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Global warming has seriously threatened the industrial/agricultural productions and human life and has become one of the major challenges facing the world today. Carbon neutrality is an important measure for mitigating the greenhouse effect, and photocatalytic CO2reduction can effectively reduce carbon emissions and promote the carbon cycle. g-C3N4has attracted much attention due to its simple preparation process, high stability, suitable energy band position, and excellent photocatalytic performance; thus, improving its efficiency in photocatalytic CO2reduction has become the focus of current research. The importance of carbon neutrality for the global ecological balance and environmental sustainability and the important role and development prospects of g-C3N4photocatalytic CO2reduction in the context of carbon neutrality are the main focuses of this review. The current methods and technical means to solve the difficulty of the g-C3N4photocatalytic CO2reduction are summarized. The possible problems in the field of g-C3N4photocatalytic CO2reduction are discussed, and future research directions are proposed. The aim of this work is to provide theoretical support for the practical applications of g-C3N4photocatalytic CO2reduction and to present potential design concepts for efficient g-C3N4-based photocatalysts.

The catalytic removal of chlorinated VOCs (CVOCs) in gas–solid reactions usually suffers from chlorine-containing byproduct formation and catalyst deactivation. AOP wet scrubber has recently attracted ever-increasing interest in VOC treatment due to its advantages of high efficiency and no gaseous byproduct emission. Herein, the low-valence Co nanoparticles (NPs) confined in a N-doped carbon nanotube (Co@NCNT) were studied to activate peroxymonosulfate (PMS) for efficient CVOC removal in a wet scrubber. Co@NCNT exhibited unprecedented catalytic activity, recyclability, and low Co ion leakage (0.19 mg L–1) for chlorobenzene degradation in a very wide pH range (3–11). The chlorobenzene removal efficiency was kept stable above 90% over Co@NCNT, much higher than that of nonconfined Co@NCNS (45%). The low-valence Co NPs achieved a continuous electron redox cycling (Co0/Co2+→ Co3+→ Co0/Co2+) and greatly promoted the O–O bond dissociation of PMS with the least energy (0.83 eV) inside the channel of Co@NCNT to form abundant HO•and SO4•–. Thus, the deep oxidation of chlorobenzene was achieved without any biphenyl byproducts from the coupling reaction. This study provided a new avenue for designing novel nanoconfined catalysts with outstanding activity, paving the way for the deep oxidation of CVOC waste gas via AOP wet scrubber.

Photocatalytic water splitting using semiconductor photocatalysts is a promising approach for the production of carbon-neutral, sustainable and clean hydrogen fuel. However, the separation and transport of photoinduced carriers are generally considered to be rate-limiting steps, and their low efficiency remains a major challenge. Therefore, much effort has been devoted to developing new strategies in surface/interface engineering of photocatalysts to improve the dynamics of charge separation/transport. This feature article briefly summarizes recent advances in photocatalyst surface/interface engineering by our research group, which have been achieved through the design of various novel photocatalysts, including interfacial modulation, heterostructure construction, heteroatom doping, single atom and diatom sites. The article is divided into three parts: first, we briefly introduce the three key processes involved in solar water splitting and reveal relationships between the properties of nanostructural photocatalysts and the fundamentals of water splitting; second, we detail methods and strategies for surface and interfacial structures to improve the efficiency of the fundamental processes, especially charge separation; finally, we explore prospects for photocatalytic water splitting applications. This article provides a valuable resource and strategies for researchers currently working in the field of photocatalytic water splitting.

