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Due to the limited semantic information extraction with small objects and difficulty in distinguishing similar targets, it brings great challenges to target detection in remote sensing scenarios, which results in poor detection performance. This paper proposes an improved YOLOv5 remote sensing image target detection algorithm, SEB-YOLO (SPD-Conv + ECSPP + Bi-FPN + YOLOv5). Firstly, the space-to-depth (SPD) layer followed by a non-strided convolution (Conv) layer module (SPD-Conv) was used to reconstruct the backbone network, which retained the global features and reduced the feature loss. Meanwhile, the pooling module with the attention mechanism of the final layer of the backbone network was designed to help the network better identify and locate the target. Furthermore, a bidirectional feature pyramid network (Bi-FPN) with bilinear interpolation upsampling was added to improve bidirectional cross-scale connection and weighted feature fusion. Finally, the decoupled head is introduced to enhance the model convergence and solve the contradiction between the classification task and the regression task. Experimental results on NWPU VHR-10 and RSOD datasets show that the mAP of the proposed algorithm reaches 93.5% and 93.9%respectively, which is 4.0% and 5.3% higher than that of the original YOLOv5l algorithm. The proposed algorithm achieves better detection results for complex remote sensing images. [ABSTRACT FROM AUTHOR]

Effective bromate removal by supramolecule BDTD photocatalyst. To guarantee drinking water security, removal of bromate (BrO 3 −) has garnered plenty of attention in water treatment. In current study, we have developed a novel conjugated donor-acceptor (D-A) photocatalyst (4,4′'-bis(diphenylamino)-[1,1′:4′,1′'-terphenyl]-2′,5′-dicarbaldehyde, BDTD) with supramolecule architecture assembling via intermolecular C H···O hydrogen bonds and C H···π interactions. Both diffuse reflectance spectrum (DRS) and density functional theoretical (DFT) calculations gave the bandgap of E g = 2.21 eV, clearly indicating the visible-light response of BDTD supramolecule. The calculations showed that BDTD supramolecule could induce nearly 100% removal of BrO 3 − stably at pH-neutral condition driven by visible light, accounting for a first-order kinetic constant being one order of magnitude higher than most of the photocatalysts previous reported. As demonstrated by our electron scavenger experiment and DFT calculations, the BDTD supramolecule should undergo the photocatalytic reduction of BrO 3 − through direct reduced by the lowest unoccupied molecular orbital of conduction band (potential of −1.705 V versus standard hydrogen electrode) electron. The BDTD supramolecule may serve as an attractive photocatalyst by virtue of response to visible light, efficient charge transfer and separation as well as high photocatalytic activity, which will make the removal of BrO 3 − in water much easier, more economical and more sustainable. [ABSTRACT FROM AUTHOR]

Heteroatoms-doped carbon-based materials (with non-precious metals or no metals) with porous structure have already shown high catalytic activities for oxygen reduction reaction (ORR), especially in microbial fuel cells (MFCs). Here, we use pectin extracted from pomelo peels as carbon source to prepare metal-free and sulphur/nitrogen co-doped partially-graphitized carbon (HP-SN-PGCs) by using silica nanospheres as sacrificial templates. Single-chamber MFC (SC-MFC) with HP-SN-PGC-0.5 (0.5 g of silica) cathode has the shortest start-up time (45 h) and lowest charge transfer resistance (19.3 Ω). The maximum power density of HP-SN-PGC-0.5 (1161.34 mW m−2) cathode is higher than that of Pt/C (1116.90 mW m−2) at the initial cycle. After 75 d operation, power density of HP-SN-PGC-0.5 cathode only declines 4.6%, which is more stable than that of Pt/C (37.69%). HP-SN-PGC-0.5 has a highly porous structure (869.25 m2 g−1) by removal of templates and Fe species (as the graphitization catalyst) to facilitate exposure of active sites and diffusion of ORR-related intermediates (OH− and HO 2 −, etc) to accessible active sites. N and S species provide highly active sites to enhance OH− generation to conduct the 4e− ORR process. Thus, this study presents a viable ORR catalyst with high activity and long-term stability for bio-electricity generation from organic wastewater in SC-MFCs. Image 1 • Pectin extracted from pomelo peels is used as carbon source for S, N co-doped carbon. • Template strategy aids to form hierarchical porous carbon for smooth mass transfer. • S and N species in carbon lattice have synergistic effects for boosting ORR activity. • High activity and low H 2 O 2 yield guarantees the fast ORR kinetics via a 4e− pathway. • Porous structure and defects of S, N co-doped carbon affords high property in SC-MFC. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Wasted cornstalk cores are used as carbon source for Fe 3 Se 4 /FeSe/NPGC preparation. • Porous structure and defects (active sites) in carbon skeleton boost ORR activity. • Fe 3 Se 4 /FeSe heterojunctions provide efficient pathways for charge transfer in ORR. • Doped N atoms enhance the charge delocalization of C atoms to reduce electron loss. • High ORR activity of Fe 3 Se 4 /FeSe/NPGC (850 °C) affords high performance in AC-MFC. Abstract Sluggish kinetics of oxygen reduction reaction (ORR) on air-cathode of microbial fuel cells (AC-MFCs) is one of the main obstacles for energy loss. In this study, nitrogen-doped Fe 3 Se 4 /FeSe/partially-graphitized carbon (Fe 3 Se 4 /FeSe/NPGC) composites as non-precious-metal air-cathode (ORR) catalysts are obtained using waste biomass (cornstalk cores) as raw material. As carbonization temperature increases (800–950 °C), the crystalline phase transition between Fe 3 Se 4 and FeSe is strengthened to form the Fe 3 Se 4 /FeSe heterojunctions. The highest power density (1003 mW m−2) and durability (decline of 7.8% after 105 d operation) are obtained by Fe 3 Se 4 /FeSe/NPGC (850 °C) cathode in AC-MFCs, which are higher than those of Pt/C (840 mW m−2, 52.4%). The high ORR activity of Fe 3 Se 4 /FeSe/NPGC (850 °C) is partly attributed to the large specific surface area (356.68 m2 g−1) and porous structure. Doped N atoms (pyridinic N, pyrrolic N and graphitic N) in carbon skeleton enhance the charge delocalization of C atoms to reduce the electron loss to enhance the electron utilization via a four-electron (4e−) ORR pathway. Fe 3 Se 4 /FeSe heterojunctions should greatly promote the charge transfer and oxygen dissociation efficiencies. The highly-conductive NPGC skeleton also contributes to the efficient charge transfer. The good long-term durability of AC-MFCs with Fe 3 Se 4 /FeSe/NPGC (850 °C) cathode is mainly ascribed to its fast ORR kinetics, which still generates a small amount (below 10.0%) of H 2 O 2 (•OH and •O 2 −) intermediate to inhibit the electrogenic microbe growth on cathode surface. This work not only provides the fundamental studies on carbon-supported transition-metal selenides for ORR, but also provides a new kind of promising alternatives for precious metal-based electrodes for AC-MFCs. [ABSTRACT FROM AUTHOR]

Exploration of noble-metal free catalysts with high oxygen reduction reaction (ORR) activity and durability as alternatives for platinum/carbon (Pt/C) in microbial fuel cells (MFCs) remains a great challenge. This study reports the preparation of nitrogen-doped cobalt/cobalt phosphide/carbon (Co/Co 2 P/NC) catalysts via an in situ simultaneous doping/reduction method by using residual cornstalks as carbon source. Effects of carbonization temperature on structural characteristics and catalytic activity of Co/Co 2 P/NC catalysts are investigated. Co/Co 2 P/NC-850 with regular network structure obtains the maximum power density of 972 ± 5 mW m −2 , which is higher than that of Pt/C (808 ± 5 mW m −2 ). The highest Coulombic efficiency (23.1%) and the lowest charge transfer resistance (0.93 Ω) are also obtained by Co/Co 2 P/NC (850 °C). ORR catalyzed by Co/Co 2 P/NC-850 is mainly via 4e − reduction pathway. The better durability of Co/Co 2 P/NC (850 °C) is detected from long-term operation of MFCs. The promising catalytic activity for ORR is attributed to the introduction of Co/Co 2 P nanoparticles/Schottky junctions and N species in porous carbon skeleton, which are served as active sites to trap and consume electrons. Biomass-derived carbon with good electrical conductivity can provide large specific surface area and abundant interconnected holes, which contribute to efficient permeation and transport of O 2 . The synergistic effects between porous structure and sufficient active sites can energetically boost catalytic activity to improve ORR efficiency. These Co/Co 2 P/NC catalysts with durable power outputs are expected to have more extensive applications in MFCs. [ABSTRACT FROM AUTHOR]

This study reports efficient rejection of four typical ionic divalent heavy metals of interest ( i.e. Cd 2+ , Pb 2+ , Cu 2+ , Zn 2+ ) using forward osmosis (FO) by our recently developed nanoporous thin-film inorganic (TFI) membrane fabricated through tetraethylorthosilicate-driven sol-gel process. Upon lab-scale FO cell with feed solution containing heavy metal electrolytes (pH 4.5 ± 0.5) and NaCl serving as draw solution, the TFI membrane yields a high water flux of 69.0 L m −2 h −1 driven by 2.0 mol L −1 -NaCl draw solution. Meanwhile, effective rejection of heavy metal ions was achieved, with an average efficiency of 94% at feed concentration of 200 mg L −1 . Since the membrane is able to reject heavy metals whose hydrated ion diameters are smaller than the membrane pore size, the charge-interaction rather than size exclusion should be responsible for heavy metal rejection. Based on classical Debye-Hückel theory and Gouy-Chapman model, we demonstrate a particular significance of double layer overlap within membrane pore induced by electrostatic interaction between heavy metal ions and silica-made pore walls. As such, the selectivity of TFI membrane depends essentially on the co-function of membrane pore size, surface potential of membrane pore wall as well as Debye length. This study not only confirms the feasibility of the TFI membrane in treating acidic heavy metal-containing wastewater without pH adjustment, but also suggests a simple theoretical scheme to better understand and design charged membrane with expected selectivity for FO applications. [ABSTRACT FROM AUTHOR]

