also offer critical insights into intelligent COFs design and inspire future developments in photocatalytic carbon dioxide capture and upgrading.

Monolithic Co-MOF aerogels with Co-O5 sites were developed for PMS activation, overcoming stability and recovery issues. A non-radical pathway via Co(IV)O dominates, formed above 0.65 V. The system achieves 95% SMX removal (pH 4-10) and stable continuous operation for 127 h.

Multimetal oxide with asymmetric atomic sites offers potential solutions for Fenton-like reactions, while their pilot-scale synthesis remains challenging. Herein, we develop a continuous flash Joule heating method using a programmable logic controller with robotic arms to accomplish proof-of-concept of scalable production. The pilot-scale product (178.3 kg h-1 m-2 electrode) of fusion ternary metal oxides was achieved for flow-through water treatment. Integrating multiple reaction electrodes with respective independent power further outlined an increased production path. Experiments and density functional theory calculations proved that fusion CuVFeO structure achieved the dual functionality of organics adsorption on Cu sites and peroxydisulfate activation on Fe sites. The synergistic reaction can be strengthened by V doping endowed with a d band center, leading to an increased Fe Bader charge. Therefore, triple site effects shorten the reaction distance between free radicals (SO4 center dot- and center dot OH) and organics, enhancing free radicals' utilization and production efficiency. CuVFe secures superior performance during long-term operations (1455 min) in a continuous flow-through device. flash Joule heating characterization determined multi transition metals (CuVFe, CoVFe, and MgVFe) can be generally synthesized with a superior catalytic performance. Undoubtedly, continuous flash Joule heating sheds light on developing advanced oxidation materials for pilot-scale wastewater treatment. (c) 2025 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

High-valent iron oxo species (Fe(IV)) are attractive for wastewater treatment because of their high selectivity toward organic pollutants in complex water matrices, but their intrinsic redox properties drive rapid quenching by peroxide precursors, causing excessive chemical consumption. This work addresses this challenge by anchoring Fe(IV) on an iron-phthalocyanine-based conjugated organic framework (FePPC) featuring multi-layered reticular structures and strong π-Fe3d-O2p orbital overlapping. The two-dimensional planar structures provided easily accessible active sites and the extended in-plane conjugation fine-tunes the redox reactivity of surface-confined Fe(IV) species, suppressing unproductive decay while preserving selectivity toward diverse pollutants, yielding a 3.2-fold enhancement in Fe(IV) utilization efficiency. Combined experimental and computational results show that the enhanced orbital overlapping delocalizes electrons at the Fe(IV)═O bond and reduces occupancy of its anti-bonding π* orbital, thereby strengthening the bond against nucleophilic attack by peroxymonosulfate, suppressing O2 evolution, and improving both pollutant selectivity and peroxide stoichiometric efficiency. When integrated into a scale-up membrane reactor, FePPC achieved over 95% micropollutant removal during 72 h of continuous operation. This work fills an important knowledge gap in understanding Fe(IV) redox properties and selectivity, addressing technical bottlenecks in Fe(IV)-based AOP systems toward low-chemical consumption and high-efficiency wastewater treatment.

A wood-N-CoPc catalyst, created by immobilizing cobalt phthalocyanine (CoPc) onto wood, features CoN5 active sites for enhanced peroxymonosulfate activation. Applied in a fixed-bed reactor, this monolithic 3D catalyst demonstrated 85-90% pollutant removal over 128 hours, showcasing its scalability and excellent potential for continuous-flow water treatment.

Photocatalytic methane (CH4) conversion faces a dilemma, where C─H bond activation requires a substantial oxidative driving force, whereas partially oxidized C1 products are intrinsically more susceptible to further oxidation. As a result, strengthening photocatalytic throughput while avoiding overoxidation remains challenging in the field of highly valuable CH4 conversion. Organic semiconductor platforms, including polymeric carbon nitrides (PCN), metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), exhibit structural features that fundamentally differ from those of conventional inorganic counterparts. Their electronic states originate from molecular building units, and their frameworks allow controlled positioning of redox centers, modulation of charge-transfer pathways, and definition of pore environments, enabling systematic regulation of band energetics, carrier distribution, oxygen activation modes, and proton management of photocatalysts. This review examines how electronic structure engineering, interfacial charge routing, reactive species control, and microenvironment design influence pathway selection in CH4 photooxidation. Particular attention is given to mechanisms that favor associative multi-electron oxygen reduction or energy-transfer processes while suppressing hydroxyl radical (•OH)-dominated chemistry. Although CH4-specific systems remain limited, mechanistic insights from related photocatalytic reactions provide transferable design principles. Establishing quantitative relationships between architectural parameters and reactive-species identity is essential for advancing selective solar-driven C1 oxidation.

