High-valent metal-oxo species are potent nonradical active species that considerably enhance advanced oxidation processes (AOPs) owing to their long half-lives and selective oxidation of electron-rich pollutants. However, in peroxymonosulfate (PMS)-based AOPs, targeted Co(IV) = O generation is intrinsically limited by the activity-selectivity trade-off arising from mismatched energy barriers between PMS adsorption and product desorption, coupled with suboptimal synergy in Co spin polarization and d-band center modulation. To address these issues, a bimetallic Cu/ZIF-67 template was doped with N atoms. The strong electronegativity of N downshifted the Co d-band center in Cu/ZIF@N1.5 by 0.56 eV relative to Cu/ZIF-67, thereby tuning the PMS adsorption energy from -7.87 to -1.23 eV and shifting the adsorption from strong to moderate. This reduced the desorption energy barrier for O-O cleavage products, while enhanced Co spin polarization accelerated interfacial electron transfer kinetics, driving rapid PMS transformation via the adsorption-dissociation-Co(IV) = O generation pathway. The resultant Co(IV) = O species selectively oxidized tetracycline via O-atom transfer, increasing the degradation rate constant by 19.4-fold relative to undoped Cu/ZIF-67, thereby substantially boosting intrinsic catalytic activity. These findings deepen the molecular-level mechanistic understanding of PMS activation and offer new perspectives for the rational design of high-efficiency environmental catalysts.

Nonradical oxidation pathways exhibit strong resistance toward water matrices in periodate (PI) activation for emerging contaminants (ECs) degradation, thereby offering a promising strategy for water purification. Notably, metal-N structures have been widely reported as the dominant active sites in PI activation, steering the reaction toward the nonradical pathways. In this work, abundant and stabilized Fe-Nx sites were achieved through the synergistic effect of dual confinements: carbon confinement from nitrogen-rich biomass-derived biochar (NBC) and structural confinement from the thermal transformation of an iron-containing metal-organic framework (MOF-Fe) during pyrolysis. On this basis, a carbon-encapsulated nano-iron catalyst (FeC@NBC) was constructed and exhibited excellent performance in activating PI for the degradation of ECs. Mechanistic studies revealed that the oxidation pathway is predominantly driven by the inner electron transfer process (ETP) with Fe-Nx sites being the primary active sites, as confirmed by experimental and theoretical investigation. In parallel, IO3 center dot plays a minor role, with Fe0 serving as its primary active sites. Moreover, the organic ligands in the MOF precursor solution, which are rich in aromatic or unsaturated structures, regulated the carbon structure during pyrolysis. This promotes the formation of C=C bonds that facilitate electron conductivity, thereby enhancing the ETP efficiency. FeC@NBC/PI exhibited superior degradation efficiency for electron-rich pollutants, broad pH applicability, stable cycling performance, and strong resistance to inorganic anion and natural organic matter. Toxicity assessments, life cycle assessment and continuous-flow reactor experiments further demonstrated its potential for practical water treatment.

The coexistence of iron and nitrate (NO3-) in natural and engineered environments invites complex abiotic and biotic interactions, yet how such abiotic-biotic synergies operate under fluctuating carbon availability and how light modulates them remain poorly resolved. Using a nitrate-reducing, nitrite-accumulating enrichment culture derived from lake sediment, we uncovered a synergistic abiotic-biotic relay that overcame the kinetic bottleneck of denitrification. During initial heterotrophic denitrification of 2 mM NO3-, 85.10-89.72% of the substrate was accumulated as NO2-. In contrast, ferrous iron (Fe(II)) amendment triggered subsequent iron-dependent nitrate reduction (IDNR) and significantly reduced NO2- accumulation. Abiotic controls confirmed that Fe(II) chemically reduced the accumulated NO2⁻ to the downstream products. In parallel, metagenomic and metatranscriptomic analyses of the bioactive samples demonstrated that these gaseous intermediates (e.g., NO, N2O) were enzymatically reduced to N2 based on upregulated denitrification-associated genes. More importantly, when exogenous acetate was depleted, the community sustained IDNR not through strict autotrophy but via heterotrophic metabolism using intracellular poly-3-hydroxybutyrate (PHB) and microbial necromass as the carbon/energy sources. This metabolic plasticity drove a functional succession from organotrophic denitrifiers (e.g., Pseudomonas) toward PHB- and necromass-utilizing microbial consortia mainly composed of Pseudomonas, Alicycliphilus and some phototrophic populations. Supporting evidence showed that illumination further accelerated the relay via light-driven reactive oxygen species, and secondary iron minerals (e.g., bernalite, lepidocrocite, and goethite) formed as fingerprints of the Fe(II) oxidation. Collectively, this work deciphers a dual-mechanism model, abiotic nitrite reduction followed with endogenous carbon-fueled denitrification, that governed efficient nitrate reduction under carbon-limited conditions. Leveraging such abiotic-biotic relays offers promising strategies for sustainable nitrogen removal in both natural and engineered systems.