To address the challenges for the common single-mesh oil/water separation, prewetting-induced simultaneous separation methodology with the same material is developed and achieved by a self-fabricated superamphiphilic TiO 2 -coated stainless steel mesh with switchable transportation manners of oil and water based on its superhydrophobicity under oil and strong oleophobicity under water. Furthermore, the mesh is highly recyclable in its separation efficiency (more than 99.9%), flux and self-cleaning property, and tends to be a promising material for controllable oil/water separation. [ABSTRACT FROM AUTHOR]

Photocatalysis has been gaining a growing popularity in water treatment, and their engineered applications inspire the development of effective photocatalyst materials. To develop photocatalyst that is effective for degradation of organic pollutants, we fabricate a novel direct solid Z-scheme BiPO 4 -Bi 2 O 2 (OH)(NO 3 ) (BPO-BHN) heterojunction structured hybrid. The results demonstrate an enhanced photocatalytic activity of BPO-BHN to produce OH radicals, according to diffuse reflectance spectroscopy (DRS), electron spin-resonance resonance (ESR), photoelectrochemical measurements, and theoretical calculation results. The BPO-BHN is shown to greatly promote the degradation of 2,4-dichlorophenol (2,4-DCP) under ultraviolet light. On the basis of pseudo-first-order kinetics, the apparent degradation rate constant ( k app ) of 0.050 min −1 obtained for BPO-BHN is approximately 3.33 and 12.5 times of that for individual BPO ( k app = 0.015 min −1 ) and BHN ( k app = 0.004 min −1 ), respectively. This suggests a virtually synergistic photocatalysis of BPO and BHN when they form a direct solid Z-scheme heterojunction structure, which is favorable for improving UV-light harvesting, hole/electron separation and oxidizing capability. In particular, as a novel non-linear optical (NLO) material, the BHN plays a significant role in the formation of Z-scheme structure for its unique ability of capturing photo-electrons from BPO by high-potential C + face in valence band. This study provides a proof-of-concept strategy to develop more effective photocatalysts for degradation of organic pollutants in water. [ABSTRACT FROM AUTHOR]

The present study reports the wireless electrocoagulation (WEC) based on bipolar electrochemistry where the iron sheets were used as sacrificial bipolar electrodes (BPEs) and two graphite plates served as driving electrodes. Driven by the interfacial potential difference induced by electric field in solution, the iron dissolution started at the anodic pole, achieving the generation of iron coagulant and thus turbidity removal. The total iron concentration produced was found to be more dependent on the geometrical configuration of BPE rather than electrochemical parameters. That is, placing the BPE with the length in parallel to electric field could generate iron concentration of 84.6% higher than that when placed vertically. Besides, increasing the number of BPE from one to three led to the increase in coagulant production by 2.1 times. Moreover, to maximize the voltage drop and minimize the material used, the BPE was designed into different geometrical shapes. The “H-shaped” BPE could achieve almost the same iron concentration as the unmodified BPE even the relative cathode/anode surface area was as low as 0.36. This accounted for efficient coagulant production by saving as great as 40% of the electrode material and cost. The wireless operation can not only solve the problems caused by electrode connection, but also allow arbitrary number of sacrificial BPEs working simultaneously in a very simple setup. In addition, the WEC performance can be easily controlled by the geometrical configuration of BPE. All these factors will be expected to make the electrocoagulation process much easier, more economical and more reliable in water treatment. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) can generate electricity based on oxidation of organic compounds by exoelectogens, giving rise to a promising potential for recovering electrical energy from organic wastewater. The structure and property of anode materials have inherent impact to extracellular electron transfer (EET), an interfacial process that greatly limits bioelectricity production of MFC. Herein, a three dimensional (3D) macroporous nitrogen-enriched graphitic carbon (NGC) scaffold is fabricated from commercially available melamine foam using facile pyrolysis method. The NGC electrode is demonstrated to promote EET efficiently, achieving a power density of 750 mW m−2 based on pure cultured Shewanella oneidensis MR-1 in acetate-feeding MFC. The unique 3D open-cell structure not only offers habitats for colonization of electroactive biofilm up to a maximal density but also provides macroporous architecture for internal mass transfer without concern of bio-blocking and bio-fouling. Additionally, nitrogen incorporation also plays a significant role in enhancing EET, where pyrrolic nitrogen is much more active than graphitic and pyridinic nitrogen as indicated by density functional theory calculation. This work provides a proof-of-concept demonstration of a high-efficiency, cost-effective, easily scaling-up, and environmentally friendly anode material of bioelectrochemical systems for electricity generation, hydrogen production, and pollutant degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A coexistence system with 9–11% flocs was obtained. • The flocs/granules coexistence system exhibited excellent nutrient removal. • Azoarcus and Thauera were enriched in flocs, while GAO was abundant in granules. • Granules and flocs in coexistence system behaved differently on protein level. • GAO and Thauera were the main contributors to the DEPs between granules and flocs. In aerobic granular sludge (AGS) system, flocs typically coexist with granules. The inherent differences between flocs and granules can result in their different behaviors in the same reactor. In this study, a flocs/granules co-existence system was investigated and differences between the flocs and granules in co-existence system were compared on proteomic level, providing an in-depth insight into co-existence of flocs and granules. Results showed that the co-existence system obtained under 4.5 kg COD m−3 d-1 exhibited excellent nutrient removal (COD: 96–97 %, TN: 98–99 %) with approximately 9–11 % flocs. A comparison of flocs and granules in the co-existence system showed different functional bacteria in flocs and granules. The dominant bacteria in granules was Candidatus_Competibacter , while Azoarcus and Thauera were enriched in flocs. Furthermore, proteomic analysis suggested that the metabolic pathways associated with glycogen synthesis and denitrification were more active in granules than that in flocs, while the differentially expressed proteins (DEPs) related to aromatic compounds and xenobiotics metabolism in flocs were more abundant than that in granules. Species annotation revealed that the DEPs between granules and flocs were mainly contributed by Candidatus_Competibacter and Thauera. The in-depth insight into co-existence of flocs and granules provides important reference for the design, optimization and operation of AGS technology in further applications. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation (EO) processes have been gaining a growing popularity in wastewater treatment. Their engineered applications inspire the search for conductive, stable, inexpensive, and sustainable electrode materials. Magnéli-phase titanium oxides have unique crystal and electron structure, which result in good electrical conductivity approaching that of metal and excellent corrosion resistance close to that of ceramics. We fabricated a monolithic porous Magnéli-phase Ti 4 O 7 electrode for EO of refractory industrial dyeing and finishing wastewater (DFWW). The results demonstrated that the electrochemically active area of porous Ti 4 O 7 electrode was 2–3 orders of magnitude higher than the apparent surface area of bulk electrode. The Ti 4 O 7 electrode achieved efficient and stable abatement of recalcitrant organic pollutants on site without any extra addition of chemicals. The soluble chemical oxygen demand (COD) and dissolved organic carbon (DOC) were removed by 66.5% and 46.7%, respectively, at current density of 8 mA cm −2 after 2 h reaction. The bioavailability of treated wastewater was improved substantially, indicated by one order of magnitude increase in BOD 5 /COD. The Ti 4 O 7 electrode had good long-term stability, with its maximum COD removal declined only slightly (<8%) at current density of 20 mA cm −2 during a 50-cycle operation. The organic pollutants appear most likely to be oxidized by electrochemically generated active species like physisorbed OH radical and aqueous ClO − species under mass transfer control condition. The current study provides important insights for achieving efficient and sustainable electrochemical wastewater treatment using the novel porous Ti 4 O 7 electrode material. [ABSTRACT FROM AUTHOR]

[Display omitted] • OLR shock destabilized AGS system, while it reached a new stability eventually. • AGS could activate protection mechanisms to resist OLR shock and recover stability. • Amino acid, aminoacyl-tRNA and UDPG synthesis were up-regulated under OLR shock. • Glycogen synthesis and denitrification were up-regulated under long-term OLR shock. • Abundant GAO contributed to the enhanced glycogen synthesis and denitrification. In this work, the response of aerobic granular sludge (AGS) to organic loading rate (OLR) shock was investigated from proteomic level for the first time. Results showed that OLR shock destabilized AGS system in terms of sludge properties, nutrient removal and microbial community, while they reached a new stability eventually. The AGS system exhibited larger-size granules (4 mm), higher biomass retention (6.9 g/L), enhanced nitrogen removal (97%-99%) and abundant Candidatus_Competibacter (30.7%) under OLR shock. Proteomic analysis demonstrated that AGS system responded to OLR shock by activating protection mechanism through up-regulating numerous metabolic pathways related to amino acid synthesis, aminoacyl-tRNA biosynthesis and gluconeogenesis. With the extension of OLR-shocking tests, AGS up-regulated metabolic pathways associated with glycogen synthesis and denitrification, which were mainly contributed by Candidatus_Competibacter based on species annotation analysis. This study offers an in-depth mechanistic insight into response of AGS to OLR shock and relevant regulation mechanisms, which will provide fundamental information and important implications for practically relevant cases. [ABSTRACT FROM AUTHOR]

