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This study developed a facile approach for preparing Ti3+ self-doped TiO2-graphene photocatalyst by a one-step vacuum activation technology involved a relative lower temperature, which could be activated by the visible light owing to the synergistic effect among Ti3+ doping, some new intersurface bonds generation and graphene oxide reduction. Compared with the traditional methods, the vacuum activation involves a low temperature and low-costing, which can achieve the reduction of GO, the self doping of Ti3+ in TiO2 and the loading of TiO2 nanoparticles on GR surface at the same time. These resulting TiO2-graphene composites show the high photodegradation rate of MO, high hydrogen evolution activity and excellent IPCE in the visible light irradiation. The facile vacuum activation method can provide an effective and practical approach to improve the performance of TiO2-graphene and other metal oxides-graphene towards their practical photocatalytic applications. [ABSTRACT FROM AUTHOR]

With the prevalence of green chemistry and the concept of a harmonious society, humans have much greater environmental awareness than ever before. Mesoporous TiO2 and its corresponding photocatalysts can assist the search for a better and more ideal life. In this review, we first briefly introduce the development of various mesoporous materials, after which we discuss the preparation and application of mesoporous TiO2 materials in photocatalysis. When titanium oxide-based mesoporous materials are applied in photocatalysis, they exhibit excellent performance and many advantages in pollutant decomposition and H2 evolution. In addition to the traditional TiO2-based mesoporous materials, novel materials such as Ti-metal organic frameworks are reviewed, as their application in H2 evolution has garnered increasing research interest in recent years. It is evident from literature surveys that these TiO2-based mesoporous photocatalysts have significant potential for use in environmental and energy applications. [ABSTRACT FROM AUTHOR]

To date, the chemical conversion of organic pollutants into value‐added chemical feedstocks rather than CO2 remains a major challenge. Herein, we successfully developed a coupled piezocatalytic and advanced oxidation processes (AOPs) system for achieving the conversion of various organic pollutants to CO. The CO product stems from the specific process in which organics are first oxidized to carbonate through peroxymonosulfate (PMS)‐based AOPs, and then the as‐obtained carbonate is converted into CO by piezoelectric reduction under ultrasonic (US) vibration by using a Co3S4/MoS2 catalyst. Experiments and DFT calculations show that the introduction of Co3S4 not only effectively promotes the transfer and utilization of piezoelectric electrons but also realizes highly selective conversion from carbonate to CO. The Co3S4/MoS2/PMS system has achieved selective generation of CO in actual complex wastewater treatment for the first time, indicating its potential practical applicability. [ABSTRACT FROM AUTHOR]

We have developed a MoS 2 /graphene oxide sponge that can selectively remove ultrafine suspended solids from actual wastewater. We skillfully use the chemical adsorbed CaCO 3 to improve the electropositivity of sponge surface, thus significantly improving its ability to remove electronegative nano-pollutants. In addition, the functionalized sponge can trigger reactions such as Fenton to simultaneously remove organic pollutants and heavy metal ions from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Catalytic hydrogen peroxide (H2O2) generation from oxygen and water enables a sustainable environment to operate in an effective and green energy‐to‐chemical conversion way, which has attracted increasing interest in the fields of energy production and environment treatment. In light of this, tremendous progresses and developments have been made during the past decades in catalytic H2O2 production for pollutant removal from three perspectives including photocatalysis, electrocatalysis or chemical activation. Herein, we critically review the state‐of‐the‐art developments over various procedures of H2O2 generation and its further application, with the existence of photocatalysts, electrocatalysts, and catalysts, respectively. Benefiting from extensively experimental and theoretical investigations, the performance and stability of H2O2 generation and its utilization can be maneuvered by devising catalytic platform based on numerous catalysts with predominant electronic, chemical and physical properties, which endow the catalysts with efficient electrons transportation, abundant active sites, and sufficient oxygen adsorption for H2O2 generation. Furthermore, this review also discusses the formation mechanism of H2O2 by 2e‐ORR and 2e‐WOR, as well as its functional process of activating and removing pollutants, and summarizes the design principles of various catalysts by focusing on the formation of H2O2. We finally highlight the specific challenges and prospects related to the utilization of catalysts and envision the possible future development trends in the fields of pollutant removal. [ABSTRACT FROM AUTHOR]

[Display omitted] Coexistence of radical and nonradical reaction pathways during advanced oxidation processes (AOPs) makes it challenging to obtain flexible regulation of high efficiency and selectivity for the requirement of diverse degradation. Herein, a series of Fe 3 O 4 /MoO x S y samples coupling peroxymonosulfate (PMS) systems enabled the switching of radical and nonradical pathways through the inclusion of defects and adjustment of Mo4+/Mo6+ ratios. The silicon cladding operation introduced defects by disrupting the original lattice of Fe 3 O 4 and MoO x S. Meanwhile, the abundance of defective electrons increased the amount of Mo4+ on the catalyst surface, promoting PMS decomposition with a maximum k value up to 1.530 min−1 and a maximum free radical contribution of 81.33%. The Mo4+/Mo6+ ratio in the catalyst was similarly altered by different Fe contents, and Mo6+ contributed to the production of 1O 2 , allowing the whole system to attain a nonradical species–dominated (68.26%) pathway. The radical species-dominated system has a high chemical oxygen demand (COD) removal rate for actual wastewater treatment. Conversely, the nonradical species-dominated system can considerably improve the biodegradability of wastewater (biochemical oxygen demand (BOD)/COD = 0.997). The tunable hybrid reaction pathways will expand the targeted applications of AOPs. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) are reckoned effective for removing persistent and recalcitrant pollutants by reactive oxygen species (ROSs), including hydroxyl radicals (•OH), sulfate radicals (SO 4 •-), and superoxide radicals (•O 2 -), as well as singlet oxygen (1O 2). In this work, the Mo 2 C quantum dots enriched N-doped graphitic carbon layers (Mo 2 C QDs/NGCLs) were constructed via a facile two-step methodology. Interestingly, the Mo 2 C QDs/NGCLs acted as a highly efficient cocatalyst and/or catalyst simultaneously in AOPs, in particular visible-light-driven (VLD) Fenton and VLD PMS activation. In the hydroxyl radical-based AOPs (•OH-AOPs), it exhibited a remarkable removal efficiency for a range of aromatic organic pollutants, including rhodamine B (RhB) (99.9 %), phenol (90 %), benzophenone-3 (BZP) (83 %), methyl orange (MO) (58 %), methyl blue (MB) (89 %), ibuprofen (IBU) (100 %), and carbamazepine (CBZ) (50 %). Sulfate radicals-based AOPs (SR-AOPs) effectively degrade RhB (72 %), MO (83 %), IBU (70 %), and BZP (100 %). Thus, the present findings confirmed the potential of transition metal carbides for AOP applications and established a solid theoretical and technical basis for further research. [Display omitted] • Mo 2 C QDs/NGCLs were both useful in the VLD-Fenton process (i.e., cocatalyst) and VLD SR-AOPs (i.e., catalyst). • The conversion efficiency of H 2 O 2 is 78.0%, benefiting from the plasmon-hot electrons escaping from Mo 2 C QDs. • Singlet oxygen (1O 2) played a vital role in VLD SR-AOPs. • Mo 2 C QDs/NGCLs retained excellent performance in AOPs. [ABSTRACT FROM AUTHOR]

