Photocatalytic degradation is a highly efficient, stable and promising technology for water treatment. Developing high-performance photocatalysts is crucial for removing aquatic contaminants. However, traditional zinc oxide (ZnO) photocatalysts are severely restricted by intrinsic drawbacks, such as a wide band gap, fast recombination of photogenerated carriers, and high photocorrosion tendency. Conventional powder catalysts also suffer from difficult recovery and serious secondary pollution. Therefore, developing simple strategies to fabricate high-performance, reusable, and stable ZnO-based photocatalysts is of great scientific and practical importance. In this work, silver-loaded nitrogen-doped ZnO nanoarrays (AgY@NX-ZnO NAs, where X and Y represent the urea and AgNO3 concentrations, respectively) were synthesized on 304 stainless steel sheets (SSS) using a two-step hydrothermal method combined with photoreduction at room temperature. The samples were characterized by XRD, FESEM, XPS, and UV-Vis DRS, and the catalytic mechanism was studied through active species trapping and EPR. Nitrogen doping and Ag loading exhibited a strong synergistic effect, narrowing the band gap, enhancing visible-light absorption, and promoting the separation of photogenerated carriers. The optimal sample (Ag1.5@N4-ZnO NAs) degraded 93.2% of Rhodamine B (RhB) within 180 min, with a reaction rate constant 2.65 times higher than pure ZnO. The main active species were ·O2− and ·OH. This work provides a feasible route to fabricate recyclable and stable stainless steel-based ZnO nanoarray photocatalysts for efficient water purification.

Photocatalytic hydrogen production technology utilizes solar energy to decompose water into hydrogen, helping to alleviate the pressure of energy depletion. Engineering of non-precious metal nanomaterials as cocatalysts can play a significant role in low-cost, sustainable, and large-scale photocatalytic hydrogen production. Herein, MnCdS-Vs/NiCo2S4 (MCSN) Schottky junction nanomaterials with strong electron coupling effect were prepared by a two-step hydrothermal method and successfully applied to a square meter hydrogen evolution device. The optimized MCSN material demonstrated high hydrogen evolution activity of 34.28mmolg-1 h-1, which is 9.34 and 685.60 times higher than that of pure MnCdS-Vs and NiCo2S4, respectively. More importantly, in a square meter (1 m2) flat-plate reactor, MCSN produced H2 evolution approximately 201mmol in 5h, showcasing its potential for large-scale applications. In-situ XPS and DFT calculations demonstrated that MnCdS-Vs interacts with NiCo2S4 to produce a strong electron coupling effect and form a Schottky junction. It promotes the facilitated the directional migration of photogenerated electrons from MnCdS-Vs to NiCo2S4, but also effectively suppressed electron backflow through the Schottky barrier. Furthermore, the abundance of sulfur vacancies enhanced visible light absorption capability, further improving photocatalytic hydrogen evolution performance. This work delves into the role of defect engineering and Schottky junction design in enhancing photocatalytic performance, providing new insights into transitioning photocatalytic hydrogen production technologies from small-scale laboratory experiments to large-scale practical applications.

Developing efficient, stable, low-cost, and earth-rich cocatalysts has been proven to be an effective strategy for achieving highly active semiconductor-based photocatalytic hydrogen evolution from water splitting. Herein, a Schottky junction was rationally fabricated by noble-metal-free metallic tungsten nitride (WN) and sulfur vacancies-rich CdS single crystals (WN/CdS) for competent photocatalytic H-2 evolution. The density functional theory (DFT) calculation results indicated that metallic properties of WN. Systematic investigations reveal that metallic-like WN can be acted as a novel superior electron harvester to rapid capture and transfer photogenerated charges, which can be confirmed by the fluorescence, time-resolved fluorescence spectra (TRPL) and photo-electrochemical characterization and in-situ XPS. And the sulfur vacancies also can act as electron trappers to enhance carrier separation and electron transfer. Thus, the synergistic effect of sulfur vacancies and Schottky junction greatly enhance the photocatalytic H-2 production activity. In addition, the more negative zeta potential of 10 %WN/CdS means the stronger protons adsorption well as promoted hydrogen evolution activity. The maximum photocatalytic H-2 evolution activity of 15.02 mmol g(-1) is achieved over 10 % WN/CdS composite, which is about 2.34 folds of pristine CdS, respectively. Meanwhile, a super photostability over ten consecutive cycles of light irradiation of 100 h is also achieved for photocatalytic hydrogen generation. This work certifies the metallic WN is a promising candidate to construct higher-performance heterostructured photocatalyst for efficient energy conversion.