Defect engineering is an effective way to unveil relationship within structures and catalytic activities of transition metal oxides. Herein, a novel strategy has been developed for in situ generation and controlling oxygen vacancy (Ov) levels in a host lattice by varying oxygen pressure during calcination of zeolitic imidazolate framework-67 (ZIF-67) membranes. The as-prepared NFZ-5 membrane with the largest Ov content (δ, 0.912) gave the highest 1O 2 production (98.3%) and PMS activated BPA degradation kinetics (k = 0.11 min−1). Advanced characterization and density functional theory (DFT) calculations have revealed the pivotal role of Ov in modifying surface chemistry of the catalytic membrane via enhancing the number of Lewis acid sites. These Lewis acid sites have facilitated the chemisorption of peroxymonosulfate (PMS) onto membrane, and the resulting reactive intermediate complexes have altered the electron transfer direction between PMS and the catalyst. [Display omitted] • A novel strategy was developed to fine-tune the Ov level of ZIF-67 membrane. • NFZ-5 showed the highest 1O 2 yield and the best BPA degradation kinetics. • Ov alters the surface chemistry of catalytic membrane by increasing Lewis acid sites. • A flow-through design outperforms conventional batch electrochemistry. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) can generate electricity from organic substances based on anodic electrochemically active microorganisms and cathodic oxygen reduction reaction (ORR), thus exhibiting promising potential for harvesting electric energy from organic wastewater. The ORR performance is crucial to both power production efficiency and overall cost of MFC. A new type of metal-organic-framework-derived electrocatalysts containing cobalt and nitrogen-doped carbon (CoNC) is developed, which is effective to enhance activity, selectivity, and stability toward four-electron ORR in pH-neutral electrolyte. When glucose is used as the substrate, the maximum power density of 1665 mW m−2 is achieved for the optimized CoNC pyrolyzed at 900 °C, which is 39.8% higher than that of 1191 mW m−2 for commercial Pt/C catalyst in the single-chamber MFC. The improved performance of CoNC catalyst can be attributed to large surface area, microporous nature, and the involvement of nitrogen-coordinated cobalt species. These properties enable the efficient ORR by increasing the active sites and enhancing mass transfer of oxygen and protons at 'water-flooding' three-phase boundary where ORR occurs. This work provides a proof-of-concept demonstration of a noble-metal-free high-efficiency and cost-effective ORR electrocatalyst for effective recovery of electricity from biomass materials and organic wastewater in MFC. [ABSTRACT FROM AUTHOR]

Biofilms from anode heterotrophic bacteria are inevitably formed over cathodic catalytic sites, limiting the performances of single-chamber microbial fuel cells (MFCs). Graphitic carbon (GC) – based nano silver/iron oxide (AgNPs/Fe 3 O 4 /GC) composites are prepared from waste pomelo skin and used as antibacterial oxygen reduction catalysts for MFCs. AgNPs and Fe 3 O 4 are introduced in situ into the composites by one-step carbothermal reduction, enhancing their conductivity and catalytic activity. To investigate the effects of Fe species on the antibacterial and catalytic properties, AgNPs/Fe 3 O 4 /GC is washed with sulfuric acid (1 mol L −1 ) for 0.5 h, 1 h, and 5 h and marked as AgNPs/Fe 3 O 4 /GC-x (x = 0.5 h, 1 h and 5 h, respectively). A maximum power density of 1712 ± 35 mW m −2 is obtained by AgNPs/Fe 3 O 4 /GC-1 h, which declines by 4.12% after 17 cycles. Under catalysis of all AgNP-containing catalysts, oxygen reduction reaction (ORR) proceeds via the 4e − pathway, and no toxic effects to anode microorganisms result from inhibiting the cathodic biofilm overgrowth. With the exception of AgNPs/Fe 3 O 4 /GC-5 h, the AgNPs-containing composites exhibit remarkable power output and coulombic efficiency through lowering proton transfer resistance and air-cathode biofouling. This study provides a perspective for the practical application of MFCs using these efficient antibacterial ORR catalysts. [ABSTRACT FROM AUTHOR]

Electrocatalytic peroxymonosulfate (PMS) activation is a promising advanced oxidation process for the degradation of micropollutants. Herein, we developed an electroactive carbon nanotube (CNT) filter functionalized with Fe 3 O 4 -MnO 2 hybrid (Fe 3 O 4 -MnO 2 /CNT) to activate PMS towards ultrafast degradation of sulfamethoxazole (SMX). SMX was completely degraded via a single-pass through the nanohybrid filter (τ < 2 s). The ultrafast degradation kinetics were maintained across a wide pH range (from 3.0 to 8.0), in complicated matrices (e.g. , tap water, lake water, WWTP effluent and pharmaceutical wastewater), and for the degradation of various persistent micropollutants. Compared with a conventional batch reactor, the flow-through operation provides an 9.2-fold higher SMX degradation kinetics by virtue of the convection-enhanced mass transport (1.47 vs. 0.16 min−1). The efficient redox cycle of Fe2+/Fe3+ and Mn2+/Mn4+ facilitate the PMS activation to generate SO 4 •– under electric field. Meanwhile, the ketonic groups on the CNT provide active sites for the generation of 1O 2. Both experimental and theoretical results revealed the superior activity of nanohybrid filter associated with the synergistic effects among Fe, Mn, CNT and electric field. Therefore, the electrocatalytic filter based PMS activation system provides a green strategy for the remediation of micropollutants in a sustainable manner. [Display omitted] • An electrocatalytic filtration system was developed toward PMS activation. • Ultrafast degradation of micropollutants can be achieved within 2 s. • Radical and nonradical pathways collaboratively contributed to organic oxidation. • The efficacy was originated from the synergism of Mn, Fe, CNT and electric field. [ABSTRACT FROM AUTHOR]

[Display omitted] • A H*-mediated electrocatalytic filtration system was developed for PMS activation. • Ultra-fast degradation of selected emerging contaminants can be achieved within 2 sec. • Both radical and non-radical pathways synergistically contributed to organic degradation. • H*-transfer pathway was thermodynamically favorable for PMS activation. The peroxymonosulfate (PMS) activation by atomic H* is thermodynamically favorable. Herein, we rationally designed a novel H*-mediated electrocatalytic filtration system for PMS activation system to achieve highly efficient degradation of emerging organic contaminants. The key to this system was an electroactive carbon nanotube (CNT) filter functionalized with nanoscale Pd. A complete degradation of 0.04 mM sulfamethoxazole could be achieved just by passing through the filter once (τ < 2 sec). The experimental analysis and DFT studies verified that H* was the key component triggering the generation of reactive oxygen species by PMS activation. The flow-through configuration significantly outperformed the conventional batch reactor due to the enhanced mass transport by convection. The observed efficacy could be maintained in complex matrices as well as for the degrading of diverse persistent contaminants. The mechanistic studies suggested that both radical and non-radical pathways contributed collectively to the ultrafast degradation of organic contaminants. [ABSTRACT FROM AUTHOR]

In this study, mycelial pellets (MPs) were employed as efficient and sustainable bio-carriers to alleviate membrane fouling in membrane bioreactor (MBR). The comparative study was performed in lab-scale MBR in the absence and presence of MPs addition under continuous operation for 80 days. The results demonstrated efficient removal of chemical oxygen demand (COD) and ammonia nitrogen (NH 4 +-N) for both systems, while MPs addition led to lower rate at which transmembrane-pressure was increased, lower filtration resistance, thinner bio-cakes and fewer contents of extracellular polymeric substances (EPS) and soluble microbial products (SMP) in bio-cakes of membrane surface. Adding MPs into MBR could enhance biomass retention and EPS content in suspended liquid, thus accelerating the granulation of activated sludge, which should be responsible for mitigation of membrane fouling. According to the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the total surface free energy between membrane and foulants was always attractive, but total interfacial interaction especially acid-based (AB) interaction in the presence of MPs was weaker than that in the absence, confirming lower adhesion force induced by MPs. Furthermore, high throughput sequencing analysis of bio-cakes illustrated that a smaller relative abundance of EPS producer including the classes Gammaproteobacteria , Alphaproteobacteria and Actinobacteria , and a higher abundance of SMP decomposer including the class Chloroflexia were observed. The relevant mechanisms were underlined schematically to explain the function of MPs in mitigating membrane fouling process, which could be attributed to formation of biofilm with MPs serving as bio-carriers followed by promoted sludge granulation. This study provides a proof-in-concept demonstration of using MPs as bio-carriers to mitigate membrane fouling, making wastewater treatment by MBR more efficient, more reliable and more sustainable. [Display omitted] •MPs were employed as efficient bio-carriers to alleviate membrane fouling. •The presence of MPs promoted sludge granulation. •MPs addition reduced the deposition of flocs sludge on membrane surface. •MPs addition led to lower filtration resistance and fewer foulants. [ABSTRACT FROM AUTHOR]

This study reports the development of complete solar-driven dual-photoelectrode fuel cell (PFC) based on WO 3 photoanode and Cu 2 O photocathode with peroxymonosulfate (PMS) serving as cathodic electron acceptor. As indicated by photoelectrochemical measurements, the PMS was able to improve thermodynamic properties of photocathode, achieving an increased open circuit potential from 0.42 V to 0.65 V vs standard hydrogen electrode (SHE). Under simulated sunlight irradiation (~100 mW cm−2), the maximum power density of 0.12 mW cm−2 could be obtained at current density of 0.34 mA cm−2, which was 8.57 times of that produced by PFC without PMS (0.014 mW cm−2). Correspondingly, adding PMS (1.0 mM) increased overall removal efficiency of 4-chlorophenol (4-CP) from 39.8% to 96.8%, accounting for the first-order kinetic constant (k =0.056 min−1) being 6.67 times of that in the absence of PMS (k =0.0084 min−1). Radical quenching and electron spin-resonance (ESR) results suggested the contribution of free radicals (•OH and SO 4 •-) and non-radical pathway associated with direct activation of PMS by Cu 2 O photocathode. Fourier transformed infrared (FTIR) analysis confirmed the strong non-radical interaction between Cu 2 O photocathode and PMS, resulting in 4-CP removal via activation of PMS by surface complex on Cu 2 O. The proof-in-concept complete solar-driven dual-photoelectrode fuel cell may offer an effective manner to realize water purification and power generation, making wastewater treatment more economical and more sustainable. [Display omitted] • A complete solar-driven dual-photoelectrode fuel cell is developed. • The peroxymonosulfate (PMS) improves thermodynamic properties of Cu 2 O photocathode. • Radical (OH• and SO 4 •-) and non-radical (surface complexs) pathway are responsible for 4-chlorophenol (4-CP) removal. [ABSTRACT FROM AUTHOR]