Improving the reaction rate of each step is significant for accelerating the multistep reaction of NO reduction by H2. However, simultaneously enhancing the activation of different gaseous reactants using single-atom catalysts remains a challenge to maximize the activity. Herein, we propose a strategy that utilizes titanium-vacancy-regulated electronic properties of single atoms and defective support (Pt1/d-TiO2) to facilitate electron transfer from edge-share O atoms (OTi) to adjacent Pt single atoms. This leads to the formation of low-valence Pt and unsaturated-charge OTisites, which causes the catalytic reaction to follow a synergistic mechanism. Specifically, experimental and theoretical analyses demonstrate that low-valence Pt sites finely tune the adsorption of H2molecules, consequently lowering the dissociation energy from 0.15 to as low as 0.01 eV. Moreover, using quasi-in situ spectroscopy, we clearly observe NO molecules being adsorbed on interfacial oxygen sites of a defective support. Then, the bond energy of the N–O bond is weakened through an electron acceptance–donation mechanism between unsaturated-charge OTisites and NO, thereby facilitating NO activation. The designed single-atom catalysts with synergistic sites exhibit unmatched activity at low temperatures (above 90% NOxconversion at 100 °C), along with higher turnover frequency value (0.74 s–1) and superior stability, making them potentially suitable for industrial applications.

The redox behavior of metal active sites determines the rate of heterogeneous catalysis in peroxymonosulfate activation. Previous reports focused on the construction of catalysts for accelerating interfacial electron transfer. In this work, a new strategy was proposed for facilitating valence cycles of Cu+/Cu2+by using pollutants. The 2.5Cu/CeO2/PMS system was capable of achieving the efficient removal of pollutants, including tetracycline, oxytetracycline, and rhodamine B, in a wide pH working range. In the presence of tetracycline, a Cu–N bond was formed between the −NH2group of tetracycline and the Cu site of the catalyst, showing that the coordination of Cu active sites changed to CuO4N1. The charge of CuO4N1active sites rearranged, making it easier to obtain electrons and promote the PMS oxidation, thereby accelerating the reduction of Cu2+to Cu+and PMS activation. The PMS activation system showed excellent sustainability and selectivity for the removal of organic pollutants. This study provides a novel routine to promote peroxymonosulfate activation by utilizing pollutants to accelerate the redox behavior of metal species.

The extensive burning of fossil fuels has caused energy shortages and worsened the greenhouse effect, posing a significant threat to human survival and development. The use of solar energy as a renewable source to reduce CO2emissions and produce green fuels and high-value chemicals is seen as a promising solution to the ongoing energy crisis. Ultrathin two-dimensional photocatalysts have large surface areas and numerous low-coordination surface atoms, giving them substantial potential for highly efficient photocatalytic performance. These materials can reduce carrier transmission distance, enhance reactant adsorption and activation (e.g., CO2and H2O), lower energy barriers, facilitate specific reactions, inhibit competing reactions, and regulate catalytic efficiency and selectivity. This article provides a concise overview of ultrathin two-dimensional semiconductor synthesis, clarifies catalytic mechanisms, explores various photocatalytic applications, and outlines strategies to enhance photoconversion performance. It also emphasizes the primary challenges and opportunities faced by ultrathin photocatalysts. We anticipate that this review will offer valuable insights for further research in two-dimensional photocatalysis and encourage the practical application of these unique materials in energy conversion.

Hydrogen peroxide (H2O2) is an important green oxidant with a wide range of applications in wastewater treatment, pulp bleaching and chemical synthesis. In recent years, two-electron oxygen reduction reaction (2e-ORR) is expected to be a greener and safer alternative to the anthraquinone process. Among the various electrocatalysts for 2e-ORR, two-dimensional nanomaterials have special advantages in the electrosynthesis of H2O2due to their large specific surface area, abundant basal and edge sites, and tunable atomic structure. This review article summarizes the synthesis methods, and the strategies and mechanisms for enhancing 2e-ORR properties of 2D materials. Practical problems and serious challenges faced by 2D nanomaterials in the synthesis and 2e-ORR applications are elaborated. The aim of this review is to provide researchers with an understanding of 2D nanomaterials in electrocatalytic applications and to promote the further development of novel 2D nanoelectrocatalytic materials.