Application of graphdiyne (GDY) in photocatalysis remains significant challenges. Herein, a 1D/2D S-scheme GDY/ll-AgVO3 heterojunction was successfully constructed by ll-AgVO3 nanorods anchored on GDY nanosheets for high efficiently photocatalytic hydrogen evolution. The GDY nanosheets were fabricated by a convenient mechanical ball milling method. The S-scheme GDY/ll-AgVO3 heterojunction possesses a close interface with oriented built-in electric-field for efficient extraction of photocarriers from the conduction band of ll-AgVO3 to valence band of GDY. The 25 % GDY/ll-AgVO3 exhibited outstanding photocatalytic H2 generation capacity of 14.15 mmol g-1 h-1, which was 17.26 and 11.99 folds greater than that of GDY and ll-AgVO3, respectively. The improved hydrogen evolution efficiency can be given the credit to the establishment of a built-in electric field between GDY and ll-AgVO3, which causes the photogenerated electrons to move directionally following the path of the S-scheme. In addition, GDY showed full spectrum absorption characteristics, and the introduction of GDY into ll-AgVO3 improved the photosensitivity of the catalyst, thus improving the solar energy utilization efficiency. The S-scheme mechanism is certified by in-situ XPS and density functional theory (DFT). The charge density difference of GDY/ll-AgVO3 is further proved the photogenerated electrons of the GDY/ll-AgVO3. This work provided an effectual approach for constructing graphdiyne-based S-scheme heterojunction with oriented builtin electric-field for efficient photocatalysis.

The overall water splitting based on specific photocatalysts is one of the ultimate ways to solve the energy and environmental crisis facing humanity. Sulfide photocatalysts have greater potential in photocatalytic production of solar fuel. However, due to its easy photocorrosion phenomenon, it not effectively driving the water oxidation semi-reaction to produce oxygen, so how to use sulfide photocatalyst to decompose pure water to achieve stoichiometric reaction of H2/O2 production remains a quite challenging task. Herein, sulfur vacancies-rich MnCdS nanoparticles were modified with NiS nanosheets through the hydrothermal derivation method. Different concentration gradients of sulfur-vacancy in MnCdS nanoparticles (MnCdS-Vs-X) with tunable band structures were successful prepared by regulating the concentration of hydrazine hydrate, thus improves the efficiency of light energy utilization and charge separation and the existence of S defects was verified by transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR). The density function theory (DFT) calculation bears out that the draw into of S vacancy adjusted the band structure of MnCdS. Moreover, the successful construction of an S-scheme heterojunction between NiS and MnCdS-Vs-3 has been strongly demonstrated by in -situ XPS and UPS, which promoted interfacial charge separation and further improved the photocatalytic hydrogen evolution efficiency. The as-obtained S-scheme 20 %NiS/MnCdS-Vs-3 heterojunction exhibit excellent visible-light H2 production activity of 4099.55 mu mol g- 1h- 1, 6.75 times higher than pure MnCdS. Most importantly, the excellent and stable photocatalytic overall water splitting activity of H2- 509.70 mu mol g-1h-1/O2-254.90 mu mol g-1h-1 were obtained over 20 % NiS/MnCdS-Vs-3, which further demonstrates the application value of NiS/MnCdS-Vs-3 photocatalysts. This work proposes new ideas for the application of S-vacancies and S-scheme heterojunction in addressing the stability issues associated with sulfide-based photocatalysts in photocatalytic water splitting.