Abstract: Sustainable electricity was generated from glucose in up-flow air-cathode microbial fuel cells (MFCs) with carbon cloth cathode and carbon granular anode. Plastic sieves rather than membrane were used to separate the anode and cathode. Based on 1g/l glucose as substrate, a maximum volumetric power density of 25±4W/m3 (89A/m3) was obtained for the MFC with a sieve area of 30cm2 and 49±3W/m3 (215A/m3) for the MFC with a sieve area of 60cm2. The increased power density with larger sieve area was mainly due to the decrease of internal resistance according to the electrochemistry impedance spectroscopy analysis. Increasing the sieve area from 30cm2 to 60cm2 resulted in a decrease of overall internal resistance from 41Ω to 27.5Ω and a decrease of ohmic resistance from 24.3Ω to 14Ω. While increasing operational recirculation ratio (RR) decreased internal resistance and increased power output at low substrate concentration, the effect of RR on cell performance was negligible at higher substrate concentration. [Copyright &y& Elsevier]

Abstract: An air-cathode microbial fuel cell (MFC) is an efficient and sustainable MFC configuration for recovering electrical energy from organic substances. In this paper, we developed a graphite-granule anode, tubular air-cathode MFC (GTMFC) capable of continuous electricity generation from glucose-based substrates. This GTMFC produced a maximum volumetric power of 50.2Wm−3 at current density of 216Am−3 (R EX =22Ω). Electrochemistry impedance spectroscopy (EIS) measurements demonstrated an overall internal resistance of 27Ω, consisting of ohmic resistance of R ohm =13.8Ω (51.1%), a charge-transfer resistance of R c =6.1Ω (22.6%) and a diffusion resistance of R d =7.2Ω (26.3%). Power generation with respect to initial chemical oxygen demand (COD) concentration was described well by an exponential saturation model. Recirculation was to found to have a significant effect on electrochemical performance at low COD concentrations, while such effect was absent at high COD concentrations. This study suggests a feasible and simple method to reduce internal resistance and improve power generation of sustainable air-cathode MFCs. [Copyright &y& Elsevier]

Abstract: The microbial fuel cell (MFC) was proved to be a novel bioprocess capable of recovering electrical energy from organic matter. In this study, we report that by using permanganate as the cathodic electron acceptor for a MFC we were actually able to recover much more electrical power than using other existing types of electron acceptors, e.g. using permanganate as the cathodic electron acceptor for a two-chamber MFC generated a maximum power density of 115.60mWm−2 which was, respectively, 4.5- and 11.3-fold higher than that produced by using hexacynoferrate (25.62mWm−2) and oxygen (10.2mWm−2) as the cathodic electron acceptor. This could be attributed to the higher open circuit potential (OCP) provided by permanganate in the MFC. Besides, pH, unlike permanganate concentration, was further found to have a major impact on the OCP and the cathode potential. SEM and XPS analysis demonstrated that manganese dioxide (MnO2) was in fact the main reduced product of the permanganate at pH 3.6. Moreover, as compared to a two-chamber MFC, a bushing MFC using permanganate as the cathodic electron acceptor achieved an unprecedented maximum power-output of 3986.72mWm−2. This study for the first time showed that permanganate could be used as an effective cathodic electron acceptor for a MFC. [Copyright &y& Elsevier]

[Display omitted] • Fungal pellets were applied to enhance long-term stability of AGS. • FPs enhanced structural and functional stability of granules simultaneously. • FPs inhibited filamentous overgrowth. • FPs dosage enriched functional bacteria involved in nutrients removal. The effects of fungal pellets (FPs) dosage on both structural and functional stability of aerobic granular sludge (AGS) were investigated during 200-day operation. Results showed that the AGS induced by low (a dry mass ratio of FPs to seed sludge, 30%) and high FPs dosage (60%) exhibited good morphology integrity during the entire phase of operation, while the filamentous overgrowth and AGS breakup were observed in the control reactor (0% FPs). Moreover, the granules developed at high FPs dosage demonstrated excellent nutrients removal (COD: 93%; NH4+-N: 100%; TN: 77%) and stable bioactivity with a maximum specific oxygen uptake rate (SOUR) of 52.6 ± 2.6 mg O 2 /(gVSS·h), a value being 12.2% and 26.7% higher than that of 30% and 0% dosage. The microbial community analysis revealed 60% FPs dosage enriched various functional bacteria involved in nutrients removal. This study suggests a sustainable strategy for improving structural and functional stability of AGS. [ABSTRACT FROM AUTHOR]

• TiO 2 -coated Co 3 O 4 @NGC derived from ZIF-67 is used as ORR catalyst for the first time. • Co 3 O 4 @NGC@MP-TiO 2 -0.3 shows high ORR activity/stability in 0.1 M KOH or 0.5 M H 2 SO 4. • Synergy between Co Td 2+ and Ti3+ can greatly enhance charge transfer and ORR kinetics. • Acid-pickling of CoO x @NGC improves Co 3 O 4 @NGC stability to smooth ORR in acid media. • TiO 2 shell protect Co 3 O 4 core from corrosion to make its stability higher than Pt/C. The sluggish kinetics of oxygen reduction reaction (ORR), especially in acid media, seriously restrains the commercialization of direct methanol fuel cells. Herein, we synthesize a hierarchical Co 3 O 4 @N-doped partly-graphitized carbon wrapped by Ti3+-self-doped TiO 2 nanoparticles with multiple crystal-phases (anatase and rutile TiO 2) as catalysts (Co 3 O 4 @NGC@MP-TiO 2) for ORR in alkaline/acid media using ZIF-67 as a precursor. Co 3 O 4 @NGC@MP-TiO 2 -0.3 (tetrabutyl titanate of 0.3 mL) exhibits the same peak potential (E peak of 0.83 V, vs. RHE) as Pt/C in 0.1 M KOH and the comparable E peak (0.69 V) to Pt/C (0.7 V) in 0.5 M H 2 SO 4. Synergistic effects between tetrahedral Co2+ (Co 3 O 4) and Ti3+ (MP-TiO 2) chiefly contribute to the high ORR activity. ORR stabilities of Co 3 O 4 @NGC@MP-TiO 2 -0.3 are higher than those of Pt/C in alkaline/acid media, attributing to that NGC@MP-TiO 2 shell can protect active sites (tetrahedral Co2+ and N species) from corrosion and deactivation. Moreover, the dissociated adsorption of O 2 on Ti3+ may facilitate the O 2 protonation (Ti4+–OOH ads −) to accelerate electron-transfer process and ORR kinetics in acid electrolyte, while acid-pickling of CoO x @NGC improves the stability of Co 3 O 4 @NGC to further smooth ORR process. This study provides a promising strategy for the design of highly-active and stable ORR catalysts in both alkaline and acid electrolytes. [ABSTRACT FROM AUTHOR]

Design of multi-hierarchical hybrid catalyst with high activity (bifunctional active-sites) is urgently needed by oxygen evolution/reduction reactions (OER/ORR). This study reports a feasible method for anchoring the copper oxide nanoparticles on the surface of Zeolitic Imidazolate Framework-67 derived cobalt oxide@nitrogen-doped graphitized carbon (Co 3 O 4 @NGC@CuO). For OER, Co 3 O 4 @NGC@CuO-0.6 (mass ratio of CuCl 2 ·2H 2 O to Co 3 O 4 @NGC = 0.6) requires only 210 mV overpotential to achieve a current density of 10 mA cm−2 and a faraday efficiency of 93.5%. Owing to the synergies between CuO (Cu2+) shells and Co 3 O 4 (Co2+/Co3+) cores, Cu2+ active sites can moderate the adsorption of oxygen-containing substances and balance the Co2+/Co3+ ratio. Tetrahedral Co2+ (Co2+ Td) can be served as the active sites to induce the μ-OOH moieties (Octahedral Co3+, CoOOH) to enhance OER activity and stability. For ORR, Co 3 O 4 @NGC@CuO-0.6 has a half-wave potential of 0.865 V, comparable to that of commercial Pt/C (0.868 V). CuO with Cu2+/Cu+ can increase the O 2 adsorption sites, while the active Co Td 2+ sites can boost the breakage of O–O bonds to produce OH− via a 4e− ORR pathway. The bifunctional activity [ΔE = E 10 (OER)-E 1/2 (ORR)] of Co 3 O 4 @NGC@CuO-0.6 is only 0.58 V, confirming excellent ORR/OER activities. This study provides a promising strategy for constructing versatile active sites on catalysts. Image 1 • ZIF-derived Co 3 O 4 @NGC@CuO is synthesized to enhance OER/ORR for the first time. • Hierarchical structure of Co 3 O 4 @NGC offers enough binding sites for anchoring CuO. • Synergisms of Co 3 O 4 @CuO heterojunction and N-species realize strong OER/ORR activity. • CuO thin layer protects catalytic centers on Co 3 O 4 core to obtain high durability. • Both OER and ORR occurred on Co 3 O 4 @NGC@CuO favor the 4e− pathway in alkaline media. [ABSTRACT FROM AUTHOR]

