Selective transformation of phenolic pollutants into value-added chemicals has garnered significant attention, yet radical-dominated oxidation pathways generally lead to complete mineralization of organic carbon into CO2. Herein, Fe-N5 single-atom with progressively incorporated atomic clusters and nanoparticles were synthesized, establishing tunable electronic modulation and reactive species regulation. Notably, short-range coupling and tunneling effect between Fe nanoclusters and Fe-N5 sites tuned d-orbital energy, enabling optimal peroxide antibonding orbital occupancy with a function of confined electron-transfer pathway (ETP) evolution. The optimized FeSA/NC system exhibits superior and matrix-tolerant water purification, achieving 75.2% TOC removal and selective C-C phenolic coupling products. Mechanistic investigations and DFT calculations reveal that proton-coupled electron transfer (PCET) at carbon sites promotes formation of thermodynamically stable dimers in FeSA/NC system, whose frontier orbitals (-2.17 eV) energetically mismatch with catalyst-PMS* complexes (-3.39 eV), suppressing further electron exchange and oxidation. Life cycle assessment further confirms the lower ecological footprint and favorable sustainability profile of FeSA/NC system. This study highlights the critical synergism effect of multiscale Fe species in modulating electronic structure and reactive species, providing insight into ETP-driven selective phenolic coupling in advanced oxidation systems.

The increasing presence of microplastics in the aquatic and terrestrial food chains calls for the need to come up with innovative and effective remediation approaches. Such innovations as zinc oxide (ZnO) structures and metal–organic frameworks (MOFs) are examined as the second generation of photocatalysts for degrading microplastics under sunlight. We will focus on the latest advances and discuss the structure of photocatalytic processes, their functioning under various light conditions, and their environmental impacts, especially environmental safety and ecotoxicity. ZnO structures are even better photocatalysts because they form reactive oxygen species (ROS) as good as other metal oxides. However, their possible cytotoxicity and the ability to generate oxidative stress require serious evaluation. MOFs, on the contrary, offer physicochemical properties, environmental safety, ecotoxicity, and environmentally friendly synthesis pathways, making them a worthy substitute. The review underscores the urgency of incorporating environmental safety and ecotoxicity into the design of photocatalysts, thereby unlocking their full potential while avoiding environmental or human health risks. Moving forward in the field of sustainable nanotechnology to remove microplastics will provide the way to come up with green innovations and hence guarantee the effectiveness of combating plastic pollution in long-term stability.

A limited understanding of micro-structure-activity relationship hinders a precise control of the electronic and geometric structure of the active sites for efficient peroxymonosulfate (PMS) activation. In this study, we present a rational synthetic strategy to simultaneously tailor the coordination geometry of single-atom Fe and the molecular structure of the support. The results reveal the critical impact of the molecular configuration of the support on the catalytic behavior of Fe-N3 center. High catalytic activity of Fe-N3 site requires homogeneous distribution of C and N atoms in the support, whereas the local aggregation of C-atoms into "graphene-like island" diminishes the catalytic performance. Fe-N3 site with homogeneously distributed C and N atoms in the support exhibits catalytic activity an order of magnitude higher than that of Fe-N4; while Fe-N3 site with nearby "graphene-like island" in support shows similar or even lower catalytic activity than that of Fe-N4. Fe(IV)=O is identified as the predominant active species responsible for pollutant degradation, and the theoretical simulation reveals that the surrounding molecular configuration of Fe-N3 critically influences the thermodynamics of Fe(IV)=O formation. These findings underscore the importance of jointly regulating the coordination geometry and the molecular features of the support for designing an efficient single-atom catalyzed water treatment process.

Strong metal-support interaction (SMSI) can lead to formation of suboxide overlayers, coating metal particles and reducing their accessibility. Here, we report that on Ni/MoO2 an encapsulated Ni@MoOx structure forms owing to the SMSI effect during reduction and CO2 hydrogenation reaction, while H2O vapor treatment dramatically removes the MoOx overlayer by transforming MoO2 and Mo4O11 into MoO3. This reconstruction facilitates monodentate-formate-mediated CO2 methanation. The optimized 15Ni/MoO2 catalyst treated with 50% H2O vapor switches the selectivity from similar to 100% of CO to 98.2% of CH4. This work establishes an effective strategy for tuning SMSI by H2O-induced reconstruction to develop CO2 methanation catalysts.