Singlet oxygen (1O2) mediated non-radical pathways in peroxymonosulfate (PMS) activation process is crucial for selective degradation of organic pollutants. However, the rational design of catalysts for efficiently and selectively generating 1O2 remains a significant challenge. In this work, we address this challenge by employing a spatial confinement pyrolysis strategy to fabricate cobalt nanoparticles (NPs) embedded in nitrogen-doped carbon (Co@CN). The embedded Co NPs tightly contact with carbon layer via Co-N/C bond connecting. The optimal 0.8Co@CN exhibited the highest PMS activation performance for sulfamethoxazole (SMX) degradation, achieving 100% removal within 20 min. The first-order kinetic constant was 19.6 times higher than that of cobalt-free nitrogen doped carbon (CNs). Results reveal that 1O2 dominated in SMX degradation. Theoretical and experimental results revealed that a Co-N/C interface structure formed between the embedded Co NPs and the graphitic nitrogen-doped carbon layer, which might act as an electron transport bridge that facilitates the transfer of electrons from PMS adsorbed on the carbon surface to Co3+ ions within the Co NPs, thereby activating PMS into SO5•−and subsequently generating 1O2. The highly selective generation of 1O2 enables the system to selectively degrade electron-rich organic compounds and exhibits good anti-interference capability against co-existing ions in natural water. Furthermore, the system demonstrated excellent SMX degradation performance over a wide pH range (4.5–8.5) and outstanding stability, maintaining approximately 90% SMX removal during 10 h of continuous operation. This study provides an active-site-confined cobalt-encapsulated carbon catalyst that enables efficient and stable 1O2 production in PMS activation-based Fenton-like reactions for organic pollutants removal.

Improving the efficiency of inverted perovskite solar cells (PSCs) is crucial for promoting their commercialization. The alpha-FAPbI3 shows huge promise as an absorber, however, its unfavored energetically at room temperature make the preparation of high-quality alpha-FAPbI3 a challenge. In this work, the dual-additives were utilized to enhance the phase purity of alpha-FAPbI3, and the underlined synergism was revealed. Both experimental measurement and theoretical calculation conformed that the dual-additives of MACl and PbCl2 can synergistically enhance the ability to accelerate the direct formation of alpha-FAPbI3 through largely reducing its formation energy, and inhibit the undesired S-phase that inevitably occurs neither which additive is utilized singly. This synergism of dual-additives supports to realize a high-quality perovskite films with enhanced phase purity, and reduced defect density. As a consequence, the inverted PSCs achieve an impressive efficiency of 26.17 %, and the unencapsulated device can maintain 93 % of their initial PCE after 2000 h of storage in ambient air at 20 % RH and 25 +/- 5 degrees C.

A photocatalyst composed of indium-zinc-sulfide quantum dots modified inverse opal titanium dioxide (ZIS QDsIOT) was synthesized and utilized for the degradation of various organic dyes under sunlight. Electron microscopy images revealed uniform dispersion of ZIS QDs, ranging in size from 2 to 5 nm, on the surface of IOT within an orderly three-dimensional porous structure. Photocatalytic tests demonstrated that the apparent kinetic constants of ZIS QDs-IOT were 19, 8, and 7 times higher than those of bare IOT, ZIS QDs, and commercial P25, respectively, indicating its substantial potential as a non-toxic and stable photocatalyst. Further characterizations indicated a significant enhancement in the production of photoinduced charges, along with a directional electron transfer from IOT to ZIS. Moreover, increased generation of oxidative species resulting from the oxygen reduction process was observed in the composite compared to IOT. Electrochemical analyses and theoretical calculations corroborated the accelerated oxygen reduction process upon the addition of ZIS QDs to IOT. Consequently, a Zscheme route for photoinduced charge transfer was established in the ZIS QDs-IOT composite, leading to prolonged lifetime and reduced recombination rate of photoinduced charges. This synergistic effect preserved the highly oxidative and reductive abilities of both semiconductors, ultimately resulting in remarkable photo- catalytic activity.