Ti and carbon co-doped TiO photocatalysts were prepared hydrothermally to introduce the carbon, and followed by simple vacuum activation to achieve the Ti self-doping. The prepared co-doped photocatalysts were characterized by XRD, TEM, UV-Vis absorption spectra, EPR, and XPS. It was found that the co-doped TiO has dispersed nanoparticles and a narrower band-gap compared with the un-doped TiO and single-doped TiO. The experimental results displayed that the coke carbon generated on the surface of co-doped TiO acts as a photosensitizer and has the photosensitization effect under solar light irradiation. Except for the carbon sensitization effect, the Ti self-doping modification has a synergistic effect which is the reason for the effective photo-degradation of methyl orange under simulated solar light irradiation. [ABSTRACT FROM AUTHOR]

Vacuum-activated method was used to prepare Co and Ti co-modified TiO with the intention of enhancing visible light photo-catalytic performance, by expanding the visible light absorption and improving the quantum efficiency of the photo-catalytic reaction. The prepared co-modified catalysts were characterized by XRD, UV-DRS, XPS, EPR, etc. The characterization results indicate that the catalysts have a typical anatase crystalline form, and that some Co are incorporated on the surface of TiO, leading to the formation of Ti and oxygen vacancies. The impurity levels induced by Co and Ti doping are the reason for the enhanced visible light absorption, and the synergistic effect of cobalt, Ti and oxygen vacancies is responsible for the improvement of photo-catalytic activity. [ABSTRACT FROM AUTHOR]

A modified Stöber process using vinyltriethoxysilane as the precursor and in the presence of graphene oxide unprecedentedly leads to the exclusive growth of monodispersed silica nanocrystals (SiO 2 NCs) (ca. 3–4 nm) at room-temperature on single-layer graphene sheet with a high deposition density (ca. 10 16 /m 2 ), where graphene oxide is simultaneously reduced by ammonia. Well-resolved lattice fringes with the spacing of 0.19 nm demonstrate the excellent crystallinity of SiO 2 NC, which has an absorption band in the range of 200–400 nm. The anchoring of vinyl-silanols on graphene oxide through Si O C oxo-bridging and the π – π interaction between double bonds of vinyl-silanols and graphene oxide co-direct the orderly growth of SiO 2 NC nuclei on graphene. Compared with isolate and physically mixed SiO 2 and graphene, the composite has decreased impedance and 4.5 times improved photocurrent, which also shows extraordinarily high photocatalytic activity toward the degradation of organic pollutant. [ABSTRACT FROM AUTHOR]

The universal limit on the pH conditions is disturbing peroxymonosulfate (PMS)‐triggered high‐valent iron‐oxo systems in environmental applications. Here, we propose for the first time the construction of a neutral microenvironment on the surface of Zn−Fe layered double hydroxide (ZnFe‐LDH) by using the amphoteric properties of zinc hydroxide, which continuously generates ≡FeIV=O over a wide pH range of 3.0–11.0 in activating PMS. The ≡Zn(OH)2 moiety offers a neutral microenvironment at the phase interface, which mitigates the self‐decomposition of ≡FeIV=O by protons and the hydrolysis reaction of iron by hydroxyl groups, which is supported by the Mossbauer spectra, density functional theory calculations and designed experiments. Consequently, ZnFe‐LDH/PMS can satisfy the stability in long‐term experiments, selectivity under conditions with high salinity or natural organic matter and efficient treatment of actual wastewater. [ABSTRACT FROM AUTHOR]

Vacuum activation method was used to modify TiO to produce highly air stable V and Ti co-doped TiO. The physicochemical properties of the catalysts were studied by a series of characterizations. The low valence Ti and V states were formed by vacuum activation and vanadium doping formed new impurity bands between CB and VB of TiO, which narrowed the band gap and enhanced the absorption of visible light. Also, the V/V and Ti/Ti cations could reduce the e/h pair recombination rate to give high quantum efficiency. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: In this study, ternary P25/GO/Pt hybrid photocatalysts are prepared in different orders, using Degussa's TiO2 (P25), graphene oxide (GO), chloroplatinic acid as precursor. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). This work is first time to compare the hydrogen production of the ternary P25/GO/Pt hybrid photocatalysts prepared in different orders. We focus on studying the introduction of GO and find that the quantity of introduced GO and electronic transfer path play an important role in photocatalytic activity on ternary P25/GO/Pt hybrid catalysts. When the proper Pt particle loaded on the flat surface of GO which was 0.5wt% of P25, the highest H2 evolution was obtained. [Copyright &y& Elsevier]

A novel defect-induced inorganic photoluminescence powder silica (CSI-SiO2) nanomaterial was successfully synthesized via a facile method, where Cs+ was doped into SiO2 by ion exchange, and oxygen vacancy defects were produced during a vacuum calcination treatment at high temperature. CSI-SiO2 was characterized by scanning electron microscopy, X-ray diffraction and photoluminescence spectroscopy. The result showed that CSI-SiO2 contained merely three elements including Cs, Si, and O. Compared with conventional fluorescent materials, the preparation method of fluorescent material (CSI-SiO2) didn't need the precursor of heavy metals, rare earth metals and other harm contents, making it capable to be an environmentally friendly candidate. More importantly, CSI-SiO2 exhibited hyper-stable photoluminescence performance in harsh conditions including strong acidic, weak alkaline, moist and high temperature conditions, which can be applied in security marking. The mechanism diagram of material CSI-SiO2 for defect-induced photoluminescence. [ABSTRACT FROM AUTHOR]

Hollow metal-organic frameworks (MOFs) and their derivatives have attracted more and more attention due to their high specific surface area and perfect morphological structure, which determine their large potential application in energy storage and catalysis fields. However, few researchers have carried out further modification on the outer shell of hollow MOFs, such as the perforation modification, which will endow hollow nanomaterials derived from MOFs with multifunctionality. In this paper, hollow MOFs of MIL-53(Fe) with perforated outer surface are successfully synthesized by using SiO 2 nanospheres as the template via a self-assembly process induced by the coordination polymerization. The tightly packed mesopore structure makes the carbon outer shell of MOFs thinner, thus realizing the in-situ transformation from MOFs to hollow Fe 3 O 4 /carbon, which exhibits perfect capacity approaching 1270 mA h g−1 even after 200 cycles at 0.1 A g−1, as an anode material in lithium ion batteries (LIBs) application. This research provides a new strategy for the design and preparation of MOFs and their derivatives with multifunctionality for the energy applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A hybrid catalyst of H-form titania tanotube-carbon dot (HTNT-CD) was developed. • HTNT-CD is efficient for photocatalytic synthesis of H 2 O 2. • The solar-to- H 2 O 2 apparent energy conversion efficiency could reach 5.2%. • The protons accelerate the half reaction of O 2 reduction to form H 2 O 2. Abstract Photocatalytic synthesis of hydrogen peroxide (H 2 O 2) from water and oxygen is an alternative route for clean energy storage and chemical synthesis, but still having problems with insufficient H 2 O 2 productivity and solar-to-chemical energy conversion efficiency. Herein, we reported a hybrid catalyst of proton-form titania nanotube with carbon dot (HTNT-CD) that is highly efficient for the production of H 2 O 2 under visible-light irradiation (λ > 420 nm, H 2 O 2 productivity at 3.42 mmol g cat −1⋅h−1), outperforming the titania catalysts containing noble metals and the carbon nitride catalysts reported previously. Multiple studies demonstrate that the protons on the HTNT-CD are crucial for the production of H 2 O 2 by efficiently accelerating the half reaction of molecular oxygen reduction to form H 2 O 2 , and effectively hindering H 2 O 2 decomposition under the irradiation conditions. This HTNT-CD catalyst gives solar-to-H 2 O 2 apparent energy conversion efficiency at 5.2%, which is even 4.9 times of that (1.06%) over the catalyst derived from commercial P25 and CDs. More importantly, the HTNT-CD is stable, giving high H 2 O 2 productivity in the continuous recycle tests. [ABSTRACT FROM AUTHOR]