Flash Joule Heating (FJH) represents a disruptive strategy for accessing nonequilibrium materials, yet atomic-scale interfacial evolution under subsecond thermal shocks remains poorly understood. Herein, millisecond FJH is employed to freeze critical metastable interfaces, unraveling the kinetic origin of stable sodium-ion storage in Sn-based anodes. Crossvalidation by 119Sn Mössbauer and X-ray photoelectron spectroscopies reveals a unique Sn–C bridging state (isomer shift ~1.2 mm s-1) that effectively suppresses volume expansion upon cycling. Notably, tuning pulse duration uncovers nonlinear kinetic evolution: metastable Sn–C structural peak at 200 ms (11.1%) and decreases sharply beyond this window due to thermodynamic relaxation or disorder reconstruction. This optimized flash-frozen interface establishes a synergistic mechanism: robust Sn–C interactions maintain structural integrity, while the Sn2+/Sn4+ dual-buffering environment enables ultrafast lattice migration, enhancing cycling stability. The engineered electrode exhibits a self-regulating behavior, achieving a highly stable electrochemical equilibrium and superior capacity retention over 700 cycles. This work provides a spectroscopic blueprint for metastable interface engineering and a universal paradigm for fabricating metal composite electrodes via FJH.

Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.

A facile photo-assisted strategy was developed for the in situ anchoring of Co2+ ions onto anatase TiO2nano-particles through photoinduced electron transfer under UV irradiation, enabling the formation of stable Co-O-Ti interfacial bonds while preserving the anatase crystal structure. The Co2+-implanted TiO2nanoparticles were synthesized using the [Co(tn)2(4-Mepy)Br]Br2complex as a precursor in an aqueous electrolyte under UV irradiation and subsequently characterized by XRD, TEM, EDS, FTIR, and XPS analyses, confirming the successful implantation of cobalt under mild reaction conditions. The resulting Co-TiO2 nanoparticles exhibited pronounced room-temperature ferromagnetism, with saturation magnetizations (Ms) of 7.88 & times; 10-3 and 55.41 & times; 10-3 mu B per Co2+ and coercive fields (Hc) of 50.39 and 622.91 Oe for 0.37% and 0.68% Co doping, respectively, in contrast to the diamagnetic behaviour of pristine TiO2. In addition to the enhanced magnetic properties, the Co-TiO2heterostructures exhibited bifunctional electrocatalytic activity toward both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media, delivering over-potentials of 277.3 and 328.6 mV at 10 mA cm-2 with corresponding Tafel slopes of 89.7 and 94.2 mV dec-1 , respectively. The present facile room-temperature strategy simultaneously tailors the magnetic and electrocatalytic properties of TiO2, highlighting the potential of Co-TiO2 nanostructures for multifunctional magnetic and energy-conversion applications.

To enable the efficient storage, retrieval and reuse of data records deposited in data repository systems regarding traditional laboratory Mössbauer spectroscopy measurements, a corresponding comprehensive framework has been developed, which provides a simple yet versatile approach for describing the measured sample, experimental conditions, spectral data, theoretical models, and associated metadata. Experimental details and common data treatment procedures in laboratory Mössbauer spectroscopy were considered to identify the metadata necessary for a thorough characterization of measurements, facilitating the reproducibility and replicability of the results. A grouping of metadata and related information according to their subject is proposed. Based on these groups, a record structure is defined that is divided into several segments, with each segment containing the metadata of a specific group. The precise description of theories used to analyze Mössbauer spectra is proposed to rely on established encoding systems employed by existing Mössbauer spectral analysis software to represent the fit models they are designed to handle. Nevertheless, to define a standardized theoretical baseline, a simplified representation of common special cases of 57Fe and 119Sn Mössbauer spectral fitting models is proposed, ensuring compatibility with a wide range of existing spectral analysis software. Although the developed framework currently focuses on traditional laboratory Mössbauer spectroscopy, it is designed to enable future expansion to closely related methods, such as synchrotron radiation-based Mössbauer spectroscopy.