The lifetime of free radicals limits the effectiveness of catalytic degradation reactions and the efficient utilization of transient free radicals remains a significant challenge in current research. In this paper, we have developed MIL-125 MOF derivatives, which can influence the morphology and structure of the materials by controlling the calcination time. The CT3 system significantly enhanced the activation performance of persulfate (PDS) and enabled the complete degradation of acetaminophen (ACT) within 20 min. The electron acceptor effect of the C--C double bond accelerates the generation of singlet oxygen in the CT3 system, and rapidly acts on ACT, thereby improving the degradation performance of the CT3 system. Product analysis and soybean seed germination experiments confirmed that the toxicity of the degradation products was significantly reduced, and the degraded solution did not affect soybean growth. This study offers novel approaches and insights for utilizing MOF derivatives to activate PDS for the degradation of organic contaminants.

The cobalt-carbon composite (C@Co) stands out as an ideal catalyst for generating high-valent cobalt-oxo (Co (IV)=O) species during peroxymonosulfate (PMS) activation, however, its application is badly constrained by the disadvantages of the inefficiency and unstable of Co(IV)=O generation, along with the challenge of recycling. To solve this limitation, in this work, Ni in-situ doped C@Co grown on nickel foam (C@CoNi/NF) was fabricated. The C@CoNi/NF-700 prepared at 700 degrees C had the highest PMS activation efficiency toward bisphenol A (BPA). Almost 100 % of BPA can be removed in 100 s with the first-order reaction constant (kobs) of 3.98 x 10-2 s-1. It was revealed that the Co(IV)=O played the pivotal role in BPA degradation with the contribution being 97.60 %. This led to the system exhibited high selective oxidation for organics, excellent anti-interference capabilities for co-existing ions in real water, wide pH adaptability and high stability. Theoretical calculation results showed that Co(IV)=O was generated with the cleavage of S-O and O-O bonds of PMS, which was totally different from the previous studies via the O-O and O-H bond cleavage. Additionally, the doped Ni0 can lower the reaction energy barrier of Co(IV)=O generation of C@Co. Finally, the continuous-flow experiment revealed the C@CoNi/NF-700 + PMS system exhibited a long-term stability and has a promising potential in practical purifying wastewater. This work not only developed one stable and easily recovery catalyst for rapidly selectively removing organics in wastewater, but also provided new insights into the Co(IV)=O generation pathway in PMS based AOPs.

Activation of peracetic acid (PAA) by Fe(II) ([Fe(II)-PAA]) can produce multiple free radicals, which is an emerging advanced oxidation process (AOPs) for the efficient removal of recalcitrant organics. But most studies have focused on the high-valent metals and neglected the role of center dot OH. This study re-examined the role of active oxidation species produced by the [Fe(II)-PAA] system in the degradation of aniline. Benefiting from the synergistic effect of Fe(IV)=O and center dot OH, [Fe(II)-PAA] system can remove 96.7 % of aniline within 5 min, and the first-order kinetic constant can reach 8.13 x 10- 1 min- 1. The theoretical calculation revealed Fe(IV)=O was produced via Fe(II) activating PAA, but center dot OH is produced via Fe(IV)=O instead of directly from PAA activation, which was different from the previous reports. Furthermore, the [Fe(II)-PAA] system exhibited excellent aniline degradation efficiency in a wide range of pH and in complex water matrices, meanwhile, the system can degrade aniline into the less toxic products. It indicated the system has an attracting potential for practical application. Additionally, the degradation of serials pollutants with diverse properties by the [Fe(II)-PAA] system also investigated. This study not only provides one efficient technology for ultra-fast removing aniline, but also enriches the mechanism research on transition metal activation of PAA.

In this work, manganese (Mn) with different contents doped CNs (CNs-Mn) was prepared via the thermal polymerization of the mixture of melamine, beta-lactose and manganese sulfate and used as peroxymonosulfate (PMS) activator for sulfadiazine (SD) degradation. The optimum CNs-Mn(ii) delivered admirable PMS activation efficiency toward SD degradation and the contents of oxidized N and Mn2+ in catalysts displayed strongly positive correlation with SD degradation constant. Electron paramagnetic resonance (EPR) and quenching experiments revealed that the content of generated O-1(2) species was higher than other radicals and O-1(2) dominated SD degradation in the CNs-Mn(ii)/PMS system. The density functional theory (DFT) calculation analysis revealed a novel direct evolutionary pathway of O-1(2) formation, that is the cleavage of S-O and O-H of PMS lead to two O atoms to form O-1(2). Furthermore, CNs-Mn(ii) displayed good stability, anti-interference ability and performed well in the wide pH range of 4.5 similar to 9.5. This study would give new insights into O-1(2) generation mechanism and essential atomic-scale understanding of the roles of oxidized N and Mn species in O-1(2) generation during Mn doped N containing carbon activating PMS process, as well as develop one new strategy to promote O-1(2) generation efficiency.