The utilization of an efficient photocatalyst is crucial for the photocatalytic degradation of antibiotics in water through visible light, which is an imperative requirement for the remediation of water environments. In this study, a novel Cu-CeO2/BiOBr Z-type heterojunction was synthesized by calcination and hydrothermal methods, and the degradation rate of sulfathiazole (STZ) antibiotic solution was studied using simulated illumination (300W xenon lamp). The results indicated that 3% Cu-CeO2/BiOBr achieved a degradation rate of 92.3% within 90 minutes when treating 20 mg/L STZ solution, demonstrating its potential for practical water treatment applications. Characterization using various chemical instruments revealed that 3% Cu-CeO2/BiOBr exhibited the lowest electron-hole recombination rate and electron transfer resistance. Furthermore, the utilization of ESR data and quenching experiments has substantiated the involvement of hydroxyl radicals (•OH) and superoxide radicals (•O2−) as the primary active species. Consequently, a plausible degradation mechanism has been inferred. These findings offer a prospective approach for the development of heterojunction materials with appropriate band matching.

The long-term overuse of ciprofloxacin has resulted in its ubiquitous release into aquatic environments, seriously threatening public and ecological security. Herein, a photo-assisted-electro-Fenton-like (PAEF-like) system using p–n type Cu2O/Bi2MoO6(CBM) as photoelectric catalyst was designed for efficient ciprofloxacin removal. The realization of photo-assisted function benefited from the perfectly constructed p–n heterojunction, which effectively regulated the carrier migration behaviors and drove the directional delivery of photoinduced electrons with flexible reactivity. Furthermore, photoinduced electrons directly or indirectly promoted the activation of H2O2to enhance the ability of the PAEF-like synergy system to form OH, improving the photoelectric catalytic activity. As dominant active species, OH cooperated with h+and O2−, leading to the efficient elimination of ciprofloxacin. Finally, the degradation rate within 120 min reached almost 100%, and the corresponding kinetic constant was 208 and 1.5 times that of the photocatalytic and EF-like system, separately. Importantly, CBM-25% still maintained superior removal effect after four consecutive runs, revealing the high stability and practical feasibility of the PAEF-like system.

A novel strategy was developed to synthesize non-noble metal co-catalyst/solid solution heterojunctions using MOFs as a precursor template. The Cu1.8S(3.7%)/Zn0.35Cd0.65S sample exhibits a maximum hydrogen evolution rate of 14.27 mmol h−1 g−1with an apparent quantum yield of 3.7% at 420 nm under visible-light irradiation. This work has achieved the synergistic integration of photocatalytic components and functional heterostructures, providing an idea for creating new efficient solar-hydrogen conversion photocatalysts.

A range of Ag2O/BiOBr heterojunction photocatalyst was successfully prepared. The photocatalytic behaviors of prepared samples against E. coli, S. aureus, tetracycline and acetaminophen irradiated by visible light were studied. In contrast to pure Ag2O and BiOBr, Ag2O/BiOBr photocatalyst showed high disinfection activity with the optimal Ag2O amounts of 3 wt%, and it is efficiency for removal of multiple pollutants. Ag2O/BiOBr was proved to a potential AOP material for WWTPs.

To achieve high efficiency and low consumption for water treatment in the Fenton reaction, we use the surface oxygen vacancies (OVs) as the electron temporary residences to construct a dual-reaction-center (RDC) Fenton-like catalyst with abundant surface electron-rich/poor areas consisting of OV-rich Co-ZnO microparticles (OV-CoZnO MPs). The lattice-doping of Co into ZnO wurtzite results in the formation of OVs with unpaired electrons (electron-rich OVs) and electron-deficient Co3+sites according to the structural and electronic characterizations. Both experimental and theoretical calculations prove that the electron-rich OVs are responsible for the capture and reduction of H2O2to generate hydroxyl radicals, which quickly degrades pollutants, while a large amount of pollutants are adsorbed at the electron-deficient Co3+sites and act as electron donors for the system, accompanied by their own oxidative degradation. The electrons obtained from the pollutants in the electron-deficient sites are transferred to the OVs through the internal bond bridge to achieve the balance of electron gain/loss. Through this process, pollutants are efficiently converted and degraded by multiple pathways in a wide range of pH (4.5–9.5). The reaction rate of the OV-CoZnO MPs/H2O2system is increased by ∼17 times compared with the non-DRC system. This discovery provides a sustainable strategy for pollutant utilization, which shows new implications for solving the troublesome issues of the Fenton reaction and for developing novel environmental remediation technologies.