In contrast to conventional mineralization processes, oxidative polymerization emerges as a transformative pathway within advanced oxidation processes (AOPs), offering distinct advantages such as reduced oxidant consumption, substantial reduction in carbon emissions, and potential for organic carbon recycling. These features highlight its promise as a sustainable and environmentally efficient strategy for pollution control. This review provides an in-depth examination of polymerization mechanisms within AOPs, addressing both chaingrowth and stepwise polymerization pathways, as well as reactive oxygen species induced polymerization, including free radical and non-radical mediated processes (high-valent metal-oxo species, electron transfer pathway, and singlet oxygen mediated polymerization). The review further classifies and investigates the polymerization behaviors of various organic pollutants-phenolic, olefinic, aniline, and heterocyclic compounds, emphasizing the role of molecular structure in dictating polymerization pathways. Essential physicochemical factors influencing polymerization efficiency including reactive oxygen species (ROS) feature and concentration, catalyst properties, and pollutant molecular architecture, are critically assessed. Additionally, the review explores advanced strategies for recovering and characterizing polymerized products, shedding light on their potential applications in pollutant enrichment, resource recovery, and sustainable environmental management. By integrating mechanistic insights with practical applications, this work establishes a framework for leveraging oxidative polymerization in developing low-carbon, high-value environmental remediation technologies.

The twin global challenges of energy scarcity and environmental pollution call for innovative and sustainable technological solutions. Photoelectrocatalysis has emerged as a promising strategy for solar-driven water splitting and environmental remediation, offering an eco-friendly route for hydrogen production and pollutant degradation. At the heart of this progress are hybrid catalysts, which integrate multiple material components to synergistically enhance light absorption, charge separation, and catalytic efficiency. However, optimizing these intricate systems requires a thorough understanding of their behaviour under real-world operating conditions. This review provides a critical overview of the design principles, classifications, and synthesis methods of hybrid photoelectrocatalysts, with particular attention to their applications in water splitting and environmental cleanup. Special emphasis is placed on the use of real-time (in-situ and operando) spectroscopic techniques such as X-ray absorption, Raman, Mössbauer and transient absorption spectroscopies, which offer vital insights into active sites, reaction intermediates, and structure–performance relationships. These advanced tools are essential for guiding the rational design of catalysts and enhancing their durability. We also address current challenges, including issues of material stability and the intricacies of real-time analysis, and highlight emerging directions such as artificial intelligence-driven catalyst discovery and the integration of multiple spectroscopic methods. By bridging materials engineering with mechanistic insight, this review outlines a roadmap for developing next-generation photoelectrocatalysts aimed at scalable, sustainable solutions for energy and environmental needs.

While the effects of Sr segregation on the performance and stability of perovskite electrodes in solid oxide electrolysis cells (SOECs) have been widely studied, most attention has been focused on surface Sr segregates, with the impact of the resulting Sr deficiencies within the bulk phase of the electrodes largely ignored. Here, we report our findings from an investigation into the impact of Sr deficiencies in the SrCo0.7Fe0.3O3-delta (SCF) lattice and surface Sr segregates on the electrochemical behavior of well-controlled anode materials. Results demonstrate that Sr deficiencies in the perovskite lattice significantly enhance bulk oxygen ion transport, while surface Sr segregates suppress oxygen vacancy formation at interfaces, resulting in a reduced rate of oxygen exchange and lower surface electrical conductivity. Our study provides critical insights into the roles of bulk Sr deficiencies and surface Sr segregates, particularly their effects on oxygen vacancy formation, electrical conductivity, oxygen ion transport, and the overall rate of a high-temperature oxygen evolution reaction.