Transition-metal phosphides (TMPs) have emerged as anode materials for lithium-ion batteries owing to their high theoretical capacity and stable cyclability. Moreover, by increasing the content of P in TMPs, their lithium storage performance can be further improved. However, the decreased electrical conductivity caused by continuous increment of the P doping into metal and the large volume change during the lithiation/delithiation process limit the electrical energy storage applications of such materials. The combination of the advantages of graphene and a hollow structure is regarded as an approach to solve these issues. In this work, CoP nanocages wrapped by reduced graphene oxide (CoP@RGO) were fabricated via a template-based method followed by a low-temperature phosphating process. Such a unique structure can not only accommodate the volume change during the lithiation/delithiation process but also improve the electric conductivity of the CoP nanocages. The obtained CoP@RGO nanocages exhibited remarkable stable capacity of 546.6 mA h g−1 at current density of 100 mA g−1 over 500 cycles (or 460.4 mA h g−1 at current density of 500 mA g−1 over 500 cycles). [ABSTRACT FROM AUTHOR]

Highly crystalline graphitic carbon nitride (g-C 3 N 4 ) possesses the high separation efficiency of photogenerated electron-hole pairs owing to the significantly decreased intralayer hydrogen bonds, which leads to drastic improvement of photocatalytic activity. However, the preparation of such g-C 3 N 4 material remains a challenge by a simple and economic thermal-treatment in a furnace. Herein, we report a novel and effective strategy for high-yield synthesis of extremely active crystalline carbon nitride nanosheets (CCNNSs) by two-step calcination without the assistance of any additive or salt intercalation. As expected, the as-prepared CCNNSs exhibit a remarkably high hydrogen evolution rate of 9577.6 μmol h −1  g −1 under simulated solar light irradiation, which is 15.5 times than that of bulk g-C 3 N 4 , as well as higher than most of the reported crystalline g-C 3 N 4 . Moreover, a highly apparent quantum efficiency of 9.01% at 420 nm for hydrogen evolution can be achieved, which is also superior to the reported crystalline g-C 3 N 4 . Such two-step calcination approach not only provides an economical way to effectively regulate the crystallinity of bulk g-C 3 N 4 , but also achieves the preparation of CCNNSs with high yield. Our research opens up a new window to self-modification and fabrication of highly active metal-free photocatalysts for solar light-driven hydrogen production. [ABSTRACT FROM AUTHOR]

It remains challenging to process the industrial wastewater of high consistence of organic pollutants and difficult decomposition of heavy metal ions. In this study, we develop a functional nanocomposite hydrogel with a highly photocatalytic Fenton reaction activity for the degradation of organic pollutants and adsorption for the heavy metal ions. The hydrogel is made up of Fe 3 O 4 nanoparticles, reduced graphene oxide (RGO) and polyacrylamide (PAM), which is prepared by a two-step chemical synthetic method, and exhibits the outstanding mechanical strength, Photo-Fenton activity, adsorptive property and reversibility. For the degradation of organic dyes, the Fe 3 O 4 /RGO/PAM hydrogel can degrade the 20 mg/L Rhodamine B (RhB) for 90% within 60 min under visible light irradiation, and even after 10 times cycle test, the degradation rate for RhB still keeps at 90%. Meanwhile, it can degrade the actual sewage of fine chemical wastewater, whose COD (Chemical Oxygen Demand) decreases from 10400 to 2840 mg/L after one hour’s visible irradiation. For the synchronous removal of organic pollutants and heavy metal ions over hydrogel, the degradation data of 20 mg/L RhB can be up to 90% with 20 min under visible light irradiation, and the removal rate of various metal ions can reach up to 34.8%–66.3% after continual two days’ adsorption. This study provides a new pathway to process the industrial wastewater of high consistence and difficult decomposition. [ABSTRACT FROM AUTHOR]

Modification of brookite titanium dioxide (TiO) for the treatment of typical pollutants is a great challenge, owing to its poor chemical stability and the difficulty involved in obtaining it. In this paper, we report a facile method to prepare Fe modified brookite TiO. The Fe modified brookite TiO catalysts exhibit enhanced absorption in visible light region and efficient separation of photo-generated electrons and holes. Meanwhile, we investigate the effect of the modified contents of Fe on the photocatalytic activity, and the optimum Fe content is obtained at 2 wt% that shows the highest photocatalytic activity for the degradation of Rhodamine B both under UV and visible light irradiation. The traps induced by the Fe doping have been well studied here, which are expected to contribute to the narrowing of the band gap of brookite and the separation of electrons and holes. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A series of carbon-doped titanium dioxide (C-TiO 2 ) nanocrystals were hydrothermally synthesized using Ti(SO 4 ) 2 and glucose as titania and carbon resources for 12–48 h. Transmission electron microscopy and X-ray powder diffraction analyses demonstrate that these C-TiO 2 nanocrystals are well crystallized and exhibit better particle dispersity than non-doped TiO 2 . Compared with pure TiO 2 , all dye-sensitized solar cells (DSSCs) assembled from C-TiO 2 nanocrystals exhibited improved short circuit current and open circuit voltage. A highest energy conversion efficiency (6.9%) was achieved on C-TiO 2 synthesized for 24 h, with a significant improvement of 35.3%. The enhancement was attributed to both the less charge recombination and the negative shifting of the flat band potential as demonstrated by dye-adsorption analysis, photoluminescence and electron lifetime measurements. [ABSTRACT FROM AUTHOR]

[Display omitted] • Transition metal phosphides (MPs) are attractive heterogeneous Fenton-like catalysts. • Metalloid structure and superior conductivity of MPs favor interfacial catalysis. • Metal redox cycling are accelerated by electron supply from reductive phosphide. • Electron- and photo-Fenton processes assist Fenton-like oxidation of pollutants. The development of low cost, efficient materials for heterogeneous Fenton-like catalysis continues to be an active area of research for water treatment. Over the past few years, transition metal phosphides (MPs) have witnessed rapid development and their application fields are rapidly expanding from photocatalytic water splitting to advanced oxidation. The unique metalloid structure and superior electron conductivity of these materials endow them with significantly raised catalytic activity for interfacial reactions relative to their corresponding oxyhydroxides, although the existing studies are still at laboratory scale and the insufficient mechanical study and material engineering are still key barriers to practical application. In this review, we summarize the progress in MPs-based heterogenous Fenton-like processes by introducing the fundamentals and catalytic performances of various MPs for activation of hydrogen peroxide, persulfate or dioxygen, both under normal and electro-assisted or photo-assisted scenarios. In addition, we discuss the remaining challenges for their practical water treatment application and offer perspectives on possible future research directions. [ABSTRACT FROM AUTHOR]