Several porous biochars with various surface area and defect degree were fabricated.These catalysts were used for peroxydisulfate activation to degrade sulfadiazine.The catalyst made by employing Na2S2O3and KCl exhibited the optimum performance.The surface area and C-sp3together determined quantitatively the catalytic effect.The single electron transfer from organic to inner-sphere catalyst/peroxodisulfate* was dominant.

Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, corrosion resistance, high viscosity, and nonabsorption by soil. The composite of Fe-doped Ce0.75Zr0.25O2solid solution (Fe-Ce0.75Zr0.25O2) loaded on carbon felt (CF) was fabricated by a hydrothermal synthesis method, which was used as the cathode in a heterogeneous electro-Fenton system for the degradation of PAM. It showed that the degradation efficiency of PAM by the Fe-Ce0.75Zr0.25O2/CF cathode was 86% after 120 min and the molecular mass of PAM decreased by more than 90% after 300 min. Total organic carbon removal reached 78.86% in the presence of Fe-Ce0.75Zr0.25O2/CF, while the value was only 38.01% in the absence of Fe-Ce0.75Zr0.25O2. Further studies showed that the breaking of the chain begins with the amide bond, and then, the carbon chain was cracked into a short alkyl chain. As degradation progressed, both the complex viscosity and elasticity modulus of PAM solutions decreased nearly 50% at 300 min. It indicated that •OH were the most significant active species for the degradation of PAM. This novel Fe-Ce0.75Zr0.25O2/CF composite is an efficient and promising electrode for the removal of PAM in wastewater.

Antibiotics accumulate because of their extensive use and difficult degradation, which can lead to the formation of novel antibiotic resistant genes and bacteria, which can cause damage to human health and the ecological environment. Here, we designed a novel photo-electro-Fenton-like (PEF-like) system with bifunctional Z-scheme WO3/g-C3N4for accelerated decomposition and enhanced mineralization of stubborn ciprofloxacin (CIP). This PEF-like system, accompanied by visible light activation, with the optimal WO3/g-C3N4(1 : 6) composite exhibited outstanding removal efficiency of CIP compared with a single photocatalysis system and electro-Fenton-like (EF-like) system, and the elimination rate reached 100% within 2 h under visible light irradiation. The WO3/g-C3N4(1 : 6) composite displayed the strongest visible light absorption, the weakest recombination of electron–hole pairs, the highest photocurrent response and the lowest electrochemical impedance compared with pristine WO3and g-C3N4. Significantly, WO3/g-C3N4(1 : 6) played a dual role in the PEF-like system which could not only produce OH, O2−and h+during photocatalysis, but could also generate OH through the reactions of W5+and photoexcited electrons of g-C3N4for the decomposition of H2O2. It was worth noting that this bifunctional PEF-like catalyst with photoelectric synergy could replace Fe2+in a conventional electro-Fenton reaction and the pH range was broadened while still maintaining efficient degradation efficiency in the range of 2–9. The PEF-like system maintained a high elimination rate of CIP after five consecutive runs which revealed that it possessed prominent stability and feasibility.

An electro-Fenton-like process was extensively applied to eliminate ciprofloxacin antibiotics pollution in water systems. Here, we developed ordered meso-NiMn2O4nanoparticles as an efficient electro-Fenton-like catalyst to modify a CF cathode for the degradation and mineralization of ciprofloxacin (CIP). It was found that the carbon felt (CF) cathode modified by the meso-NiMn2O4catalyst could improve the generation of H2O2, which thereby demonstrated the excellent catalytic property and electrochemical performance. Significantly, the mesoporous architecture of this Fenton-like catalyst provided more activated sites and interconnected channels that could accelerate electron transfer and facilitate the generation of activated radicals (OH and O2−). It is worth mentioning that the bifunctional meso-NiMn2O4catalyst could provide two redox couples (Mn4+/Mn3+and Ni3+/Ni2+) to enhance the electro-Fenton-like reaction for increasing the generation rate of active radicals. The degradation efficiency of CIP finally reached 100% within 1.5 h by using the meso-NiMn2O4catalyst, which was better than that of other as-prepared Fenton-like catalysts, such as bulk-NiMn2O4, meso-MnO2, and meso-NiO. Simultaneously, TOC removal of CIP for the meso-NiMn2O4catalyst was twice than that of bulk-NiMn2O4catalyst. Finally, a possible heterogeneous electro-Fenton-like reaction mechanism for the efficient destruction of CIP was proposed by using the ordered meso-NiMn2O4catalyst.