Designing efficient sulfide photocatalysts for the simultaneous split water into H-2 and O-2 continue to be an arduous challenge. Herein, a Zn-vacancy mediated S-scheme MnCdS/ZnS-V-Zn heterojunction derived from MnCdS/MOF-5 via in-situ vulcanization of MOF-5 in a new-fashioned sacrificial reagent of Na2S/NaH2PO2 was fabricated. The presence of Zn vacancy (V-Zn) was certified by TEM, XPS, EPR and PL results, which result in a new defect level in the band structure of ZnS. The S-scheme charge transfer path was established between MnCdS and ZnS-V-Zn by V-Zn vacancies, and the photocorrosion is depressed efficiently and a dramatic rise occurs on photocatalytic performance. The strong electron coupling effect of S-scheme heterojunction mechanism was confirmed via in-situ XPS, SPV, work function, and radicals test by EPR. The band gap and density of state about ZnS-V-Zn and MnCdS are also calculated by the DFT. In HER semi-reaction, the strongest photocatalytic hydrogen generation rate of 20 % MnCdS/ZnS-V-Zn is 394.4 mu mol/h with a splendid apparent quantum efficiency of 16.43 % at 420 nm, and the turnover number (TON) is 98.6. The hydrogen production rate of 20 % MnCdS/ZnS-V-Zn is drastically advanced by 123.25 times in contrast to the unadorned ZnS-V-Zn. And superior photostability is also obtained. Prominently, the high-efficiency and steady photocatalytic overall water splitting rates of 5.7 mu mol/h (H-2) and 3.0 mu mol/h (O-2) were achieved over 20 % MnCdS/ZnS-V-Zn with 1 %wt Pt and 5 %wt Co3O4 nanorod as cocatalysts, and the photocatalytic stability was excellent. This research supplies neoteric insights for designing of highly efficient V-Zn-mediated S-scheme sulfide photocatalysts to achieve pure water overall splitting with superior photocatalytic activity.

The photocatalytic hydrogen evolution ability of catalyst can be effectively improved by constructing suitable heterojunction. The present study involves a new type of carbon-material semiconductor graphdiyne (GDY) was prepared by ball milling assisted reduction elimination reaction, and introduced into metal-rich Ni5P4 nano flowers by hydrothermal method. GDY/Ni5P4 ohm junction was successfully constructed to regulate the electron direction. The C equivalent to C bond in GDY exhibits high reducibility, which is conducive to inhibiting the oxidation of Ni5P4. The unique porous nanoflower-like structure of Ni5P4 enables it to achieve complete contact with solvents, thereby enhancing proton absorption capabilities. The construction of an ohmic junction is confirmed to induce electron transfer from GDY to Ni5P4 through situ XPS characterization, thereby suppressing the recombination of electron-hole pairs in GDY. Among them, 15%GDY/Ni5P4 has the best photocatalytic hydrogen evolution activity of 11713.6 mu mol h-1 g-1, which is about 15 times higher than that of GDY (755.4 mu mol h-1 g-1) and 5 times that of Ni5P4 (2369.6 mu mol h-1 g-1). This work provides a new way to construct ohm junction based on GDY for photocatalytic hydrogen evolution.

Solar photocatalytic hydrolysis of hydrogen is one of the most important ways to solve energy and environmental problems. Rational design and modulation of interfaces in S-scheme heterojunctions still present significant challenges for solar hydrogen production. Herein, a novel 2D/3D hierarchical graphdiyne/CoAl2O4 (GCA) S-scheme heterojunction was successfully constructed by coupling graphdiyne (GDY) nanosheets onto porous CoAl2O4 nanoflowers. GDY was synthesized by a cross-coupling reaction and ultrathin 3D porous CoAl2O4 nanoflowers were transformed from CoAl-LDH. This unique 3D hierarchical porous structure of CoAl2O4 nanoflowers not only provides a larger specific surface area, sufficient active sites and enhanced light harvesting, but also significantly reduces the aggregation of GDY. Notably, hierarchical GCA-15 shows an exceptional photocatalytic hydrogen production rate of 5009.28 mu mol g(-1) h(-1) under visible-light irradiation, which was 4.78 times higher than that of pristine CoAl2O4. This excellent photocatalytic activity can be attributed to the synergistic effect of the formed S-scheme heterojunction between GDY and CoAl2O4 and the 2D/3D hierarchical architecture. In situ irradiated XPS, UPS and DFT unveil the S-scheme electron transfer for GDY/CoAl2O4. The work functions and charge density difference further indicate the electrons transferring from GDY to CoAl2O4. This work provided a simple strategy for designing and constructing hierarchical graphdiyne-based S-scheme heterostructures for photocatalytic hydrogen production.