The electrocatalytic activity of perovskite oxides is fundamentally governed by their electronic structure. However, a deeper understanding of the relationship between the eg electron occupancy and high-temperature oxygen evolution reaction (OER) performance in solid oxide electrolysis cells (SOECs) remains underexplored. Here, A-site doped Pr0.5Ae0.5FeO3-δ (Ae = Ca, Sr, Ba) are constructed with exceptional high-temperature OER performance, and Pr0.5Ba0.5FeO3-δ achieves a current density of 3.33 A cm-2 at 2.0 V and 800 °C. X-ray absorption spectroscopy, 57Fe Mössbauer spectroscopy, and magnetic susceptibility measurements reveal that alkaline earth metal doping induces a spin-state transition from high-spin Fe3+ (t2g3eg2) to low-spin Fe4+ (t2g4eg0), with reduced eg occupancy, thus accelerating the charge transfer and oxygen transport in the OER process. This work sheds light on the critical role of the B-site Fe electronic structure in high-temperature OER performance and provides guidance for the rational design of Fe-based perovskites as SOEC anode materials.

Metal (hydro)oxides are among the most effective heterogeneous water oxidation catalysts. Elucidating the interactions between oxygen-bridged metal sites at a molecular level is essential for developing high-performing electrocatalysts. Here we demonstrate that adjacent metal-hydroxyl groups function as intramolecular proton–electron transfer relays to enhance water oxidation kinetics. We achieved this using a well-defined molecular platform with an aza-fused π-conjugated microporous polymer that coordinates molecular Ni or Ni–Fe sites that emulate the structure of the most active edge sites in Ni–Fe materials for studying the heterogeneous water oxidation mechanism. We combine experimental and computational results to reveal the origin of pH-dependent reaction kinetics for O–O bond formation. We find both the anions in solution and the adjacent Ni3+–OH site act as proton transfer relays, facilitating O–O bond formation and leading to pH-dependent water oxidation kinetics. This study provides significant insights into the critical role of electrolyte pH in water oxidation electrocatalysis and enhancement of water oxidation activity in Ni–Fe systems. Intramolecular proton relays are proposed to enhance oxygen evolution for heterogeneous (hydro)oxide electrocatalysts, but molecular-level evidence remains limited. Now it has been shown, using an aza-fused microporous polymer with Ni–Fe sites, that adjacent Ni3+–OH sites relay protons from Fe⁴⁺=O, accelerating the water nucleophilic attack pathway and achieving high turnover frequencies with pH-tunable kinetics.

Precise manipulation of the catalytic spin configuration and delineation of the relationship between spin related properties and oxidation pathways remain significant challenges in Fenton-like pro-cesses.Herein,encapsulated cobalt nanoparticles and cobalt-nitrogen-doped carbon moieties,en-dowed with confinement effects and variations in shell curvature were constructed via straightfor-ward pyrolysis strategies,inducing alterations in magnetic anisotropy,electronic energy levels and spin polarization.The enhanced spin polarization at cobalt sites leads to a reduction in crystal field splitting energy and an increase in electronic spin density.This phenomenon facilitated electron transfer from cobalt orbitals to pz orbitals of oxygen species within peroxymonosulfate molecules,thereby promoting the formation of high-valent cobalt species.The encapsulation effectively stabi-lized cobalt nanoparticles,mitigating their dissolution or deactivation during reactions,which in turn enhances stability and durability in continuous flow processes.The high-valent cobalt species within the shell exhibit increased exposure and generate localized high concentrations,thereby intensifying interactions with migrating pollutants and enabling efficient and selective oxidation of emerging compounds with elevated redox potentials.This work underscores the profound impact of confined encapsulation curvature and spin polarization characteristics of metal sites on catalytic oxidation pathways and performance,opening novel avenues for spin engineering in practical en-vironmental catalysis.

Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications. Constructing and regulating the strong metal-support interactions (SMSI) by diverse methodologies has emerged as one of the promising approaches to fabricating robust supported metal catalysts. In this study, we report an L-ascorbic acid (AA)-inducing strategy to generate SMSI on a titania-supported gold (Au) catalyst after high-temperature treatment in an inert atmosphere (600°C, N2). The AA-induced SMSI can efficiently stabilize Au nanoparticles (NPs) and preserve their catalytic performance. The detailed study reveals that the key to realizing this SMSI is the generation of oxygen vacancies within the TiO2 support induced by the adsorbed AA, which drives the formation of the TiOx permeable layer onto the Au NPs. The strategy could be extended to TiO2-supported Au catalysts with different crystal phases and platinum group metals, such as Pt, Pd, and Rh. This work offers a promising novel route to design stable and efficient supported noble metal catalysts by constructing SMSI using simple reducing organic adsorbent.