In spite of intensive research investigating the prevalent Pt/Al2O3catalysts, achieving macroscopic morphology beyond the powder form limitations remains highly challenging. Meanwhile, current impregnation-based preparation approaches show the drawbacks of tedious procedures and inefficient use of noble metals. Therefore, it is important to search for new methods for the fabrication of Pt/Al2O3catalysts with a novel morphology. In this study, a novel Pt/Al2O3nanofibrous membrane catalyst is fabricated via a facile one-pot electrospinning process. The embedding of Pt nanoparticles is performed simultaneously with the formation of Al2O3nanofibers. The Pt/Al2O3membranes show remarkable mechanical properties with tensile stresses as high as 44.14 MPa. Notably, the Pt/Al2O3membranes exhibit multifunctionality with excellent performance characteristics. The catalytic experiments indicate that 100% of bisphenol A is removed within 60 min, and 100% of CO is completely converted to CO2at 242 °C when Pt/Al2O3membranes are used as catalysts. The membranes also exhibit excellent filtration performance, clearly decreasing the turbidity of water, and meet the high efficiency of particulate air filter standards. The excellent flexibility, satisfying mechanical property, and multifunctionality extend the range of potential application of the Pt/Al2O3membranes. Moreover, the facile synthesis suggests new possibilities for the fabrication of many membrane-form Al2O3-supported catalysts.

In order to remove NOxfrom multiple sources with complex operating conditions, catalysts with excellent low-temperature activity and strong water and sulfur resistance are in high demand. Herein, we designed an efficient inter-connected porous CuOx-NbOx/kit-CeO2catalyst for the selective catalytic reduction of NOxwith NH3(NH3-SCR). The catalyst exhibited relatively outstanding NH3-SCR activity in the low temperature range (100–300 °C) and showed remarkable stability and excellent resistance to SO2and H2O. The inter-connected porous structure allowed the adsorption and diffusion of gaseous reactants, meanwhile, the interaction between Cu, Nb and Ce enhanced the surface acidity, redox properties and surface oxygen activity of the CuOx-NbOx/kit-CeO2catalyst. On the basis of in situDRIFTs studies, Eley-Rideal process was expected to be the dominant pathway with the coexistence of Langmuir–Hinshelwood mechanism at 250 °C.

In this work, 3D columnar CexZr1−xO2/RGO composite electrodes are prepared based on a hydrothermal self-assembly method, which were used as cathodes to degrade ciprofloxacin (CIP) for the first time in an electro-Fenton system. The composite was fully characterized using TEM, XRD, BET, XPS, CV and EIS. Moreover, it can be found that the Ce0.75Zr0.25O2/RGO composite electrode exhibited a superior degradation efficiency for CIP, compared with the CeO2/RGO electrode. The enhanced degradation efficiency originates from synergistic effects of the electrosorption of 3D RGO, Ce0.75Zr0.25O2electrocatalysis and powerful oxidation of hydroxyl radicals (OH). CIP was completely degraded within 5 h and the TOC removal efficiency reached 96.38%. The Ce0.75Zr0.25O2/RGO composite cathode is a prospective candidate for degradation of CIP in an electro-Fenton system.

The solar-driven photocatalytic process has been evolved as a promising technology for both hexavalent chromium reduction and organic pollutants oxidation. Although both reactions are based on the same principle of photoinduced interfacial charge transfer, different catalysts and reaction conditions are required in two processes. This review revealed the scientific advances in dual-functional photocatalytic processes that enable simultaneous hexavalent chromium reduction and organics oxidation. Firstly, the basic principles of dual-functional photocatalysis are briefly discussed whereby the key concept of the system is the simultaneous oxidation of organic pollutants via photogenerated holes and reduction of hexavalent chromium via photogenerated electrons. Then, advances in dual-functional photocatalysis for the simultaneous removal of hexavalent chromium and organics are presented and discussed in terms of catalysts classification, including TiO2-based, bismuth-based and g-C3N4-based catalysts. Finally, the prospects, challenges and new perspectives of feasible solutions for dual-functional photocatalytic catalysts design are presented. Overall, this paper provides new insights on the modulation strategies and conformational relationships of dual-functional materials for researchers in the field of photocatalysis, which is beneficial for the practical applications of dual-functional materials in environmental remediation.