We employ a one-step vacuum activation method to obtain Ti 3+ and N co-doped TiO 2 photocatalysts with high reactivity under visible light. The prepared photocatalysts were characterized with XRD, UV–vis absorption spectra, XPS, EPR, and BET. The characterization results indicate that the co-doped photocatalysts have a relative small crystallite size and high surface area. After the vacuum activation, the Ti 3+ is generated in the bulk of TiO 2 and the nitrogen is transferred from the surface to the lattice of TiO 2 . The vacuum activated TiO 2 catalysts have revealed an improvement over pure TiO 2 under visible light irradiation both in optical absorption and photocatalytic activity. It suggests that vacuum activated procedure can not only produce Ti 3+ in the bulk of TiO 2 to improve its visible-light activity but also can be a good method to further introduce some anionic species for the doping such as nitrogen element which is good for band-gap narrowing. In addition, the enhanced visible-light photocatalytic activity of the catalyst does not rely on the sacrifice of the photocatalytic activity under UV-light irradiation. [ABSTRACT FROM AUTHOR]

In this paper, we report a facile Stöber-like method to prepare the ultra-dispersed Fe 3 O 4 nanoparticles (3–8 nm) on the reduced graphene oxide (RGO) sheet by using Iron (III) acetylacetonate (Fe(acac) 3 ) as the iron precursor. This strategy provides a facile and environmentally friendly method for the large-scale synthesis of Fe 3 O 4 /RGO without any additional reductants and organic surfactants. The prepared hybrid materials are used as the Photo-Fenton catalyst to display a high and stable performance for the recyclable degradation of methyl orange pollutant, owing to the high conversion efficiency of Fe 3+ /Fe 2+ and the magnetic property of Fe 3 O 4 . Furthermore, the hybrids also show superior lithium storage performance with large reversible capacity, excellent cyclic performance (624 mAh g −1 for up to 50 charge/discharge cycles at a current density of 0.1 A g −1 ), and good rate capability (624 and 415 mAh g −1 at 0.1 and 2.4 A g −1 , respectively) as an anode material, owing to its superior electrical conductivity, high surface area, excellent electrode homogeneity and dispersity. We believe that the involved Stöber-like pre-treatment method can be further extended to prepare various metal oxides/graphene composites with promising applications across a broad range of catalysis, sensors, supercapacitors, and batteries. [ABSTRACT FROM AUTHOR]

Cu is widely used to prepare high-value products in photocatalytic CO 2 reduction reaction (CO2PR). The valence state of transition metals usually has a great impact on the catalytic process. However, the research on Cu valence in CO2PR is lack for its complex valence change. In current work, Cu x /P25 with stable Cu valence composition in CO2PR is prepared. The results show that Cu is composed of Cu0 and Cu 2 O, and their proportions change regularly as Cu loading changing, which are linearly related to the selectivity of the corresponding products of CO2PR. Combined with thermodynamic and kinetic analysis, the CO adsorption and activation on the surface of Cu0 and Cu 2 O are considered to be the key to determine the product of CO2PR, which is further confirmed by DFT calculation. Cu0 and Cu 2 O are proved to be active site of producing CH 4 and CO, respectively. In this case, a reference for the study of highly selectivity Cu based photocatalysts is provided. In current work, Cu x /P25 with stable Cu valence composition in CO2PR is prepared. Cu is composed of Cu0 and Cu 2 O, and their proportions change regularly as Cu loading changing, which are linearly related to the selectivity of the corresponding products of CO2PR. Combined with thermodynamic and kinetic analysis, the CO adsorption and activation on the surface of Cu0 and Cu 2 O are considered to be the key to determine the product of CO2PR, which is further confirmed by DFT calculation. Cu0 and Cu 2 O are proved to be active site of producing CH 4 and CO, respectively. In this case, a reference for the study of highly selectivity Cu based photocatalysts is provided. [Display omitted] • The Cu x /P25 with stable proportion of different valence Cu components in the process of CO2PR were designed. • The role of each valence Cu component in the Cu x /P25 was studied in the CO2PR. • It is confirmed that Cu0 is the active site of producing CH 4 and Cu 2 O is the active site of CO production. • The adsorption of Cu0 and Cu 2 O on CO is the key to determine the final product on the corresponding surface. • This study provides a reference for the study of highly selective Cu-based photocatalysts. [ABSTRACT FROM AUTHOR]

A series of nitrogen/Ti 3+ co-doped titanium dioxides (N–TiO 2− x ) were successfully synthesized through a calcination–vacuum activation method by using low-cost ammonium hydroxide as the nitrogen source. Interestingly, the nitrogen could be further doped into TiO 2 lattice via the substitution of oxygen vacancies after the vacuum activation treatment. The as-prepared catalysts exhibited high visible light activity by improved substitution of nitrogen concentration with no affecting the UV-light photocatalytic activities. The samples were characterized by the XRD, UV–vis DRS, ESR, XPS and TEM analyzes. When the temperature of vacuum activation was 300 °C, N–TiO 2− x catalyst showed the highest photocatalytic activity for the degradation of methyl orange (MO) under the visible light irradiation. The increase in the visible-light photocatalytic activity was attributed to the synergistic effect between Ti 3+ and nitrogen doping, which contributed to the increase of absorption in the visible light region. It can be claimed that N–TiO 2− x (300 °C-3 h) contained the highest concentration of Ti 3+ . [ABSTRACT FROM AUTHOR]

In this paper, p–n type CuInS 2 /TiO 2 particles were prepared in ethylenediamine by the solvothermal method. The microstructural properties of the synthesized p–n type catalysts were characterized by X-ray diffraction (XRD) in order to confirm the existence of crystalline CuInS 2 on the surface of TiO 2 , which was also confirmed by X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy (TEM) images provided the detailed morphological properties about the CuInS 2 /TiO 2 heterostructure. UV–vis diffuse reflectance spectroscopy (UV–vis DRS) was used to investigate the optical properties of the CuInS 2 /TiO 2 particles. The DRS results indicated that both the p–n type structure and CuInS 2 acting as a sensitizer can enhance significantly the absorption of UV and visible light. The photocatalytic activities of the CuInS 2 /TiO 2 particles were evaluated by hydrogen evolution reactions using Xe-lamp irradiation as a simulated solar light source. The greatly enhanced photocatalytic activity of hydrogen evolution under simulated solar light is about ~7 fold higher than that of pure commercial TiO 2 (Degussa P25). [ABSTRACT FROM AUTHOR]