Atomically dispersed cobalt and nitrogen co-doped carbon catalysts are ideal catalysts for high-valent cobalt-oxo (Co(IV)(sic)O) species generation in peracetic acid (PAA) activation, however, the stability and catalytic efficiency remain unsatisfactory. Herein, cobalt nanoparticles (NPs) embedding into the atomically dispersed cobalt-nitrogen-biochar (N-Co-BC@Co) were fabricated to promote Co(IV)(sic)O generation during PAA activation to efficiently remove organics. The optimum N-2Co-BC@Co/PAA exhibited promising PAA activation performance (bisphenol A (BPA) = 10 mg/L, 99.3 % in 15 min) with low Co leaching (<0.1 mg/L). Co(IV)(sic)O species were determined to dominate organics degradation in the N-2Co-BC@Co/PAA system. Theoretical calculations revealed that the embedded cobalt NPs could reduce the energy barrier for Co(IV)O generation. Furthermore, N-2Co-BC@Co was loaded on carbon fibers for use in continuous flow devices, demonstrating the excellent long-term stable removal of organic pollutants. In addition, this system exhibited excellent anti-interference of coexisting matter in water except Cl- and HPO42- which was ascribed to the decreased PAA consumption by HPO42- and the impeded BPA adsorption by HPO42- and Cl- on catalyst. This study offers novel insights into the strategy of promoting Co(IV)(sic)O species generation during PAA activation and proposes an efficient and stable catalyst for the practical purification of wastewater via PAA based advanced oxidation processes.

Cathode electrochemical catalysis (EC) coupled with the activation of peroxydisulfate (PDS) (EC/cathode/PDS) is considered an effective method for removing persistent organic compounds from water. Bimetallic FeMncarbon composites grown on nickel foam (NFO) (C-FeMn-NFO) cathode with varying Fe/Mn molar ratios were synthesized to efficiently activate PDS during the EC/cathode/PDS process. The optimum C-FeMn-NFO cathode with the Fe/Mn molar ratio being 90:10. Almost 100 % of sulfamethoxazole (SMX) was removed by the EC/C-FeMn-NFO/PDS system within 15 min, which was much higher than that by the EC/C-Fe-NFO/PDS and EC/C-Mn-NFO/PDS system. Singlet oxygen (1O2) made a dominant contribution to SMX degradation, which being further evidenced by the high selectivity for organic oxidation in the EC/C-FeMn-NFO/PDS system and the Fe0, Mn2+ and Mn3+ were main active sites for PDS activation. Experiment and Density functional theory (DFT) calculation results indicated that the co-presence of Fe and Mn promotes the PDS adsorption, thus more PDS was consumed to produce more 1O2. In addition, this system displayed robust resistance to interference from ions in natural water, excellent stability, and low energy consumption. Finally, a potential degradation pathway for SMX was proposed based on identified degradation intermediates and theoretical calculations, along with an assessment of the toxicity of these intermediates. This study has developed an efficient cathode material that enhanced the organic removal by the EC/cathode/PDS system.

Piezo-photocatalysis technology can convert both mechanical energy and solar energy into chemical energy, which has important application value in environmental remediation. However, the activity of piezoelectric catalysts is limited by weak piezoelectricity, resulting in low efficiency in generating photogenerated electron-hole pairs and difficulty in carrier migration. This work achieved piezo-photocatalytic degradation of tetracycline and H2 production via the synergistic effect of defects and piezoelectric polarization, and further revealed the synergistic catalytic reaction mechanism of SrTiO3 (STO). The introduced oxygen vacancy defects changed the local dipole state, which was beneficial for enhancing the piezoelectric polarization of STO, and promoted the separation of photogenerated carriers and the generation of effective active oxygen species (such as photogenerated holes and superoxide radical). This study sheds light on the rational design of defect-based piezoelectric catalysts to enhance piezo-photocatalytic performance.