Acidity is a crucial factor limiting the application of ceria-based catalyst for selective catalytic reduction (SCR) of NOxwith NH3. Unravelling the participation mechanism of acid sites on ceria-based catalyst is imperative but still lacking. Herein, by tuning the electronic interaction between MoOxand CeO2nanosheet with numerous pits (P-CeO2) via controlling the number of surface pits of P-CeO2, we demonstrate that electronic interaction strongly determines the acidity properties of catalyst to modulate the catalytic performance. The MoOx/P-CeO2exhibits much better catalytic activity, N2selectivity and tolerance to SO2and H2O than MoOx/CeO2with few pits in a temperature range of 250–400 °C with a gas hourly space velocity (GHSV) of 60,000 h−1, which is due to the highly dispersion of Mo-O-Mo structure over P-CeO2as determined by Raman. Furthermore, XPS and DFT calculations demonstrate that electrons transfer from P-CeO2to MoOxresult in a unique dynamic transformation from Brønsted acid site to Lewis acid site, enhancing the catalytic activity. This work increases the acidity sites on the catalyst by regulating the electron oxide-support interaction, which provides a new strategy for designing highly efficient ceria-based SCR catalysts.

TiO2–Bi2WO6binanosheet (TBWO), synthesized by a facile two-step hydrothermal method, was used as an effective visible-light-driven photocatalyst for the inactivation of E. coliand was characterized by TEM, SEM, XRD, FTIR, XPS, and BET. A series of TBWOs with different doping ratios of TiO2loading from 10 to 55 wt % were synthesized. Among all of the TBWOs, 40% TBWO exhibited the best bacteria disinfection efficiency, and the quantity of viable bacteria could reach 10° with 40% TBWO (100 μg/mL) after being illuminated for 4 h. Furthermore, the confocal fluorescent-based cell live/dead test and the SEM technology were applied to verify the photocatalytically lethal effect toward E. coliand the rupture of bacterial membranes. The leak of bacterial contents, including the bacterial genome represented by relevant 16srDNA, and total protein were detected by PCR and bicinchoninic acid assay. In this work, the antibacterial mechanism was studied by employing photoelectrochemical techniques, electron spin resonance (ESR), and scavengers of different reactive species, revealing the pivotal roles of electron hole (h+) and electron (e–) in the photocatalytic process. In addition, the •O2–and •OH radicals were also detected in the TBWOs system by ESR. It was found that the adsorption of visible light and separation of photogenerated carriers within TiO2have been largely promoted after being coupled with Bi2WO6, which should be responsible for the improved bactericidal effect.

Mn2O3-doped Fe2O3hexagonal microsheets were prepared for the low-temperature selective catalytic reduction (SCR) of NO with NH3. These hexagonal microsheets were characterized by SEM, TEM, XRD, BET, XPS, NH3-TPD, H2-TPR, and in situ DRIFT and were shown to exhibit a considerable uniform hexagonal microsheet structure and excellent low temperature SCR efficiency. When doped with different Mn molar ratios, Mn2O3was detected in the Fe2O3hexagonal microsheets based on the XRD results without the presence of other MnOXspecies. In addition, the hexagonal microsheets with a Mn/Fe molar ratio of 0.2 showed the best SCR removal performance among the materials, where a 98% NO conversion ratio at 200 °C at a space velocity of 30 000 h–1was obtained. Meanwhile, excellent tolerances to H2O and SO2, as well as high thermal stability, were obtained in Mn2O3-doped Fe2O3hexagonal microsheets. Moreover, on the basis of the XPS and in situ DRIFT results, it can be suggested that coupled Mn2O3nanocrystals played a key role at low temperatures and produced a possible redox reaction mechanism in the SCR process.