A series of mesoporous TiO 2 spheres of nanosized crystals with high monodispersity and dimensional homogeneity are synthesized by a simple reflux method. In order to improve the visible light response and to further narrow the band bap of TiO 2 sphere, nitrogen is used as the dopant in a hydrothermal method. Different from the traditional nitrogen doping in TiO 2 solid sphere, the nitrogen is uniformly distributed from bulk to the surface of mesoporous TiO 2 sphere, which is beneficial to the generation of the successive energy bands inside the TiO 2 band gap. Interestingly, the XPS results indicate that the nitrogen doping concentration could reach 1.31% (only 0.17% for nitrogen doped solid TiO 2 sphere), owing to the homogeneous doping in the mesoporous TiO 2 spheres. The nitrogen doped TiO 2 spheres exhibit such excellent characteristics as high specific area, relatively small particle size, pure anatase phase and excellent UV–vis absorption capacity in the range of 400–800 nm, which are all beneficial to the photo-degradation of Rhodamine B under the visible light irradiation. The high photocatalytic activity could be ascribed to the homogeneous nitrogen doping on the deep adjustment of energy band of TiO 2 sphere from the bulk to the surface. [ABSTRACT FROM AUTHOR]

Abstract: Cu2O/TiO2 nanoparticles were prepared by solvothermal method, which formed the heterostructure of Cu2O/TiO2. Due to the heterostructure, the H2 evolution rate under simulated solar irradiation was increasingly promoted. Meanwhile a certain amount of Cu particles which were confirmed by Transmission Electro Microscopy (TEM) and X-Ray Photoelectron Spectroscopy (XPS), formed on the surface of Cu2O/TiO2, and the photoactivity was accordingly further enhanced. The stabilized activity was maintained after many times irradiation. It is interesting that after a few hours irradiation the amount of Cu particles on the surface kept unchanged in the presence of Cu2O and TiO2. The Cu particles that formed during hydrogen generation reaction play a key role in the further enhancement of the hydrogen production activity. In this study, it is the first time to study the details on the formation of the stable ternary structure under simulated solar irradiation and their synergistic effect on the photoactivity of the water splitting. [Copyright &y& Elsevier]

[Display omitted] • Ni doped few-layer ZnIn 2 S 4 nanosheets with preferred Zn occupation were prepared. • Ni selective incorporation endowed ZnIn 2 S 4 with improved charge separation efficiency. • Ni selective incorporation contributed to promoting the H 2 desorption from S sites. • Ni-ZnIn 2 S 4 showed an enhanced photocatalytic hydrogen evolution activity relative to bare ZnIn 2 S 4. Major challenges of realization of all-in-one hydrogen-evolving photocatalysts are the relatively poor charge separation efficiency and unfavorable hydrogen desorption properties owing to the strong correlation between the catalytic site and adsorbed H. Herein, an example of Ni doped few-layer ZnIn 2 S 4 nanosheets (Ni-ZnIn 2 S 4) is carried out to deeply understand the role of Ni dopant in tailoring the charge separation efficiency and weakening the bond energy between electronegative S sites and adsorbed H (S-H ads). Our theoretical calculations demonstrate that Ni ions preferentially incorporates into tetrahedral Zn sites rather than tetrahedral/octahedral In sites, which endows Ni-ZnIn 2 S 4 with improved electronic conductivity and more delocalized charge carriers involved in hydrogen evolution reaction (HER). More importantly, Ni dopants can be capable of exquisitely altering the electronic structure of S sites, leading to a balanced hydrogen adsorption and desorption ability. Consequently, the as-prepared few-layer Ni-ZnIn 2 S 4 nanosheets enable long-lived photo-excited electrons and enhanced photocatalytic HER performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe2+/PMS photo-Fenton-like performance could be improved by IO WO 3 cocatalyst. • 1O 2 is proved main ROS in this heterogeneous co-catalytic photo-Fenton-like process. • 1O 2 can be directly converted from SO 4 − and O 2 − radicals without OH intermediate. • The efficient photogenerated carrier catalyst can improve photo-Fenton activity. Singlet oxygen (1O 2) as an important reactive oxygen species (ROS) has broad application prospects in the fields of organic synthesis, cell repair, environmental remediation et al. However, the mechanism of the 1O 2 formation in the Fe2+/PMS Fenton-like system, which is directly transformed from O 2 − or generated by OH as an intermediate, is still a mystery. Herein, we designed an inverse opal WO 3 (IO WO 3) co-catalytic photo-Fenton-like system, which can finish RhB (20 mg·L−1) degradation within 6 min. And the optimal condition of pH, light intensity, FeSO 4 ·7H 2 O dosage, PMS dosage, cocatalyst dosage were also explored in this work. The high-efficiency photogenerated long lifetime charge carriers produced by IO WO 3 cocatalyst under photocatalytic process can directly make a conversion from SO 4 −and O 2 − to 1O 2 without OH intermediate in the solution. Furthermore, the IO WO 3 cocatalyst addition can improve the reduction of Fe3+/Fe2+ ions to enhance activation of PMS molecule. As for the interconnected periodic macroporous framework of inverse opal WO 3 would help to improve mass transfer and light harvest in the photo-Fenton-like process. This facile synthesized material with recyclable and stable co-catalytic activity for the contaminant remediation, and the selective generation of 1O 2 in the Fe2+/PMS process, will highlight its huge application in environmental potential. [ABSTRACT FROM AUTHOR]