The design of environmentally friendly and cost-effective S -scheme heterojunctions with robust interfacial interactions is pivotal for enhancing photocatalytic performance and facilitating practical application. In this work, ZnCo 2 O 4 quantum dots (QDs)/graphdiyne (ZCOG) S -scheme heterojunction was synthesized by a simple hydrothermal method. ZnCo 2 O 4 QDs with quantum size effect were prepared by calcination, while graphdiyne (GDY) nanosheets were synthesized by reduction -elimination reaction using CuBr as catalyst. The maximum hydrogen production rate of ZCOG reaches 2472.80 mu mol g -1 h - 1 , which is 30.75 and 10.84 times higher than that of ZnCo 2 O 4 QDs and GDY, respectively. This significantly enhanced photocatalytic activity is attributed to the strongly coupled S -scheme heterojunction between GDY and ZnCo 2 O 4 QDs, which accelerates the photogenerated electron transfer while effectively suppressing the recombination of photogenerated carriers. In addition, the quantum size effect of the ZnCo 2 O 4 QDs leads to an increase in the width of the electronic forbidden band, which enhances the energy of electrons (holes) in the conduction band (valence band). The S -scheme mechanism of ZCOG was revealed by in situ XPS, UPS and TRPL spectroscopy, and the reliability of the conclusions was further verified by DFT calculations. This work provides an efficient strategy for the construction of GDY-based photocatalysts with quantum size effect.

Precisely crafting heterojunctions for efficient charge separation is a major obstacle in the realm of photocatalytic hydrogen evolution. A 0D/2D heterojunction was successfully fabricated by anchoring Ag2S quantum dots (Ag2S QDs) onto graphdiyne (GDY) nanosheets (Ag2S QDs/GDY) using a straightforward physical mixing technique. This unique structure allows for excellent contact between GDY and Ag2S QDs, thereby enhancing the rate of charge transfer. The light absorption capabilities of Ag2S QDs/GDY extend up to 1200 nm, enabling strong absorption of light, including infrared. Through DFT calculations and in-situ XPS analysis, it was demonstrated that incorporating Ag2S QDs onto GDY effectively modulates the electronic structure, promotes an internal electric field, and facilitates directional electron transfer. This directed electron transfer enhances the utilization of electrons by GDY and Ag2S QDs, with the added benefit of Ag2S QDs serving as electron reservoirs for efficient photocatalytic hydrogen evolution. A 7 %Ag2S QDs/GDY composite exhibited impressive efficiency and stable performance in photocatalytic hydrogen evolution (2418 mu mol g-1 h-1), which is much higher than that of GDY and Ag2S QDs. This study conclusively demonstrates that the 0D/2D heterojunction formed by GDY and Ag2S QDs can establish high-quality contact and efficient charge transfer, ultimately enhancing photocatalytic performance.