Ag-CoFe2O4-graphene oxide (Ag-CoFe2O4-GO) nanocomposite was synthesized by doping silver and CoFe2O4nanoparticles on the surface of GO, which was used to purify both bacteria and Pb(II) contaminated water. The Ag-CoFe2O4-GO nanomaterial was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), and magnetic property tests. It can be found that Ag-CoFe2O4-GO nanocomposite exhibited excellent antibacterial activity against Gram-negative Escherichia coliand Gram-positive Staphylococcus aureuscompared with CoFe2O4, Ag-CoFe2O4, and CoFe2O4-GO composite. This superior disinfecting effect was possibly attributed to the combination of GO nanosheets and Ag nanoparticles. Several antibacterial factors including temperature, time, and pH were also investigated. It was obvious that E. coliwas more susceptible than S. aureustoward all the four types of nanomaterials. The structural difference of bacterial membranes should be responsible for the resistant discrepancy. We also found that Ag-CoFe2O4-GO inactivated both bacteria in an irreversibly stronger manner than Ag-CoFe2O4and CoFe2O4-GO. The Pb(II) removal efficiency with all the nanomaterials showed significant dependence on the surface area and zeta potential of the materials. In this work, not only did we demonstrate the simultaneous superior removal efficiency of bacteria and Pb(II) by Ag-CoFe2O4-GO but also the antibacterial mechanism was discussed to have a better understanding of the interaction between Ag-CoFe2O4-GO and bacteria. In a word, taking into consideration the easy magnetic separation, bulk availability, and irreversibly high antibacterial activity of Ag-CoFe2O4-GO, it is the very promising candidate material for advanced antimicrobial or Pb(II) contaminated water treatment.

Magnetic Fe3O4/graphene composite (abbreviated as G-Fe3O4) was synthesized successfully by solvothermal method to effectively remove both bacteriophage and bacteria in water, which was tested by HRTEM, XRD, BET, XPS, FTIR, CV, magnetic property and zeta-potential measurements. Based on the result of HRTEM, the single-sheet structure of graphene oxide and the monodisperse Fe3O4nanoparticles on the surface of graphene can be observed obviously. The G-Fe3O4composite were attractive for removing a wide range of pathogens including not only bacteriophage ms2, but also various bacteria such as S. aureus, E. coli, Salmonella, E. Faecium, E. faecalis, and Shigella. The removal efficiency of E. colifor G-Fe3O4composite can achieve 93.09%, whereas it is only 54.97% with pure Fe3O4nanoparticles. Moreover, a detailed verification test of real water samples was conducted and the removal efficiency of bacteria in real water samples with G-Fe3O4composite can also reach 94.8%.

Fe3O4-TiO2nanosheets (Fe3O4-TNS) were synthesized by means of lamellar reverse micelles and solvothermal method, which were characterized by TEM, XRD, XPS, BET, and magnetic property analysis. It can be found that Fe3O4-TNS nanosheets exhibited better photocatalytic antibacterial activity toward Gram-negative Escherichia coliand Gram-positive Staphylococcus aureusthan pure Fe3O4and TNS, and the antibacterial efficiency could reach 87.2% and 93.7% toward E. coliand S. aureuswith 100 μg/mL Fe3O4-TNS after 2 h of simulated solar light illumination, respectively. The photocatalytic destruction of bacteria was further confirmed by fluorescent-based cell live/dead test and SEM images. It was uncovered that Fe3O4-TNS inactivated G- E. coliand G+ S. aureusby different mechanisms: the destruction of outer membranes and ruptured cell bodies were responsible for the bactericidal effect against E. coli, while the antibacterial effect toward S. aureuswere due to the fact that the cells were adsorbed in form of clusters by massive Fe3O4-TNS, which could restrict their activities and cause malfunction of the selective permeable barriers. Furthermore, the antibacterial mechanism was studied by employing scavengers to understand exact roles of different reactive species, indicating the key roles of h+and H2O2. The recovery and reusability experiments indicated that Fe3O4-TNS still retained more than 90% bacteria removal efficiency even after five cycles. Considering the easy magnetic separation, bulk availability, and high antibacterial activity of Fe3O4-TNS, it is a promising candidate for cleaning the microbial contaminated water environment.