• Increased permeate flux and mass transfer of REM via O 2 removal by ultrasound. • Oxidation rate of 4-CP in EO-US was 216% higher than that in EO. • The most efficient degradation pathway of 4-CP was DET followed by OH oxidation. • Stability of TiSO-REM was improved by ultrasound via electrode fouling mitigation. Reactive electrochemical membrane (REM) allows electrochemical oxidation (EO) water purification under flow-through operation, which improves mass transfer on the anode surface significantly. However, O 2 evolution reaction (OER) may cause oxygen bubbles to be trapped in small-sized confined flow channels, and thus degrade long-term filterability and treatability of REM. In this study, ultrasound (ultrasonic vibrator, 28 kHz, 180 W) was applied to EO system (i. e. sonoelectrochemistry) containing titanium suboxide-REM (TiSO-REM) anode for enhanced oxidation of 4-chlorophenol (4-CP) target pollutant. Both experimental and modeling results demonstrated that ultrasound could mitigate the retention of O 2 bubbles in the porous structures by destructing large-size bubbles, thus not only increasing permeate flux but also promoting local mass transfer. Meanwhile, oxidation rate of 4-CP for EO with ultrasound (EO-US, 0.0932 min−1) was 216% higher than that for EO without ultrasound (0.0258 min−1), due to enhanced mass transfer and OH production under the cavitation effect of ultrasound. Density functional theory (DFT) calculations confirmed the most efficient pathway of 4-CP removal to be direct electron transfer of 4-CP to form [4-CP] +, followed by subsequent oxidation mediated by OH produced from anodic water oxidation on TiSO-REM anode. Last, the stability of TiSO-REM could be improved considerably by application of ultrasound, due to alleviation of electrode deactivation and fouling, indicated by cyclic test, scan electron microscopy (SEM) observation and Fourier transform infrared spectroscopy (FT-IR) characterization. This study provides a proof-of-concept demonstration of ultrasound for enhanced EO of recalcitrant organic pollutants by REM anode, making decentralized wastewater treatment more efficient and more reliable. [ABSTRACT FROM AUTHOR]

Herein, individual p -block bismuth (Bi) atoms are dispersed onto N-doped Ti 3 C 2 T x MXene (BiN 3 /MXene) to enhance the 3 e − oxygen reduction reaction (ORR), for the electrosynthesis of hydroxyl radicals (HO•) via the activation of molecular oxygen (O 2). Theoretical calculations and experiments reveal that the p -orbitals of Bi atoms can readily hybridize with the p- orbitals of O, which enables the transfer of charges, creates sufficient strength of adsorption for oxygen intermediates, lowers the activation energy, and modulates the rate-limiting reaction. The optimized generation of HO• is up to 26.7 μmol/(L·h·cm2) without additional chemical reagents, facilitating efficient removal of micropollutants from complex water matrices. Specifically, the rate constant (k obs) for sulfamethoxazole degradation achieves 1.027 min−1, outperforming the reported processes for micropollutants removal. This work illuminates the atomic-level construction of a p -block BiN 3 /MXene electrocatalytic membrane to efficiently perform the 3 e − ORR and highlights the substantial potential for wastewater decontamination. [Display omitted] • p -Block single Bi atoms can be anchored onto MXene via coordination engineering. • The BiN 3 /MXene membrane enabled selective O 2 electroreduction to HO• via 3 e − pathway. • A complete and rapid removal of SMX was achieved with minor energy requirements. • Underlying mechanism was unveiled based on experimental evidences and theoretical calculations. [ABSTRACT FROM AUTHOR]

• (WC)/W 24 O 68 /NC Z8 supports are used as Pt promoters for MOR/ORR for the first time. • NC Z8 promotes carburization of W atoms in W 24 O 68 to form WC/W 24 O 68 heterojunctions. • Reversible reaction between W 24 O 68 and formed H y (WO) 3 (0 < y < 1) enhances MOR activity. • WC/W 24 O 68 heterojunctions boost charge transfer at mixed crystal interfaces for ORR. • Synergistic effects among WC/W 24 O 68 , NC Z8 and Pt enhance MOR and ORR performances. To make methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) more efficient, it is essential to explore Pt support (low Pt-loading) with desirable co-catalytic activity. Herein, tungsten carbide/tungsten oxide/zeolitic imidazolate framework-8 (ZIF-8)-derived carbon ((WC)/W 24 O 68 /NC Z8) composites are prepared as Pt-supports/co-catalysts. Heating temperature is controlled to adjust structure and crystalline phases of (WC)/W 24 O 68 /NC Z8. For MOR, mass activity (2492.2 mA mg−1 Pt) of Pt-WC/W 24 O 68 /NC Z8 (850 °C, 5.0 wt.%) is much superior to commercial Pt/C (499.2 mA mg−1 Pt , 10.0 wt.%). NC Z8 -thin-layer facilitates carburization of W atoms (W 24 O 68 to WC) to form WC/W 24 O 68 heterojunctions. Oxygen vacancies on W 24 O 68 fascinate H+ to encourage formation of tungsten bronze compounds (H y WO 3 , (0 < y < 1)), and reversible reaction between W 24 O 68 and H y (WO) 3 (0 < y < 1) contributes to a high MOR activity and CO resistance. Pt-WC/W 24 O 68 /NC Z8 (850 °C) also exhibits a higher ORR activity (4e-) than Pt/C in acidic media. WC/W 24 O 68 heterojunctions accelerate mass and charge transfer at the mixed crystal interfaces for ORR. [ABSTRACT FROM AUTHOR]

• ZIF-derived CoO@NPC@SnO 2 is used as ORR catalyst/MOR co-catalyst for the first time. • SnO 2 and NPC shells can prevent the CoO cores from corrosion and aggregation. • Synergies among CoO (Co2+), N species and oxygen vacancies can enhance ORR kinetics. • Interactions between Pt and SnO 2 facilitate charge transfer to improve MOR activity. • The formed Metal-OH ads species can remove CO ads during MOR to enhance the durability. Fabrication of efficient catalyst/co-catalyst for enhancing methanol oxidation and oxygen reduction reactions (MOR/ORR) is the key to make direct methanol fuel cells more economical. Here, hierarchical CoO@nitrogen-doped porous carbon@SnO 2 (CoO@NPC@SnO 2) polyhedrons are prepared as active catalysts for ORR and Pt supports/co-catalysts for MOR using zeolitic imidazolate frameworks-67 (ZIF-67). For ORR, CoO@NPC@SnO 2 -1 (Co@NPC-to-SnCl 2 ·2H 2 O mass ratio of 1: 1) exhibits a more positive peak potential (0.82 V vs. RHE) than that of commercial Pt/C (10 wt.%). Outer SnO 2 shells can prevent CoO cores (active tetrahedral Co2+) from corrosion during ORR. For MOR, Pt-CoO@NPC@SnO 2 -1 (5 wt.%) shows a much higher mass activity (1518 mA mg Pt −1) than that of Pt/C (496.8 mA mg Pt −1). High CO tolerance of Pt-CoO@NPC@SnO 2 -1 is attributed to strong metal (Pt)-metal oxides (SnO 2) interactions, which facilitate adsorption of OH− on SnO 2 to remove CO ads. Therefore, this study provides a strategy to enhance ORR/MOR performance by using hierarchically-structured catalysts/co-catalysts from ZIF templates. [ABSTRACT FROM AUTHOR]

Due to high maneuverability as well as hardware limitations of Unmanned Aerial Vehicle (UAV) platforms, tracking targets in UAV views often encounter challenges such as low resolution, fast motion, and background interference, which make it difficult to strike a compatibility between performance and efficiency. Based on the Siamese network framework, this paper proposes a novel UAV tracking algorithm, SiamHSFT, aiming to achieve a balance between tracking robustness and real-time computation. Firstly, by combining CBAM attention and downward information interaction in the feature enhancement module, the provided method merges high-level and low-level feature maps to prevent the loss of information when dealing with small targets. Secondly, it focuses on both long and short spatial intervals within the affinity in the interlaced sparse attention module, thereby enhancing the utilization of global context and prioritizing crucial information in feature extraction. Lastly, the Transformer's encoder is optimized with a modulation enhancement layer, which integrates triplet attention to enhance inter-layer dependencies and improve target discrimination. Experimental results demonstrate SiamHSFT's excellent performance across diverse datasets, including UAV123, UAV20L, UAV123@10fps, and DTB70. Notably, it performs better in fast motion and dynamic blurring scenarios. Meanwhile, it maintains an average tracking speed of 126.7 fps across all datasets, meeting real-time tracking requirements. [ABSTRACT FROM AUTHOR]

• Auricularia is used to prepare Co 8 FeS 8 /NSC via thorough coordination of precursors. • MFC with Co 8 FeS 8 /NSC (900 °C) cathode has higher performance and stability than Pt/C. • Co2+ and Fe2+ in Co 8 FeS 8 provide more active sites to achieve rapid kinetics for ORR. • Co 8 FeS 8 with multiple atoms boosts side-on oxygen adsorption to enhance ORR activity. • Porous structure with N-species has abundant available channels for mass transfer. The main issues regarding the practical application of microbial fuel cells (MFCs) are the poor activity and tolerance of oxygen reduction reaction (ORR) catalysts in wastewater. In this study, Auricularia chelated with Co, Fe and S ions is used as a nitrogen (N)-enriched carbon source to prepare N-doped bimetallic sulfide (Co 8 FeS 8)-embedded carbon spheres (Co 8 FeS 8 /NSC) using a hydrothermal method. The effects of various temperatures (800–950 °C) on the structure and catalytic activity of Co 8 FeS 8 /NSC catalysts are investigated. The MFC with a Co 8 FeS 8 /NSC (900 °C) cathode obtained the maximum power density of 1.002 W m−2, which is higher than that of Pt/C (0.88 W m−2). After 1440 h of operation, the power density of the Co 8 FeS 8 /NSC (900 °C) cathode only declined by 5.49%, indicating that the Co 8 FeS 8 activity, charge transfer and O 2 transport were slightly influenced by the attached microbes and poisonous substances in the wastewater. The electrochemical results indicate that Co 8 FeS 8 /NSC (900 °C) mainly proceeds by a 4e− ORR pathway, indicating that Co 8 FeS 8 (Co2+ and Fe2+) wrapped in NSCs (carbon spheres) can trigger synergistic effects to provide more active sites and high electrical conductivity to achieve the rapid kinetics required for the ORR. Moreover, the porous structures of the NSCs (220.97 m2 g−1) with incorporated pyridinic N, pyrrolic N and graphitic N can provide abundant available channels for O 2 and OH− transport to ensure the preferential accessibility of the reactant molecules to active sites. This indicates that Auricularia-derived Co 8 FeS 8 /NSC catalysts have great potential as alternatives for precious metal-based catalysts in neutral electrolyte MFCs. [ABSTRACT FROM AUTHOR]