• Bimetallic MoFe/TiO 2 nanospheres were constructed via a two-step methodology. • Both photo-generated electrons and transition metallic redox couples play vital roles in the PMS activation. • SO 4 −, OH, and SO 5 − participate in the transformation and generation of singlet oxygen (1O 2). • DFT calculation revealed that Mo sites on the bimetallic MoFe (110) facet are more favorable to adsorb PMS molecules. • Electrons transferring from the Mo to Fe atoms facilitated the adsorption of the negatively charged HSO 5 − anions. Sulfate-radical (SO 4 −) based Advanced Oxidation Process (SR-AOP), which is mainly generated from peroxymonosulfate (PMS) activation, is an excellent route for water treatment. Bimetallic nanoparticles have been widely applied in electronic, chemical, biological, and mechanical fields, etc.; however, few researchers have attempted to adopt bimetallic nanoparticles in environmental remediation. Further, in recent years, element molybdenum (Mo) has addressed much more environmental field attention than ever. Although singlet oxygen (1O 2) generated commonly in SR-AOPs, its generation mechanism remains controversial. Hence, in this work, bimetallic MoFe/TiO 2 nanospheres were rationally constructed via a facile two-step methodology. Undoubtedly, it exhibited superior performance for the degradation of organic pollutants (e.g., rhodamine, phenol, 4-chlorophenol and sulfadiazine) irradiated by simulated solar light. Both photo-generated electrons and transition metallic redox couples (i.e., Mo6+/Mo4+, Fe3+/Fe2+ and Mo4+/Fe3+) play vital roles in the PMS activation. Distinct from conventional SR-AOPs, sulfate radicals (SO 4 −), hydroxyl radicals (OH) and peroxymonosulfate radicals (SO 5 −) indeed participate in the transformation and generation of singlet oxygen (1O 2). With the combination of DFT calculation, the Mo sites on the bimetallic MoFe (110) facet are more favorable to adsorb PMS molecules, then followed by the dissociation of PMS progressing on the Mo sites. Electrons transferring from the Mo atoms to the Fe atoms facilitated the adsorption of the negatively charged HSO 5 - anions, resulting in enhanced PMS activation efficiency. Considering its novelty and generation mechanism, this work highlights the mechanism of 1O 2 generation from PMS reduction and oxidation simultaneously and furnishes theoretical support for further relevant studies. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) have been widely accepted as an efficient and promising strategy for treating organic pollutants, is mainly dominated by hydroxyl radicals (•OH); however, its further practical application has been hindered by its low decomposition rate of H 2 O 2. Hence, for the first time, we propose an eco-friendly and facile synthesis methodology synthesize water-soluble Co 9 S 8 quantum dots (QDs) derived from commercial cobalt disulfide (CoS 2), which can serve as excellent co-catalysts to dramatically enhance the decomposition rate of H 2 O 2. It is demonstrated that the conversion rate of H 2 O 2 into •OH is ca. 80.02% promoted by Co 9 S 8 QDs, whereas the conventional Fenton process is ca. 34.9%. The result shows that unsaturated edged S atoms on the surface of Co 9 S 8 play a pivotal role in this enhancement, where the number of protons will react with sulfur atoms to form H 2 S and expose reductive metallic active sites to accelerate the Fe3+/Fe2+ conversion. In addition, to tackle the issue for difficult recovery of liquid quantum dots, the magnetic Co 9 S 8 QDs/Fe 3 O 4 nanoparticles are particularly synthesized, which show excellent performance for degradation of 20 mg/L Rhodamine B (RhB). Moreover, the TOC degradation rate can remain stable at 80% even after five cycles. It is expected that this work will provide a new pathway of thinking in the Fenton process and impulse the usage of liquid quantum dots in practical AOPs application. Image 1 • The water-soluble Co9S8 quantum dots derived from commercial CoS 2 were synthesized. • Co9S8 is served as co-catalysts to dramatically enhance the decomposition efficiency of H2O2. • Unsaturated S atoms on the surface of Co9S8 play a pivotal role for enhancement. • Magnetic Co9S8 QDs/Fe3O4 show excellent degradation performance and recycled capacity. [ABSTRACT FROM AUTHOR]

• Z-scheme photo-Fenton system was synthesized for efficiency synchronous REDOX. • The high Fe2+/ Fe3+ ratio of Z-scheme system promotes the decomposition of H 2 O 2. • High concentration of electron promotes the reduction of various metal ions. • Z-scheme system can inhibit the formation of high toxic intermediates. • Z-scheme photo-Fenton system showed long-term stability and broad-spectrum activity. The applications of traditional photo-Fenton reaction are mainly limited by the low photo generated electron concentration, resulting in the low Fe3+/Fe2+ conversion efficiency and low concentration of reactive oxygen specious (ROS). In this study, a mesoporous TiO 2 single crystal decorated by platinum (Pt) nanoparticles and molybdenum disulfide (MoS 2) hybrid Z-scheme system (Pt-MSCs@MoS 2) is successfully synthesized for efficiency synchronous REDOX. The construction of Z-scheme composite leads to the consumption of photo-generated hole (h+) and prolongs the lifetime of the electrons (e−) of MoS 2 , so as to ensure that the MoS 2 is exposed with Mo4+ active sites and exhibits high efficiency for Fe2+/Fe3+ cycling. The high Fe2+/ Fe3+ ratio of Z-scheme photo-Fenton system is conducive to the decomposition of hydrogen peroxide (H 2 O 2) to produce more ·OH. High concentration of photo-generated e− with high reduction potential is conducive to the reduction and recovery of various metal ions, such as Cr6+, Ag+, Cu+ and Ni+. Therefore, the Z-scheme photo-Fenton system shows strong synchronous REDOX performance for removal of different emerging organic contaminants and recovery of different metal ions. The reasonable mechanism of Z-scheme photo-Fenton system and oxidation pathway of carbamazepine (CBZ) were investigated by experimental analysis and molecular orbital calculation. The toxicities of CBZ and its oxidation intermediates in Z-scheme photo-Fenton systems were compared by Toxicity Estimation Software (T.E.S.T.) based on quantitative structure-activity relationship (QSAR). This Z-scheme provides a high efficiency synchronous REDOX strategy for wastewater treatment. [ABSTRACT FROM AUTHOR]

• Three-dimensional catalyst was prepared by the reaction of CoOOH/GO with acrylamide monomer. • Co2+ could activate PMS to effectively remove various organic pollutants. • Hydrogel limited the dissolution of Cox+ and reduced the secondary pollution. • The degradation system achieved the automatic treatment of wastewater under laboratory conditions. Sulfate radical (SO 4 −) produced by peroxymonosulfate (PMS) activation has been extensively studied due to the excellent oxidation ability in organic pollutants decomposition. PMS can be activated by various transition metal ions to generate active radicals, and Co2+ shows the best activation ability for PMS. However, the secondary pollution of cobalt ions (Cox+) limits the application of Co2+/PMS system. In this work, the three-dimensional (3D) cobalt hydroxide (CoOOH)/graphene oxide (GO) hydrogel was prepared as a catalyst through graft polymerization reaction between CoOOH/GO composite and acrylamide monomer. The 3D composite hydrogel has multiple advantages in wastewater treatment application. It could be packed into the degradation columns of the equipment to achieve automatic treatment of wastewater under laboratory conditions, which is helpful to promote the large-scale treatment of industrial wastewater. The Co2+ loaded inside 3D hydrogel could efficiently activate PMS to generate active species. The quencher experiments and electronic paramagnetic resonance (EPR) spectra proved that SO 4 − and 1O 2 are the main oxidation species in CoOOH/GO hydrogel/PMS system for the remediation of organic pollutants, including rhodamine B, phenol, p-chlorophenol, bisphenol A, sulfadiazine, norfloxacin, and tetracycline hydrochloride. The existing GO and hydrogel could effectively inhibit the dissolution of Cox+, reduce the secondary pollution, and prolong the service time of the catalyst, which showed good catalytic activity even after ten cycles. Under the flow reaction system, the mineralization rate of organic molecules such as sulfadiazine can reach more than 40% after two cyclic reactions. The dissolution of Cox+ was measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), which met the national standards after the second cyclic test. In the automated process, the dissolved Cox+ can also be used in the next cycles to further promote the decomposition of PMS. In a word, this work provides a new way for the industrial application of Cox+/PMS system for the remediation of wastewater. [ABSTRACT FROM AUTHOR]