Both waste management and cleaner production (CP) are playing a crucial role in reducing consumption of energy, water and raw materials, in addition to avoiding waste generation. Through investigating one typical gravure plate-making industry in Tianjin, PR China, waste management and cleaner production audit (CPA) have been used to find important opportunities for cleaner production. In this waste management process, three major technical innovations have been proposed and applied in this company. Through the first-round cleaner production audit, 0.68 million USD can be saved during one year. By the way, cost-effectiveness of the suggested programs is increased obviously compared with traditional production technology, which is important and conductive to the promotion of these novel technical progresses for other gravure plate-making industry in China.

Magnetic mesoporous γ-Fe2O3@Ti0.9Si0.1O2(abbreviated as Fe@TiSi) core–shell nanofibers were prepared using sol–gel chemistry combined with coaxial-electrospinning technology by adjusting the inner and outer feed ratios. The properties of these novel core–shell nanofibers were characterized by SEM, HRTEM, XRD, FTIR, BET, XPS, and UV–vis spectra. To evaluate the chemical properties of the nanofibers for cleaning typical organic wastewater, methylene blue (MB) was used as a target organic pollutant and was cleaned under irradiation with sunlight and visible light. The Fe@TiSi hierarchical nanofibers composed of a 1:10 feed ratio displayed a mesoporous structure and showed the highest photocatalytic activity for the degradation of MB in water. Furthermore, 86.8% and 71.1% of the MB, which was added at an original concentration of 1 mg/L, was removed after 60 min of irradiation with sunlight and visible light in the presence of Fe@TiSi at a concentration of 0.2 g/L, and 100% of the MB was removed after 75 min. It is very important that the magnetic nanofibers could be recycled rapidly with an outside magnet, and the actual water treatment process was easy to achieve. Moreover, the mechanism of MB degradation by Fe@TiSi core–shell nanofibers was proposed.

Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH3-SCR. Herein, we design a novel WOx/Cu-CeO2oxide catalyst in which the WOxspecies are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO2nanospheres, which exhibits great deNOxactivity advantage and wide operating temperature window (200–400 °C, over 85% NOxconversion with a gas hourly space velocity (GHSV) of 60,000 h−1), as well as good sulfur resistance and N2selectivity. The relationship among the composition, acidity and redox properties of the WOx/Cu-CeO2catalyst is established in the NH3-SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO2not only increases the surface Ce3+and oxygen vacancy concentration but also provides more sites for capture and dispersion of WOxspecies, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WOxand Cu-doped CeO2is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH3-SCR reaction over WOx/Cu-CeO2may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to the in situDRIFTS.

The sluggish regeneration rate of FeIIand low operating pH still restrict the wider application of classical Fenton process (FeII/H2O2) for practical water treatment. To overcome these challenges, we exploit the Mn–CNH co-catalyst to construct a solid–liquid interfacial Fenton reaction and accelerate the FeIII/FeIIredox cycle at the interface for sustainably generating •OH from H2O2activation. The Mn–CNH co-catalyst exhibits an excellent regeneration rate of FeII(∼65%) and a high tetracycline removal rate (Kobs) of 0.0541 min–1, which is 19.0 times higher than that of the FeII/H2O2system (0.0027 min–1) at a near-neutral pH (pH ≈ 5.8), and it also attains 100% degradation of sulfamethoxazole, rhodamine B, and methyl orange. The cyclic mechanism of FeIII/FeIIis further elucidated in an atomic scale by combining characterizations and density functional theory calculations, including FeaqIIIspecific adsorption and the electron-transfer process. Mn active sites can accumulate electrons from the matrix and adsorb FeaqIIIto form Mn–Fe bonds at the solid–liquid interface, which accelerate electron transfer from Mn–CNH to FeaqIIIand promote the regeneration of FeIIat a wide pH range with a lower energy barrier. The regeneration rate of FeIIin the Mn–CNH/FeII/H2O2system outperforms the benchmark Fenton system and other typical metal nanomaterials, which has great potential to be widely applied in actual environment remediation.