The development of efficient photocatalytic methods for the degradation of neonicotinoid insecticide contamination and the reduction of its toxicity presents significant challenges. Although oxygen vacancies can enhance catalytic performance, they often destabilize the catalyst. In this study, we constructed a self-recovering porous BiOCl with oxygen vacancies (POv-BOCs), which forms an in-lattice electron donor-acceptor system under visible light. In this system, the donor lattice oxygen donates electrons to generate oxygen, while the acceptor lattice Bi accepts these electrons to produce metallic Bi0. The released oxygen is captured by Bi0, which replace the oxygen vacancies as active sites, thereby endowing POv-BOCs with enhanced stability. The electrophilic characteristics of POv-BOCs significantly improve the degradation performance of neonicotinoid insecticides, and the degradation rate exhibited a positive correlation with their electronic affinity value. Although some nitrated byproducts formed during the degradation process initially increased toxicity, the persistent action of POv-BOCs ultimately induced toxicity reduction. This work presents an effective approach to enhancing the stability and photocatalytic performance of oxygen vacancies, which are highly significant for developing of oxygen vacancy catalytic systems and the degradation of electron-deficient pollutants.

Imitating the multinodal structures of plants and arthropods, precisely engineered multisegment nanostructures demonstrate enhanced synergistic properties and exceptional functionalities that surpass those of individual components. Utilizing micelle assemblies for constructing segments allows for precise structural control but requires management of interactions and assembly from molecular to mesoscopic levels, posing a significant challenge. In this paper, we present a stepwise self-assembly strategy to fabricate multisegment mesoporous silica (mSiO2) nanobamboos. The nanobamboos are characterized by 16-25 shuttle-shaped mesoporous segments connected end-to-end in line, forming the main chains with an overall length of approximately 0.7-1.0 μm. Each individual segment is composed of 10-13 parallel layers, with an average layer thickness of ∼2.5 nm. The formation of this multisegment mesoporous nanobamboos, as proven by in situ testing, is initiated by the formation of shuttle-shaped segments from small bilayer micelle units, which then further assemble to form the nanobamboo. This stepwise self-assembly can be regulated from a kinetic perspective, thereby obtaining multisegment mesoporous nanostructures with varying lengths and branched morphologies. Due to multiple segments along with multilayer mesostructures, the nanobamboos can significantly restrict gas flow, resulting in a very low thermal conductivity (∼41.67 mW·m-1·K-1). By blending the multisegment mSiO2 nanobamboos with cellulose nanofibers, mechanically stable, lightweight, and porous aerogels with an ultralow thermal conductivity (∼19.85 mW·m-1·K-1) can be obtained, verifying their potential in thermal insulation devices. The fabrication of this multisegment mesoporous nanobamboos enhances our understanding of micro-to-nanoscale assembling, establishing a foundation for precise control of complex structures.

The high-valent iron-oxo species (Fe(IV) = O) as the dominant reactive species limits the application due to Fe (IV) = O's moderate oxidation potential and the potential formation of highly toxic intermediates. To address this, H2O2 was introduced into the [Fe(II)-PAA] process (denoted as [Fe(II)-PAA-H2O2]) to promote hydroxyl radicals (center dot OH) generation instead of Fe(IV) = O. The [Fe(II)-PAA-H2O2] system achieved a degradation efficiency of 98 % for aniline within 100 s, with the second-order kinetic rate constant being 6.4 times higher than that of the [Fe(II)-PAA] system. Theoretical calculations thermodynamically demonstrate that H2O2 presence benefited in the direct center dot OH generation instead of Fe(IV) = O formation as reported in previous studies. The process exhibited satisfactory efficiency across a broad pH range and in complex water matrices, and it demonstrated that all degradation products of aniline by this system are non-toxic. This work provided a simple and effective strategy to enhance center dot OH production in Fe(II)/PAA processes, offering significant potential for practical water treatment applications.

The formation of porosity within nanoparticles via dealloying is notably constrained by the dimensions of the precursor particles, a limitation stemming from the surface kinetic processes occurring during dealloying. In this study, we present a straightforward methodology, specifically tailored for fabricating diminutive nanoporous alloy nanoparticles, originating from their small-sized precursor counterparts. We initiated our research with precursor PtNi alloy nanoparticles, which possess an average diameter of 9 nm. By incorporating an extrinsic metal, Ir, known for its slower surface diffusion on the nanoparticle surface, we successfully modulated the surface migration velocity of Pt during the dealloying process of the PtNi alloy nanoparticles. This precise manipulation led to the formation of an abundantly complex nanoporous structure on diminutive PtNi nanoparticles. Owing to their enhanced high surface area-to-volume ratio and the synergistic alloy effect, electrochemical tests revealed that the Ir-coated diminutive nanoporous PtNi nanoparticles exhibit superior electrocatalytic activities towards oxygen reduction and formic acid oxidation reactions. Furthermore, the presence of Ir on the surface effectively suppresses the surface diffusion rate of Pt, thereby significantly inhibiting the coarsening evolution of the porous metallic structure. This intervention ensures the long-term preservation of both structural integrity and catalytic stability.