• Ultrathin g-C 3 N 4 nanosheets with hierarchical pores and desirable energy band for H 2 O 2 production has been prepared. • A high H 2 O 2 production rate of 1083 μmol g−1 h−1 has been achieved. • The optimization of energy band via P doping changed the reaction route for H 2 O 2 production. • Unique morphology acts in synergy with suitable energy band to enhance the H 2 O 2 production. H 2 O 2 production through photocatalysis has been considered as a sustainable technique. Here, we report ultrathin g-C 3 N 4 nanosheets with hierarchical pores and desirable energy band for high-efficiency photocatalytic H 2 O 2 production. The resultant catalyst showing an ultra-high H 2 O 2 production rate of 1083 μmol g−1 h−1, which is about seven times higher than that of bulk g-C 3 N 4 and represents one of the most active photocatalysts for H 2 O 2 production. DFT calculation and experimental studies revealed that the suitable energy band structure achieved by a phosphorus doping in g-C 3 N 4 leading to the efficient yielding two-electron reduction of O 2 to form H 2 O 2. Meanwhile, the particular morphology provided a large accessible surface area, multi-mass transport channels and short charge transfer distance. The synergy effect of desirable energy band and hierarchical porous nanosheets bring the excellent photocatalytic activity. In addition, the simple preparation procedure and the non-metal properties make it have great potential for the practical application. [ABSTRACT FROM AUTHOR]

In Fe2+/peroxymonosulfate (PMS) activation system, the slow cycle rate of Fe3+/Fe2+ has been considered to be the limiting step in the remediation of organic contaminants. In this paper, commercial molybdenum (Mo) powder is employed as the cocatalyst in Fe2+/PMS system, which can significantly accelerate the Fe3+/Fe2+ cycling efficiency by the exposed bimetallic active sites of Mo4+ and Mo0, and the process is accelerated as the amount of Mo powder increased. The Mo cocatalytic Fe2+/PMS system exhibits an enhanced performance for the activation of PMS and the removal of different aromatic pollutants including dyes, phenolic pollutants and antibiotics, in a wide pH range of 4.0–9.0. Importantly, Mo powder exhibits excellent cycle performance in the PMS activation system, and rhodamine B (RhB) can be removed within 10 min even after 5 cycles. Electron paramagnetic resonance (EPR) prove that the sulfate radicals (SO 4 −) is the major reactive oxides species in the PMS activation, the increase of Fe2+ content induced by the cocatalytic effect of Mo powder can effectively promote the production of SO 4 − and increase the utilization of PMS. In addition, to observe the process of pollutant removal more intuitively, HPLC-MS is used to analyze the decomposing pathway of RhB and sulfadiazine in Mo+FeSO 4 +PMS system. It is believed that this research provides a new idea for the efficient activation of PMS by iron ions in a wide initial pH range, which is expected to be applied to the treatment of large-scale industrial wastewater. Image 1 • The exposed reduction site on Mo powder surface accelerate the Fe2+/Fe3+ cycle in Fe2+/PMS system. • RhB was effectively degraded even at weak alkaline condition in the system. • The system could achieve a significant synergy in the degradation of various aromatic pollutants. • The main degradation pathway of RhB and SD were proposed by HPLC-MS. [ABSTRACT FROM AUTHOR]

We developed an outstanding bimetallic phosphides NiFeP as an alternative of noble metals to realize the improved HER activity of graphitic carbon nitride (g-C 3 N 4) and the prepared NiFeP/g-C 3 N 4 exhibits a high hydrogen production of 3.549 mmol g−1 h−1. The introduction of NiFeP can not only reduce the ΔG H* , but also make the photogenerated electrons transfer directionally, which play a synergistic role in enhancing the activity of HER. • Nickel-iron bimetallic phosphide (NiFeP) is designed onto graphitic carbon nitride. • NiFeP/g-C 3 N 4 exhibited a high HER activity and an improved apparent quantum yield. • Modulated electronic structure and reduced energy barriers can largely facilitate the HER performance. • The direct electron migration pathway accelerate the charge separation. • It provides theoretical guidance for the design and preparation of multi-metallic center photocatalytic system. Bimetallic phosphides have attracted considerable attention in photocatalytic hydrogen evolution reaction (HER), owing to its thermodynamic feasibility. Most reports attributed the HER activity to the reduction of free energy of protonation (ΔG H*), however, few revealed the whereabouts of the photo-induced electrons, which makes the mechanism of HER not very clear. Herein, nickel-iron bimetallic phosphide (NiFeP) is designed onto graphitic carbon nitride (NiFeP/g-C 3 N 4) for the photocatalytic HER, which exhibits a high hydrogen production of 3.549 mmol g−1 h−1. It is found that the co-catalyst of NiFeP can not only reduce the ΔG H* , but also make the photogenerated electrons transfer directionally, which play a synergistic role in enhancing the activity of HER. The reduction of ΔG H2O and ΔG H* over NiFeP in HER can be well demonstrated by the density functional theory (DFT) calculations. Furthermore, the localized distribution of electrons on the surface of NiFeP is verified by measuring the lifetime of photo-generated carriers combined with the REDOX experiment. The shortened lifetime τ, decreased τ1 and τ2 of NiFeP/g-C 3 N 4 indicate that the photoexcited electrons of g-C 3 N 4 are directly transferred to the co-catalyst surface, contributing to the worse delocalization capacity of electrons on the ca-catalyst and its easier reactions with protons trapped on the co-catalyst surface. Furthermore, the degradation with peroxymonosulfate (PMS) confirms the photogenerated holes over 5NiFeP/g-C 3 N 4 are mainly concentrated on the surface of g-C 3 N 4 to decompose H 2 O for the generation of OH, while the photogenerated electrons are directed to the NiFeP to react with the neighboring PMS or protons to form SO 4 − or H 2. Besides, the density of state intensity (DOS) also confirms the photogenerated electron migration pathway at the metal-semiconductor (NiFeP-g-C 3 N 4) interface. Our research clarifies the mechanism of bimetallic phosphides co-catalytic HER system, which will provide theoretical guidance for the design and preparation of multi-metallic center photocatalytic system with a higher HER activity in the future. [ABSTRACT FROM AUTHOR]

Catalytic peroxymonosulfate (PMS) activation processes don't solely rely on electron transfer from dominant metal centers due to the complicated composition and interface environment of catalysts. Herein the synthesis of a cobalt based metal-organic framework containing polyvanadate [V 4 O 12 ] 4- cluster, Co 2 (V 4 O 12 )(bpy) 2 (bpy = 4,4'-bipyridine), is presented. The catalyst demonstrates superior degradation activity toward various micropollutants, with higher highest occupied molecular orbital (HOMO), via nonradical attack. The X-ray absorption spectroscopy and density functional theory (DFT) calculations demonstrate that Co sites act as both PMS trapper and electron donor. In situ spectral characterizations and DFT calculations reveal that the terminal oxygen atoms in the [V 4 O 12 ] 4- electron sponge could interact with the terminal hydrogen atoms in PMS to form hydrogen bonds, promoting the generation of SO 5 * intermediate via both dynamic pull and direct electron transfer process. Further, Co 2 (V 4 O 12 )(bpy) 2 exhibits long-term water purification ability, up to 40 h, towards actual wastewater discharged from an ofloxacin production factory. This work not only presents an efficient catalyst with an electron sponge for water environmental remediation via nonradical pathway, but also provides fundamental insights into the Fenton-like reaction mechanism., (© 2024. The Author(s).)