Protecting active species from aggregation and corrosion may be feasible to obtain stable catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, bamboo-shaped N -doped carbon nanotubes (hollow BS-NCNTs as shells) are self-generated to in situ wrap the Co/CoO x schottky junctions (cores) to obtain the Co/CoO x @BS-NCNTs as bifunctional ORR/OER catalysts by using the Co-chelated melamine precursor. For ORR, Co/CoO x @BS-NCNTs (700 °C) exhibits more positive peak (0.822 V vs. RHE) and half-wave (0.842 V vs. RHE) potential than those of commercial Pt/C (10 wt%). Superior ORR activity is mainly attributed to the enriched coordination-unsaturated Co2+ (tetrahedral Co Td 2+) in the CoO x wrapped in the tubular structure of BS-NCNTs featuring high electrical conductivity and active N species. Moreover, the π-π bonds of CNTs are activated by N substitution, which provides a stunning electron capture and transmission capability for enhancing ORR activity. For OER, Co/CoO x @BS-NCNTs (700 °C) obtains a smaller potential (1.590 V vs. RHE) than that of RuO 2 /C at 10 mA cm−2. The outstanding OER activity and durability of Co/CoOx@BS-NCNTs (700 °C) originates from strong interactions between C-skeleton and Co species, and efficient Co3+/Co4+ (Co4+OOH as active sites) transition protected by the externally-grown CNTs. Furthermore, abundant oxygen vacancies on CoO x surface can facilitate the adsorption of OH−/or OER-related intermediates to improve OER activity. Therefore, this study provides a promising strategy to develop NCNTs-wrapped Co species with high catalytic activity and stability for energy conversion. [ABSTRACT FROM AUTHOR]

Abstract Excessive organic emissions measured as chemical oxygen demand (COD) have caused serious regional water pollution i.e. the widespread malodorous black rivers in China. Assessing the optimum treatment strategies is generally a complicated work involving sophisticated trade-offs across regional improvement and global sustainability. Life cycle assessment (LCA) is a promising tool to support such trade-offs, but it appears difficult to comprehensively reflect the direct impact of high-COD wastewater. This is because, the current LCA framework only highlights the effect of nutrients as a representative eutrophication indicator. To address this issue, this study extends the LCA framework by defining a new COD category to characterize the oxygen-depleting processes associated with development of characterization factors and models. By combining water quality model, the modeling scheme is shown capable of converting dynamic effects of COD on the receiving water into the spatially differentiated impact-assessment results. Upon a descriptive case, we also illustrate that the modeling scheme can construct different environmental situations by varying the embedded variables. This enables the refined investigations of the paradigm shift in wastewater treatment, which contributes to the avoidance of "one-size-fits-all" solution identified without considerations of environmental sustainability. Last, we discuss the ways to further refining the modeling scheme to make it applicable in more cases of water pollution. Graphical abstract Unlabelled Image Highlights • Propose a regional modeling scheme for life cycle assessment in wastewater treatment • Characterization of oxygen-depleting process associated with organic transportation in LCA framework • Water quality model is integrated into the defined COD category. • Refined case investigations are available by varying the embedded variables. • Avoidance of "one-size-fits-all" solution is possible via the modeling scheme. [ABSTRACT FROM AUTHOR]

Abstract A Fe-N-C catalyst is supposed to drive commercialization of microbial fuel cells (MFCs) because of its remarkable catalytic performance on oxygen reduction reaction (ORR). However, the catalyst suffers from unclear active site structure and unknown responses of the cathodic microbial community. Here, we prepared a mesoporous core-shell structure catalyst with a nitrogen doped matrix carbon shell, and a Fe 3 O 4 core (Fe 3 O 4 @N-mC) as efficient cathode catalysts for the oxygen reduction reaction (ORR). The resulting hybrid electrocatalyst (Fe 3 O 4 @N-mC) showed higher limiting current density (2.94 mA cm−2), lower H 2 O 2 yield (7.2–12.7%), and a higher electron transfer number (3.74–3.85) for ORR activity than its intermediates, including Fe 3 O 4 , polyaniline (PANI), nitrogen doped carbon (N-C), and magnetic polyaniline composite (Fe 3 O 4 @PANI). In MFC tests, Fe 3 O 4 @N-mC produced a power density of 0.73 W m−2, which was 2.14 times of N-C (0.34 W m−2), 3.84 times of Fe 3 O 4 @PANI (0.19 W m−2), and more than four times of Fe 3 O 4 (4.29, 0.17 W m−2) and PANI (4.87, 0.15 W m−2). Illumina sequencing of 16S rRNA gene amplicons and non-metric multi-dimensional scaling (NMDS) indicated distinct separation of the cathode biofilm bacterial communities between MFCs with different cathodic catalysts. MFCs with the Fe 3 O 4 @N-mC cathode facilitated the enrichment of putative exoelectrogenic Dietzia. Our findings suggest that enhancing ORR performance of Fe 3 O 4 @N-mC in MFCs can be attributed to the co-effects of Fe and N, the core-mesoporous shell structure, and various nitrogen functionalities. Graphical abstract fx1 Highlights • The Fe 3 O 4 core-mesoporous N-doped carbon shell catalyst was synthesized for ORR. • Chemical Fe-N bond and doped-N functionalities resulted in high ORR activity. • Different cathode catalysts led to a shift in the microbial community of MFC. • MFC with Fe 3 O 4 @N-mC cathode facilitates enrichment of electroactive bacteria. [ABSTRACT FROM AUTHOR]

We developed and optimized an electrocatalytic filtration system to catalytically hydrodechlorinate chlorophenolic compounds. A key part of the system was the cathode, which consisted of a filter constructed with electroactive carbon nanotubes (CNTs) functionalized with atomically precise gold nanoclusters (AuNCs). In the functional membrane electrode, the AuNCs attached to the CNTs functioned as a highly effective hydrodechlorination catalyst. Additionally, the ligands of the AuNCs facilitated the binding of the AuNCs with the CNT and protected the Au core from agglomeration. Atomic H* was the primary reactive species in the system, but direct reduction by cathode electrons also contributed to the elimination of 2,4-dichlorophenol (2,4-DCP) by hydrodechlorination. The generated atomic H* was able to break the C–Cl bond to achieve the rapid hydrodechlorination of 2,4-DCP into phenol, with 91.5% 2,4-DCP removal within 120 min. The AuNC catalysts attached to the CNT exceeded the best catalytic activity of larger nanoparticles (e.g., AuNPs), while the flow-through construction performed better than a standard batch reactor due to the convection-enhanced mass transport. The study provides an environmentally friendly strategy for the elimination of pervasive halogenated organic contaminants using a highly efficient, stable and recyclable system for hydrodechlorination that integrates nanofiltration and electrochemistry. [ABSTRACT FROM AUTHOR]

Porous electrodes offer a new opportunity for flow‐through electrochemical water purification, but their irregular porous‐structure makes the local flow pattern and mass transfer performance inhomogeneous, unpredictable, and uncontrollable. In this study, a bio‐inspired design is reported for porous electrode by learning the micro‐scale architectures of the wings of butterfly and owl based on analogy between heterogeneous mass transfer and sound absorption. Results demonstrate that combining gyroid and perforated plate can produce strong periodic vortex and inertial flow in interpenetrating channels even at laminar flow region. This enables homogeneous, predictable and controllable flow patterns and enhanced mass transfer, which can be explained by uniformity analysis and physical field synergy. Based on experimental tests on Cu electrode fabricated by selective laser melting, the composite gyroid electrode generates the limiting current density of 83% higher than random porous‐structured electrode, accounting for nitrate removal as high as 95% by electrochemical denitrification. This study represents a paradigm shift to advance design for porous architectures by learning experiences of hydrodynamic behaviors from nature. In this way, it is feasible to enhance mass transfer by modifying local flow patterns on pore scale, which may have broader implications that extend to other heterogeneous reaction systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co, N co‑doped CNTs with in-situ anchored NiFe alloys are used as an oxygen catalyst. • Well-formed tubular Co-N@CNTs offers enough binding sites for anchoring NiFe alloys. • The Co-N x -C species on Co-N@CNTs can provide effective active sites to stabilize ORR. • In situ formed NiOOH/FeOOH from NiFe alloy are favored as active species for OER. • Synergistic effects between NiFe alloys and Co-N x -C species improve ORR/OER activity. Transition metal alloys have emerged as promising catalysts for oxygen reduction/evolution reactions (ORR/OER) because of their intermetallic synergy and tunable redox properties. However, for alloy nanoparticles, it is quite challenging to suppress the self-aggregation and promote the bifunctional activity. Anchoring alloys in heteroatoms-doped carbon matrix with excellent electro-conductibility is a powerful strategy to form strongly-coupled alloy-carbon nanohybrids. Here, highly-dispersed NiFe alloys are evenly in-situ anchored on the surface of Co, N co-doped carbon nanotubes (NiFe/Co-N@CNTs) via a gravity-guided chemical vapor deposition and self-assembly strategy. Stably-structured NiFe/Co-N@CNTs possesses a tubular skeleton with diameters of 80–100 nm and a hydrophilic surface. For ORR, half-wave potential of NiFe/Co-N@CNTs (0.87 V vs RHE) is higher than that of Pt/C (0.85 V). Strong synergies between NiFe alloys and Co-N x species facilitate the charge transfer on one-dimensional conductive structure to boost the 4e- ORR kinetics. For OER, NiFe/Co-N@CNTs has a lower overpotential (300 mV) than RuO 2 (400 mV) at 10 mA cm−2 due to in-situ formation of highly-active NiOOH/FeOOH species (as indicated by in-situ X-ray diffraction) at the catalytic sites on NiFe alloy. Rechargeable Zn-air battery (ZAB) with NiFe/Co-N@CNTs-based air–cathode exhibits promising open-circuit potential (1.52 V) and charge–discharge cycling stability (350 h). This alloy-carbon integrating strategy is meaningful for promoting dispersion, activity and stability of non-noble metal alloys for oxygen electrocatalysis. [ABSTRACT FROM AUTHOR]