The design of environmentally friendly and cost-effective S-scheme heterojunctions with robust interfacial interactions is pivotal for enhancing photocatalytic performance and facilitating practical application. In this work, ZnCo2O4 quantum dots (QDs)/graphdiyne (ZCOG) S-scheme heterojunction was synthesized by a simple hydrothermal method. ZnCo2O4 QDs with quantum size effect were prepared by calcination, while graphdiyne (GDY) nanosheets were synthesized by reduction-elimination reaction using CuBr as catalyst. The maximum hydrogen production rate of ZCOG reaches 2472.80 μmol g-1h−1, which is 30.75 and 10.84 times higher than that of ZnCo2O4 QDs and GDY, respectively. This significantly enhanced photocatalytic activity is attributed to the strongly coupled S-scheme heterojunction between GDY and ZnCo2O4 QDs, which accelerates the photogenerated electron transfer while effectively suppressing the recombination of photogenerated carriers. In addition, the quantum size effect of the ZnCo2O4 QDs leads to an increase in the width of the electronic forbidden band, which enhances the energy of electrons (holes) in the conduction band (valence band). The S-scheme mechanism of ZCOG was revealed by in situ XPS, UPS and TRPL spectroscopy, and the reliability of the conclusions was further verified by DFT calculations. This work provides an efficient strategy for the construction of GDY-based photocatalysts with quantum size effect.

Graphdiyne (GDY) is an up-and-coming two-dimensional all-carbon nanostructured material, which fills the long-standing gap in carbon material science and opens up a whole new way for the research of electronic, optical and semiconductor materials. In this work, a 2D-2D S-scheme heterojunction was constructed by 2D GDY coupling with highly crystalline nitrogen defect g-C3N4 nanosheets (GDY/g-C3N4-VN) for efficient photocatalytic overall water splitting. GDY was fabricated by the cross-coupling reaction of hexaethynylbenzene with CuI as catalyst and substrate. And the highly crystalline nitrogen defect porous g-C3N4-VN was fabricated by the alkalimolten salt-assisted method and the existence of N defects was testified by Transmission Electron Microscopy (TEM) and Electron Paramagnetic Resonance (EPR). In addition, the successful construction of S-scheme heterojunction between GDY and crystalline g-C3N4-VN was strongly demonstrated by in situ XPS, Electron Spin Resonance (ESR) and Density Function Theory (DFT) calculations. The construction of GDY/crystalline g-C3N4VN (GNG-X) heterojunctions enhances the charge density and raise detaching efficiency of photogenerated carriers. The excellent and photostable photocatalytic hydrogen evolution activity of 17.87 & mu;mol h-1 was acquired on CNG-25, which increased of 25.23 folds than that of GDY alone. Most importantly, photocatalytic overall water splitting experiments were carried out by loading 3 wt% Co3O4 and 1 wt% Pt as cocatalysts on CNG-25, and the yields of H2 and O2 were obtained as 0.48 & mu;mol h-1 and 0.24 & mu;mol h-1, respectively, which further demonstrated the promising application value of CNG-25 photocatalyst. This work presents a simple strategy for the design and manufacture of novel 2D GDY-based S-scheme heterojunction to enhance photocatalytic activity and achieve overall water splitting.

At 700 °C under 30-sun equivalent irradiation, the Pt–Al–Ce catalyst shows a high DRM efficiency and a near-unity H2/CO ratio. The concentrated sunlight facilitates photocatalytic reactant activation and leads to enhanced catalytic efficiency.

Interfacial solar evaporation holds great potential for water desalination; other sustainable energy resources naturally coexisting with solar energy (e.g., wind and water wave), however, have rarely been exploited to augment solar evaporation, especially in closed conditions. Herein, we developed a novel system that had an interfacial solar evaporator integrated with an angularly vibrating cantilever beam, harnessing both solar and water wave energies when floating on water surfaces for efficient water desalination. Super high evaporation rates of similar to 3.1 and 1.9 kg m(-2) h(-1) under simulated sunlight and vibrations were obtained in open and closed conditions, respectively. In outdoor tests floating on lake water surfaces, the cantilever beam effectively responded to realistic water waves of varying low frequencies and amplitudes, and the system delivered a high condensate collection rate of similar to 1.8 kg m(-2)h(-1). Mechanism studies revealed that the vibrating cantilever beam promoted vapor flow and condensation on selective surfaces. The cantilever beam enabled the direct mechanical energy transfer from water waves to moisture flow without using any electronics, resulting in great systemoperation-maintenance simplicity. This work provides new insights on advancing solar desalination with the simultaneous and rational utilization of multiple sustainable energy resources.