This study reports a dual-functional monolithic catalyst (Ni-SS@PS-700) prepared by catalytic pyrolysis of waste polystyrene on nickel-deposited stainless-steel mesh for micropollutant degradation via peroxymonosulfate (PMS) activation. The catalyst features in situ-grown carbon nanotubes (CNTs) embedded with FeNi alloy nanoparticles, forming a conductive and redox-active architecture. This structure enables PMS activation through synergistic radical (SO4 center dot- , HO center dot) and non-radical (O-1(2), interfacial electron transfer) pathways, driven by Fe/Ni redox cycling and CNT-mediated charge transport. The catalyst achieved 99.6 % removal and 72.9 % mineralization of sulfamethoxazole within 120 min and maintained over 85% efficiency during 120 h of continuous-flow operation. Mechanistic studies confirmed the coexistence of multiple reactive oxygen species and electron transfer processes. Toxicity assessments of transformation products revealed significantly reduced ecological risks. This work introduces a scalable, sustainable strategy integrating plastic waste valorization with micropollutant removal, offering a robust catalytic platform for advanced oxidation processes and environmentally friendly water treatment applications.

Photocatalytic seawater splitting provides a sustainable route to green hydrogen, but faces barriers of inefficiency and scalability. Graphitic carbon nitride (g-C3N4, CN) offers saline tolerance, yet its catalytic potential requires atomic-level control of structure and charge dynamics. Herein, we design three single-atom Co configurations on CN, including symmetric Co-N4, vacancy-anchored Co-N3, and asymmetric Co-N4. The asymmetric Co-N4 in hierarchically porous carbon nitride (CoSA-hCN) introduces second-shell carbon vacancies that reshape electronic asymmetry and charge dynamics, establishing a robust pathway for effective salinity-mediated charge transfer and in situ Pt photodeposition for H2 evolution. On a scalable 60 cm2 floating photothermal platform under 1 sun, H2 production (47.7 mmol m-2 h-1) and interfacial seawater evaporation (1.88 kg m-2 h-1) are achieved directly from natural seawater. In this work, we offer design principles for a single-atom catalyst on scalable photothermal platform for coupled seawater splitting and desalination.

Ultrafast Joule heating (UJH) has emerged as a cutting-edge technology for synthesizing advanced functional materials (AFMs), representing a burgeoning field of research with significant scientific and industrial implications.

Advanced oxidation processes (AOPs) coupled with microbial fuel cells (MFCs) offer a sustainable route for wastewater treatment and power recovery. Nevertheless, conventional radical-based AOP pretreatment inevitably generates biotoxic byproducts that severely inhibit subsequent MFC microorganisms. Herein, we report a sequential two-stage system: a O-1(2)-dominated non-radical AOP using FeNx/C catalysts with optimized Fe/Fe3C content, followed by MFC treatment. Low-spin Fe-II-N-4 serves as the primary active site for peroxymonosulfate (PMS) activation, while Fe/Fe3C acts as an electronic modulator. An optimal Fe/Fe3C content enhances the Lewis acidity of Fe centers, balancing PMS adsorption and O-1(2) desorption, thereby promoting selective O-1(2) production. When coupled with PMS, the optimal FeNx/C-700 catalyst endows the oxidation system with high activity, stability, robustness, wide pH adaptability, and minimal Fe leaching. Notably, the O-1(2)-dominated AOP effectively converts refractory tetracycline into biodegradable, low-toxicity intermediates (BOD5/COD > 0.3, E. coli inhibition from 96.2% to 30.2%). Feeding this effluent to a downstream MFC yields a cumulative TOC removal of 74.7% over five cycles and a stable power density of 234 mW m(-2), demonstrating carbon-energy synergistic recovery, not merely pollutant mineralization. Overall, this work provides a rational design for biocompatible AOP-MFC sequential systems and elucidates the electronic modulation mechanism of coexisting metal species on single-atom active sites.

Photothermal catalysis has emerged as a powerful strategy to complement photocatalysis by harnessing full-spectrum sunlight for the production of solar fuels and chemical upgrading. Despite its promise, practical implementation remains limited by inefficient management of light-to-electron/heat conversion and unclear catalytic mechanisms. Superlattice materials, featuring periodic structural order across atomic to macroscopic scales, offer tuneable sized crystals, controllable electronic structures, and unique catalytic functionalities. These attributes enable enhanced light capture, energy conversion, and highly efficient catalytic kinetics for photothermal catalysis. This review provides an overview of superlattice architectures in photothermal catalysis, with a systematic review of the mechanism at both atomic and macroscopic scales. Emphasis is placed on the mechanism of superlattice engineering in regulating key photothermal processes, including photo-electron-phonon coupling and multi-energy-carrier dynamics. Advanced microscopic and operando characterization techniques are highlighted to elucidate reaction pathways and disentangle photothermal and photoelectrochemical contributions. Representative photothermal reactions are discussed to demonstrate how superlattice nanostructures enhance reactivity, selectivity, and product upgrading. Finally, challenges and future opportunities are outlined. This work aims to advance photothermal catalysis by introducing ultra-fast, directional photon-electron-phonon transport channels and tailoring highly ordered surfaces and interfaces to steer solar-driven catalysis toward more efficient, selective, and value-oriented chemical transformations.