Efficient photo-Fenton removal of antibiotic effluent is a widely followed and significant attempt to deal with the growing environmental pollution. In this study, BiFeO 3 and lanthanum doped BiFeO 3 catalysts were synthesized via one-step hydrothermal method as hydrogen peroxide activator for mineralization of norfloxacin (NOR). Various characterization measurements were used to verify La was successfully doped into the lattice of perovskite and investigated the effect of La doping molar ratio on BiFeO 3 through the characterization of the morphology and physicochemical properties. The degradation experiment and reaction rate constants showed that the La-doped BiFeO 3 particle exhibited superior photo-Fenton catalytic performance to undoped BiFeO 3. Especially, the degradation efficiency of 15% La-doped BiFeO 3 could reach up to 84.94%. And the first order kinetic constant of optimized conditions was 0.01638 min−1, which was about 6.9 times than that of undoped BiFeO 3.The influence of pH, oxidizer content and catalyst dosage in photo-Fenton reaction were investigated detailedly. Besides, the synthetic catalyst possessed favorable stability and reusability with little metal leaching after many cycles of use. Radical scavenger experiments and electron spin resonance tests were carried out to conclude that the ·OH and holes were regarded as the dominate active species in the catalytic process. The narrow band gap and excellent electron transfer efficiency were the key factors for La-doped BiFeO 3 to have high catalytic efficiency in the photo-Fenton system. Current works demonstrated the great promise of La-doped BiFeO 3 in the elimination of antibiotic organics. • Different mole ratios of La doped BiFeO 3 have been synthesized. • La doped BiFeO 3 exhibits narrow band gap and excellent catalytic activity. • La doped BiFeO 3 is an efficient photo-Fenton catalyst for Norfloxacin degradation. • Hydroxyl radicals and holes are the main active species in this process. • The detailed reaction process for degradation over La doped BiFeO 3 is illustrated. [ABSTRACT FROM AUTHOR]

The activation of peroxymonosulfate (PMS) by redox-active quinones-like compounds has been proposed as a viable approach for water decontamination, which is, however, limited by the secondary pollution associated with ex situ addition of organic activators. Herein, we demonstrated a novel in situ produced quinone intermediates-mediated PMS activation technique for organic decontamination. The parent pollutant (e.g., aniline) was first transformed to quinones-like intermediates by electrooxidation, followed by nucleophilic addition with PMS to initiate the production of singlet oxygen (1O 2), which significantly improved the pollutant degradation and mineralization kinetics when compared to conventional electrooxidation technologies. Advanced characterizations and experimental evidence showed that the proposed method could significantly reduce electrode fouling, which is a common limitation of electrooxidation processes. The system could function efficiently across a pH range of 3–11. Experiments with genuine aniline-contaminated dyeing effluent confirmed the excellent system efficacy. [Display omitted] • An electrogenerated quinone intermediate-mediated PMS activation system was proposed. • The system enabled simultaneous water purification and electrode antifouling. • Theoretical calculations and experimental evidence collectively verified the key role of 1O 2. • Excellent system efficacy could be obtained across a wide pH range. [ABSTRACT FROM AUTHOR]

• Using formaldehyde as an actinometer to determine VUV 185 photon flux was studied. • A good correlation between C 0 × k values and photon flux was established. • pH, DO, temperature, and HCO 3 – all posed little effect on the use of formaldehyde. • Formaldehyde was comparable to methanol for photon analyses in three photoreactors. Quantifying ultraviolet (UV) photon flux is important for water photolysis practice. However, it is currently challenging to quantify the photon flux of 185 nm vacuum UV (VUV 185) emitted by low-pressure mercury lamp (LPML) because of the interference of coexisting 254 nm UV (UV 254). Given that formaldehyde (FA) is insensitive to UV 254 within the time scale of interests whereas vulnerable to VUV 185 , this study for the first time evaluated the possibility of using FA as a chemical actinometer to determine the VUV 185 photon flux under varying conditions. Experimental results revealed that the photodegradation of FA followed a pseudo -1st-order reaction kinetic under VUV 185 irradiation, and the products of initial concentration (C 0) and reaction rate constants (i.e., C 0 × k) were proportional to the numbers of LPMLs (under C 0 of 50–300 mg/L), suggesting that C 0 × k is an excellent indicator for photon flux determination. Increasing dissolved oxygen concentration from 1.0 to 7.8 mg/L, pH from 4.0 to 10.4, and temperature from 22 to 44 °C all imposed negligible interferences (variation ≤ 10%) on the C 0 × k values, proving that FA is a good actinometer for VUV 185 photon flux detection. Because FA can be measured readily by spectrophotometry method, its use as an actinometer is more convenient than conventional actinometers. Therefore, this study demonstrates that FA is a promising candidate of actinometer for VUV 185 quantification in the copresence of UV 254. [ABSTRACT FROM AUTHOR]

The transformation of organic matters in swine, cow and chicken manures was compared and evaluated using elemental analysis, FTIR, 13 C NMR, pyrolysis/GC/MS, Biolog and multiple fluorochrome over 60 days composting. The results revealed that cow manure exhibited the greatest C/N and aromaticity, whereas chicken manure exhibited the highest nitrogen and sulfur contents. O-alkyl-C was predominant carbon structure in the three manures. Alkyl-C and carboxyl-C were decomposed dramatically in initial 10 days, and mineralization of O-alkyl-C dominated the curing stage. During pyrolysis of chicken, cow, and swine manures, the majority products were fatty acids, phenols and cholestene derivatives, respectively, however, phenols and cholestene derivatives were strongly reduced in the mature manures. Furthermore, microorganisms in the raw cow, chicken and swine manure demonstrated the highest degradation capabilities for carbohydrates, lipids and amino acids, respectively. Spatial differences in the contents of solid organics in the manure particles were negligible through detection by multiple staining methods during composting. [ABSTRACT FROM AUTHOR]

The present work aims to ascertain the mechanisms of surfactant (dodecylbenzene sulfonate; DBS) effects on the aggregation behaviors of TiO 2 nanoparticles (TiO 2 -NPs) in natural water samples. Aggregation experiments were conducted at a TiO 2 -NPs concentration of 10 mg/L in deionized water and in natural water samples via dynamic light scattering and Zeta potential determination. Average attachment efficiency was calculated to compare the aggregation behaviors of nanoparticles in the two aqueous media. Results showed that the effects of DBS on aggregation could be interpreted by both Derjaguin–Landau–Verwey–Overbeek (DLVO) and non-DLVO mechanisms. In natural water samples, aggregation did not occur rapidly and was able to develop slowly under all conditions, and the roles of DBS were obvious at high DBS concentration owing to the impacts of inherent components of natural water samples, such as colloids and natural organic compounds. Future aggregation studies should concentrate on multi-factor, multi-colloidal and dynamic aspects under similar environmental conditions. [ABSTRACT FROM AUTHOR]

• PB-film electrode can selectively adsorb NH 4 + by intercalation. • Electroswitchability of PB imparts NH 4 + adsorption/desorption reversibility. • Quantitative relationship is established between NH 4 + adsorption and color matrix. • Self-reporting electroswitchable colorimetric platform is developed for NH 4 + recovery. Recovery of ammonium from wastewater represents a sustainable strategy within the context of global resource depletion, environmental pollution and carbon neutralization. The present study developed an advanced self-reporting electroswitchable colorimetric platform (SECP) to realize smart ammonium recovery based on the electrically stimulated transformation of Prussian blue/Prussian white (PB/PW) redox couple. The key to SECP was the selectivity of ammonium adsorption, sensitivity of desorption to electric signals and visualability of color change during switchable adsorption/desorption transformation. The results demonstrated the electrochemical intercalation-induced selective adsorption of NH 4 + (selectivity coefficient of 3–19 versus other cations) and deintercalation-induced desorption on the PB-film electrode. At applied voltage of 1.2 V for 20 min, the negatively charged PB-film electrode achieved the maximum adsorption capacity of 3.2 mmol g−1. Reversing voltage to −0.2 V for 20 min resulted in desorption efficiency as high as 99%, indicating high adsorption/desorption reversibility and cyclic stability. The Fe(III)/Fe(II) redox dynamics were responsible for PB/PW transformation during reversible intercalation/deintercalation of NH 4 +. Based on the blue/transparence color change of PB/PW, the quantitative relationship was established between amounts of NH 4 + adsorbed and extracted RGB values by multiple linear regression (R 2 = 0.986, RMSE = 0.095). Then, the SECP was created upon the unique capability of real-time monitoring and feedback of color change of electrode to realize the automatic control of NH 4 + adsorption/desorption. During five cycles of tests, the adsorption process consistently peaked at an average value of 3.15±0.04 mmol g−1, while desorption reliably approached the near-zero average of 0.06±0.04 mmol g−1. The average time of duration was 19.6±1.67 min for adsorption and 18.8±1.10 min for desorption, respectively. With electroswitchability, selectivity and self-reporting functionalities, the SECP represents a paradigm shift in smart ammonium recovery from wastewater, making wastewater treatment and resource recovery more efficient, more intelligent and more sustainable. [Display omitted] [ABSTRACT FROM AUTHOR]