Highly active and durable Fe-N-C electrocatalysts toward acidic oxygen reduction reaction (ORR) remain challenging due to their inferior intrinsic activity, low density, and insufficient exposure of active sites. Herein, we report the pyrolysis of coassembled hemin and copolymer capping on Zn(OH)2 nanosucculent plants, leading to the synthesis of highly porous ultrathin carbon nanoshells comprised of rich atomically dispersed Fe-N-C sites. The nanoshell is about 5.5 +/- 0.8 nm thick with a pore volume of 0.5 cm3 g-1, allowing sufficient exposure of active sites. The nanoshell shows a remarkable ORR half-wave potential (E 1/2) of 0.871 V (vs a reversible hydrogen electrode, RHE). The activity originates from the highest intrinsic activity with a turnover frequency of 11.7 e- site-1 s-1 at 0.8 V (vs RHE) and abundant accessible active sites (2.37 x 1020 g-1). Density functional theory elucidates that the presence of about 4 & Aring; micropores neighboring to Fe-N-C lowers the Gibbs free energy of the ORR rate-determining step (O* + H+ + e- = OH*), which is beneficial for the improvement of intrinsic activity. Moreover, the nanoshell demonstrates a durability with 36 mV of E 1/2 decay superior to that of commercial Pt/C (47 mV) during accelerated durability tests. Eventually, the remarkable activity was embodied by a peak power density of 450.6 mW cm-2 in H2-air single cells.

The strong metal-support interaction (SMSI) is able to regulate the electron and geometric structure of supported metal catalysts to improve their performance. However, conventional SMSI formation typically requires hightemperature reduction or oxidation treatments, making it challenging to prevent particle sintering before its establishment. Here, we propose a rapid and energy-efficient microwave treatment to induce SMSI in an Au/ CeO2 system under ambient conditions. Comprehensive characterization confirms that the encapsulation of Au nanoparticles (NPs) and the reduced CO adsorption capacity align with the characteristics of classical SMSI. The rapid generation of oxygen defects and Ce3 + species in the support is the key to enabling microwave-induced SMSI. As a result, the Au/CeO2-MW5 catalysts associated with this SMSI demonstrate excellent stability during a 100-hour test. In addition, this strategy is extendable to various Au-based catalysts supported on metal oxides, such as Au/TiO2 and Au/ZrO2. This work offers an efficient and facile approach to constructing SMSI, potentially laying the foundation for developing encapsulation to enhance the catalyst's stability of noble metal catalysts.

Ethanol synthesis via dimethyl oxalate hydrogenation has garnered increasing attention in the fields of syngas utilization. Although s-Fe2C has been identified as a promising active species for DMO hydrogenation to ethanol, its formation is kinetically challenging during carbonization. In this work, a Fe4N phase was first synthesized by pretreating a 30Fe/SiO2 catalyst in an ammonia environment, followed by carbonization in a methanol-H2 flow to obtain s-Fe2C as the active phase. Fe4N, rather than Fe-O-Si, facilitates the transformation into iron carbide during the carbonization process. The transformation pathway of iron nitride (FexN) is mediated by intermediate iron carbonyl species (Fe-CO), ultimately leading to the formation of iron carbide as the active phase. The resulting catalyst exhibited 40 times higher catalytic activity than the untreated catalyst in DMO hydrogenation. Combined structure properties and DFT calculation revealed that the lower energy barrier of s-Fe2C for ester hydrogenation underpins/ strengthens its superior performance, while the STY of s-Fe2C is 2.8 times that of s '-Fe2.2C and 58 times that of x-Fe5C2. This study provides a novel strategy for designing highly efficient iron carbide catalysts for the esters hydrogenation system. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.