Solar steam generation is an emerging technology of desalination using renewable solar energy, but when treating saline water containing organics, the solar absorber is subject to fouling by low-surface-tension organics. Also, volatile organic compounds (VOCs) present in the source water may evaporate concurrently with water vapor and penetrate into the condensate, causing health concerns to the quality of the distilled water. In this work, we developed a unique water desalination process by integrating solar steam generation with electrochemical degradation to treat saline water containing organics, and strong synergistic effects have been experimentally demonstrated. The process used a dual-functional solar absorber that simultaneously served as a cathode of the electrochemical reactor, whose structural design was optimized by numerical simulation to balance heat transfer and mass transport. Degradation of three model organic pollutants, bisphenol A, phenol (VOC), and humic acid (natural organic matter) was evaluated, and the degradation rate constants were doubled under simulated sunlight compared to that without illumination, likely due to the high local temperature in the electrochemical reactor induced by the photothermal effect and preserved by the rational thermal insulation design. Furthermore, the concentration of VOCs in the condensate was reduced by 20 folds when electrochemical degradation of feed water was applied. In addition, the electrochemical degradation effectively mitigated humic acid fouling on the solar absorber, improving the steam generation rate by 20% after 12 h treatment, compared to the conventional solar evaporation process. Finally, the integrated solar desalination system achieved a thermal efficiency of 92.6% under real sunlight testing.

Cathodic membranes were applied with Fe reagent to enhance the mass transport of electro-Fenton (EF) by means of forced permeation. However, the considerable amount of toxic Fe reagent left in electrolytes may cause secondary pollution. Also, the membranes without active EF catalysts exposed low removal efficiency due to insufficient surface catalytic activity. In this work, an advanced flow-through process without toxic Fe reagent was developed using modified stainless steel (SS) mesh with high catalytic activity. The surface of SS mesh was decorated by catalytically-active FexCo3-xO4 nanoparticles and functionalized carbon nanotubes (CNTs). The synergistic effect between Fe and Co elements enhanced the electro-Fenton efficiency, and the optimal n(Fe): n(Co) ratio was determined at 1:2 from the degradation rate of pollutants and H2O2. The addition of FeCo2O4/CNT enhanced the first-order reaction rate k to 2.60 times on bisphenol A (BPA) removal, and 2.16 times on sulfamethoxazole (SMX) removal, compared to an undecorated mesh. Consequently, 94% of BPA were eliminated after 60 min and 100% of SMX were eliminated after 120 min, respectively, under a low current density of 2.84 mA cm. The total concentration of leached Fe/Co ions into the electrolyte was only around 2.4 μmol L after the treatment.

In situ construction has emerged for fabricating superwetting PVDF membranes with uniform organic coatings and improved resistance to oil fouling, but it remains almost unexplored to apply this strategy to attain durable inorganic coatings and prepare superior antifouling PVDF membranes. Herein, we developed a novel in situ biomineralization method to fabricate superhydrophilic and underwater superoleophobic PVDF-TiO2 membranes with conformal TiO2 coatings on both the top and internal surfaces. An initial flux of 400 L m(-2) h(-1) (LMH) with a final flux of 200 LMH at 2.5 h under 0.1 bar, oil rejection higher than 99.7%, and highly stable cycling per-formance (5 cycles at 130 min each) were achieved on crossflow filtration of surfactant-stabilized oil-in-water emulsions. We used a new "flux map" to make a relatively fair comparison among the reported membranes, which suggested the superior performance of our PVDF-TiO2 membrane. The demonstrated exceptional per-formance was attributed to the low oil adhesion and great hydrophilicity enabled by the durable and super-wetting coatings composed of densely packed TiO2 nanoparticles on the entire membrane, as well as to the relatively smooth top surface with an appropriate surface pore size that alleviate the oils being trapped by the surface structures.