Here, we demonstrate an integrated fluidic sequential electrochemical system for effective water decontamination. The system consists of a Ti mesh anode deposited with nanoscale IrO 2 and a CNT filter functionalized with nanoconfined Fe 2 O 3. By conducting anodic oxygen evolution reaction (OER) and 2e– oxygen reduction reaction (ORR) sequential electrolysis, our system enables sustainable O 2 generation at the anode, followed by transformation of O 2 into H 2 O 2 at the cathode, which then led to the production of 1O 2 in the presence of nanoconfined Fe 2 O 3. No chemical inputs were needed nor side products occurred during the whole sequential electrochemical processes. The effectiveness of the system was evaluated using tetracycline as a model emerging contaminant. Recirculating at 3 mL min–1, the system exhibited negligible iron and iridium leaching (≤0.01 mg L–1) and high tetracycline degradation efficiency (≥95%). Such excellent efficacy can be maintained across a wide pH range and in complicated water matrices. [Display omitted] • An "O 2 self-feeding" fluidic bipolar electrochemical system was designed. • The system combines oxygen/water (O 2 /H 2 O) redox couple. • The system shows negligible Fe and Ir loss and high organic degradation efficiency. • The essential role of 1O 2 was identified toward selective organic degradation. • No chemical inputs were needed nor side products occurred during the reaction. [ABSTRACT FROM AUTHOR]

Doxorubicin (Dox) is a potent antineoplastic agent, but its use is curtailed by severe cardiotoxicity, known as Dox-induced cardiomyopathy (DIC). The molecular mechanism underlying this cardiotoxicity remains unclear. Our current study investigates the role of Ubiquitin-Specific Protease 36 (USP36), a nucleolar deubiquitinating enzyme (DUB), in the progression of DIC and its mechanism. We found increased USP36 expression in neonatal rat cardiomyocytes and H9C2 cells exposed to Dox. Silencing USP36 significantly mitigated Dox-induced oxidative stress injury and apoptosis in vitro. Mechanistically, USP36 upregulation positively correlated with Poly (ADP-ribose) polymerase 1 (PARP1) expression, and its knockdown led to a reduction in PARP1 levels. Further investigation revealed that USP36 could bind to and mediate the deubiquitination of PARP1, thereby increasing its protein stability in cardiomyocytes upon Dox exposure. Moreover, overexpression of wild-type (WT) USP36 plasmid, but not its catalytically inactive mutant (C131A), stabilized PARP1 in HEK293T cells. We also established a DIC model in mice and observed significant upregulation of USP36 in the heart. Cardiac knockdown of USP36 in mice using a type 9 recombinant adeno-associated virus (rAAV9)-shUSP36 significantly preserved cardiac function after Dox treatment and protected against Dox-induced structural changes within the myocardium. In conclusion, these findings suggest that Dox promotes DIC progression by activating USP36-mediated PARP1 deubiquitination. This novel USP36/PARP1 axis may play a significant regulatory role in the pathogenesis of DIC. • Deficiency in USP36 provides a protective effect against cardiac oxidative stress injury and apoptosis induced by Dox. • USP36 interacts with PARP1, and it is through this interaction that USP36 influences the regulation of cardiac injury. • This research broadens our understanding of the USP family's role in cardiovascular diseases. [ABSTRACT FROM AUTHOR]

• Polarity distribution of anammox EPS was quantified by XAD resin fractionation. • Anammox aggregation relied on the hydrophobicity and gel properties of EPS. • Large amounts of tryptophan-like substances contributed to hydrophobic interactions. • Increased β -sheet and reduced β -turn favored the exposure of hydrophobic groups. • High levels of α -helix and n pr enhanced EPS gel strength and mechanical stability. The chemical characteristics of extracellular polymeric substances (EPS) of anammox bacteria (AnAOB) play a crucial role in the rapid enrichment of AnAOB and the stable operation of wastewater anammox processes. To clarify the influential mechanisms of sludge EPS on AnAOB aggregation, multiple parameters, including the polarity distribution, composition, and molecular structure of EPS, were selected, and their quantitative relationship with AnAOB aggregation was analyzed. Compared to typical anaerobic sludge (anaerobic floc and granular sludge), the anammox sludge EPS exhibited higher levels of tryptophan-like substances (44.82–56.52 % vs. 2.57–39.81 %), polysaccharides (40.02–53.49 mg/g VSS vs. 30.22–41.69 mg/g VSS), and protein structural units including α -helices (20.70–23.98 % vs. 16.48–19.32 %), β -sheets (37.43–42.98 % vs. 25.78–36.72 %), and protonated nitrogen (N pr) (0.065–0.122 vs. 0.017–0.061). In contrast, it had lower contents of β -turns (20.95–27.39 % vs. 28.17–39.04 %). These biopolymers were found to originate from different genera of AnAOB. Specifically, the α -helix-rich proteins were mainly derived from Candidatus Kuenenia , whereas the extracellular proteins related to tryptophan and N pr were closely associated with Candidatus Brocadia. Critically, these EPS components could drive anammox aggregation through interactions. Substantial amounts of tryptophan-like substances facilitated the formation of β -sheet structures and the exposure of internal hydrophobic clusters, which benefited the anammox aggregation. Meanwhile, extracellular proteins with high N pr content played a pivotal role in the formation of mixed protein-polysaccharide gel networks with the electronegative regions of polysaccharides, which could be regarded as the key component in the maintenance of anammox sludge stability. These findings provide a comprehensive understanding of the multifaceted roles of EPS in driving anammox aggregation and offer valuable insights into the development of EPS regulation strategies aimed at optimizing the anammox process. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, we developed and evaluated an electrochemical periodate (PI) activation system for the ultrafast degradation of aqueous micropollutants (τ < 3 s). Filters constructed from carbon nanotubes (CNT) coated with Fe 2 O 3 nanoparticles on the outer (Fe 2 O 3 -out-CNT) and inner surfaces (Fe 2 O 3 -in-CNT) were prepared to regulate the generation of reactive oxygen species (ROS) during PI activation. The activation function of the electroactive nanohybrid filters lay in their ability to facilitate the redox cycling of Fe(III)/Fe(II) assisted by an electric field. The results showed that a non-radical (i.e., 1O 2) pathway dominated the degradation process in the electro/Fe 2 O 3 -in-CNT/PI system, while a contrastive radical pathway (i.e., HO• and IO 3 •) was identified in the electro/Fe 2 O 3 -out-CNT/PI system. The electro/Fe 2 O 3 -in-CNT/PI system exhibited enhanced catalytic activity towards the micropollutants degradation relative to its electro/Fe 2 O 3 -out-CNT/PI counterpart. Density functional theory calculations suggested that PI could be directly decomposed under the nanoconfined environment, rather than forming a stable adsorption complex in the unconfined system. [Display omitted] • An electrochemical PI activation system was developed for ultrafast water remediation. • Non-radical pathway dominated BPA degradation in the E/Fe 2 O 3 -in-CNT/PI system. • Radical pathway was identified in the E/Fe 2 O 3 -out-CNT/PI system. • Ultrafast and robust organic degradation were obtained in the E/Fe 2 O 3 -in-CNT/PI system. • IO 4 − were transformed into nontoxic IO 3 − without generation of undesired I species. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni 3 Se 4 flowers integrated with ultrathin carbon layer are used as ORR/OER catalysts. • Tight connection between Ni 3 Se 4 and UCL generates numerous active interfaces for ORR. • Ni2+ acts as an initiator to create β-NiOOH as highly-active surface species for OER. • Strong electronic interactions help to obtain efficient charge transfer for ORR/OER. • Ultrathin carbon layer protects Ni 3 Se 4 from aggregation and corrosion during ORR/OER. Transition metal selenides have shown unexpectedly-high activity for oxygen reduction and oxygen evolution reactions (ORR/OER) in alkaline media. However, many fundamental issues regarding the effects of catalyst structure on ORR/OER activities with enhanced stability still remain unknown. Here we prepare three-dimensional (3D) flower-like Ni 3 Se 4 coated by ultrathin carbon-layer (Ni 3 Se 4 /UCL) as bifunctional catalyst. Distribution (mapping) of C and N elements confirms the firm combination of Ni 3 Se 4 with UCL to form flower petals with convex-concave surface. Ni 3 Se 4 /UCL-3 (mass ratio of NiCl 2 ·6H 2 O/carbon is 3) exhibits an excellent half-wave potential of 0.82 V (E 1/2 , ORR) and a promising overpotential of 0.35 V at 10 mA cm−2 (OER). Ni 3 Se 4 /UCL-3 has a negative shift of only 12 mV for E 1/2 after 5000 cycles (ORR) and a current density decline of only 7.34 % after 20 h test (OER). Density functional theory calculations reveal that interfacial charge redistribution behaviors including charge accumulation and depletion lead to strong electronic interactions between Ni 3 Se 4 (0 0 2) and UCL to obtain efficient charge transfer for ORR/OER. β-NiOOH is mainly responsible for the high OER activity, and in-situ X-ray diffraction tests verify the crystallization of selenite (NiSeO 3) during OER. This work provides a promising reference for promoting future development of 3D-structured transition metal selenides-based electrocatalysts. [ABSTRACT FROM AUTHOR]