PVDF nanocomposite membranes prepared by the widely used conventional blending-phase inversion method generally suffer from nonuniform distribution and low exposure of additive nanomaterials, resulting in unsatisfactory hydrophilicity and antifouling capability. Herein, we developed a modified blending method that incorporates the water-triggered precipitation (resembles phase inversion) of the nanomaterials into PVDF phase inversion. PVDF-bismuth oxychloride (BiOCl) nanocomposite membranes were prepared by dissolving KCl and Bi(NO3)(3) in the PVDF dope solution to enable the simultaneous precipitation of PVDF and hydrophilic BiOCl in the coagulation bath. Characterizations demonstrated that the nanocomposite membranes are superhydrophilic, mainly attributed to the surface-preferential precipitation of BiOCl. Crossflow filtration results showed that the nanocomposite membrane had a pure water flux of 854 L m(-2) h(-1) bar(-1) (LMHB) and a humic acid separation flux of 780 LMHB, much higher than 377 and 240 LMHB of the plain membrane. For bovine serum albumin (BSA) separation, the nanocomposite membrane achieved a quasi-steady state flux of 370 LMHB and a rejection ratio of similar to 90% during three test cycles. In contrast, the hydrophobic plain membrane was severely fouled by BSA, evidenced by a rejection ratio lower than 40%. We proposed a new mechanism that illustrated the effects of protein-membrane interactions and filtration hydrodynamics that well explained the filtration results. The nanocomposite membrane also possessed a 3-fold higher capacity for Cr (VI) adsorption than the plain membrane. These results suggest that this modified blending-phase inversion method could fabricate nanocomposite membranes with great separation and antifouling capability, and multifunctionality.

Anodic electrocoagulation processes can remove broad varieties of pollutants in industrial wastewater. However, some stubborn contaminants may still remain in effluents after the treatment and cause environmental issues. To further improve the efficiency of pollutant removal, we have coupled electrocatalysis with electrocoagulation and applied an atomic layer deposition (ALD) enabled TiO2 ultrathin overcoating at a nanometer scale on a stainless steel cathode. The electrocatalytic overcoating increased the elimination efficiency of organics and microorganisms, likely due to the electro-generation of adequate reactive oxygen species (ROS). The thickness of TiO2 nanofilm was controlled by the number of ALD cycles, and it was found that nanofilms processed with 50-100 cycles led to the maximum benefit of pollutant removal. By using the novel electrocoagulation-electrocatalysis cell to treat synthetic wastewater, a remarkable removal of 99.92% of E. Coli, 92.1% of suspended solids, 98.3% of heavy metal ions, and 88.8% of methylene blue was observed. This hybrid electrochemical treatment process may have the potential to treat wastewater at a larger scale. (C) 2020 Elsevier Ltd. All rights reserved.

This work investigates photocatalytic reduction of aqueous chlorate by using commercial P25 TiO2 in the presence of hole scavengers under simulated solar light. It compares the photocatalytic ability of P25 TiO2 to reduce chlorate in the presence or absence of a hole scavenger (methanol) with that of bismuth oxyhalides (BiOBr, TiO2-BiOBr, BiOCl, TiO2-BiOCl, and BiOI). Bismuth oxyhalides have more interest as promising photocatalysts because they have a narrow band gap and are more responsive to visible light. However, in this study, P25 TiO2 was a more effective photocatalyst for chlorate reduction in the presence of methanol than bismuth oxyhalides. Also, this study examines the effectiveness of methanol, ethanol, and formate as hole scavengers during chlorate reduction. The presence of methanol enhanced chlorate reduction more than that of formate and ethanol. Finally, this work estimates the impacts of operating parameters such as photocatalyst dose, initial chlorate concentration, solution pH, methanol concentration, and light intensity on chlorate removal and studies the reaction mechanism for chlorate reduction in the system of TiO2/chlorate/methanol (photocatalyst/contaminant/reagent) under simulated solar light. The highest chlorate removal of 97.5% was achieved using 1 g/L of TiO2 with initial chlorate concentration of 0.012 mM and methanol concentration of 2 mM at the pH of 5.4 after 180 min of radiation. The major product of chlorate photoreduction was chloride ion.