It is imperative to devise effective removal strategies for high ionization potential (IP) organic pollutants in wastewater as their reduced electron-donating capacity challenges the efficiency of advanced oxidation systems in degradation. Against this backdrop, leveraging the metal-based carbon material structure meticulously, we employed metal-pyridine-N (M-N-C, M=Fe, Co, and Ni) as the electron transfer bridge. This distinctive design facilitated the ordered transfer of electrons from the adsorbent surface to the surface of high IP value pollutants, acting as a "supplement" to compensate for their deficient electron-donating capability, thereby culminating in the selective adsorption of these pollutants. Furthermore, this adsorbent also demonstrated effective removal of trace emerging contaminants (2 mg/L), displayed robust resistance to various salts, exhibited reusability, and maintained stability. These findings carry substantial implications for future carbon-based material design, offering a pathway toward exceptional adsorption performance in treating water pollution., Competing Interests: Competing interests statement:The authors declare no competing interest.

Singlet oxygen ( 1 O 2 ) is an essential reactive species responsible for selective oxidation of organic matter, especially in Fenton-like processes. However, due to the great limitations in synthesizing catalysts with well-defined active sites, the controllable production and practical application of 1 O 2 remain challenging. Herein, guided by theoretical simulations, a series of boron nitride-based single-atom catalysts (BvBN/M, M=Co, Fe, Cu, Ni and Mn) were synthesized to regulate 1 O 2 generation by activating peroxymonosulfate (PMS). All the fabricated BvBN/M catalysts with explicit M-N 3 sites promoted the self-decomposition of the two PMS molecules to generate 1 O 2 with high selectivity, where BvBN/Co possessed moderate adsorption energy and d-band center exhibited superior catalytic activity. As an outcome, the BvBN/Co-PMS system coupled with membrane filtration technology could continuously transform aromatic alcohols to aldehydes with nearly 100 % selectivity and conversion rate under mild conditions, suggesting the potential of this novel catalytic system for green organic synthesis., (© 2024 Wiley-VCH GmbH.)

Effectively managing sewage sludge from Fenton reactions in an eco-friendly way is vital for Fenton technology's viability in pollution treatment. This study focuses on sewage sludge across various treatment stages, including generation, concentration, dehydration, and landfill, and employs chemical composite MoS 2 to facilitate green resource utilization of all types of sludge. MoS 2 , with exposed Mo 4+ and low-coordination sulfur, enhances iron cycling and creates an acidic microenvironment on the sludge surface. The MoS 2 -modified iron sludge exhibits outstanding (>95%) phenol and pollutant degradation in hydrogen peroxide and peroxymonosulfate-based Fenton systems, unlike unmodified sludge. This modified sludge maintains excellent Fenton activity in various water conditions and with multiple anions, allowing extended phenol degradation for over 14 d. Notably, the generated chemical oxygen demand (COD) in sludge modification process can be efficiently eliminated through the Fenton reaction, ensuring effluent COD compliance and enabling eco-friendly sewage sludge resource utilization., Competing Interests: Competing interests statement:The authors declare no competing interest.

Creating efficient catalysts for simultaneous H 2 O 2 generation and pollutant degradation is vital. Piezocatalytic H 2 O 2 synthesis offers a promising alternative to traditional methods but faces challenges like sacrificial reagents, harsh conditions, and low activity. In this study, we introduce a cobalt-loaded ZnO (CZO) piezocatalyst that efficiently generates H 2 O 2 from H 2 O and O 2 under ultrasonic (US) treatment in ambient aqueous conditions. The catalyst demonstrates exceptional performance with ~50.9% TOC removal of phenol and in situ generation of 1.3 mM H 2 O 2 , significantly outperforming pure ZnO. Notably, the CZO piezocatalyst maintains its H 2 O 2 generation capability even after multiple cycles, showing continuous improvement (from 1.3 mM to 1.8 mM). This is attributed to the piezoelectric electrons promoting the generation of dynamic defects under US conditions, which in turn promotes the adsorption and activation of oxygen, thereby facilitating efficient H 2 O 2 production, as confirmed by EPR spectrometry, XPS analysis, and DFT calculations. Moreover, the CZO piezocatalysts maintain outstanding performance in pollutant degradation and H 2 O 2 production even after long periods of inactivity, and the deactivated catalyst due to metal ion dissolution could be rejuvenated by pH adjustment, offering a sustainable solution for wastewater purification., Competing Interests: Competing interests statement:The authors declare no competing interest.

Copper (Cu) is evidenced to be effective for constructing advanced catalysts. In particular, Cu 2 O is identified to be active for general catalytic reactions. However, conflicting results regarding the true structure-activity correlations between Cu 2 O-based active sites and efficiencies are usually reported. The structure of Cu 2 O undergoes dynamic evolution rather than remaining stable under working conditions, in which the actual reaction cannot proceed over the prefabricated Cu 2 O sites. Therefore, the dynamic construction of Cu 2 O active sites can be developed to promote catalytic efficiency and reveal the true structure-activity correlations. Herein, by introducing the redox pairs of Cu 2+ and reducing sugar into a photocatalysis system, it is clarified that the Cu 2 O sub-nanoclusters (NCs), working as novel active sites, are on-site constructed on the substrate via a photoinduced pseudo-Fehling's route. The realistic interfacial charge separation and transformation capacities are remarkably promoted by the dynamic Cu 2 O NCs under the actual catalysis condition, which achieves a milestone efficiency for nitrate-to-ammonia photosynthesis, including the targets of production rate (1.98±0.04 mol g Cu -1  h -1 ), conversion ratio (94.2±0.91 %), and selectivity (98.6 %±0.55 %). The current work develops an effective strategy for integrating the active site construction into realistic reactions, providing new opportunities for Cu-based chemistry and catalysis sciences research., (© 2023 Wiley-VCH GmbH.)

The development of heterogenous catalysts based on the synthesis of 2D carbon-supported metal nanocatalysts with high metal loading and dispersion is important. However, such practices remain challenging to develop. Here, we report a self-polymerization confinement strategy to fabricate a series of ultrafine metal embedded N-doped carbon nanosheets (M@N-C) with loadings of up to 30 wt%. Systematic investigation confirms that abundant catechol groups for anchoring metal ions and entangled polymer networks with the stable coordinate environment are essential for realizing high-loading M@N-C catalysts. As a demonstration, Fe@N-C exhibits the dual high-efficiency performance in Fenton reaction with both impressive catalytic activity (0.818 min -1 ) and H 2 O 2 utilization efficiency (84.1%) using sulfamethoxazole as the probe, which has not yet been achieved simultaneously. Theoretical calculations reveal that the abundant Fe nanocrystals increase the electron density of the N-doped carbon frameworks, thereby facilitating the continuous generation of long-lasting surface-bound • OH through lowering the energy barrier for H 2 O 2 activation. This facile and universal strategy paves the way for the fabrication of diverse high-loading heterogeneous catalysts for broad applications., (© 2023. The Author(s).)

Single-atom catalysts (SACs) are a promising area in environmental catalysis. We report on a bimetallic Co-Mo SAC that shows excellent performance in activating peroxymonosulfate (PMS) for sustainable degradation of organic pollutants with high ionization potential (IP > 8.5 eV). Density Functional Theory (DFT) calculations and experimental tests demonstrate that the Mo sites in Mo - Co SACs play a critical role in conducting electrons from organic pollutants to Co sites, leading to a 19.4-fold increase in the degradation rate of phenol compared to the CoCl 2 - PMS group. The bimetallic SACs exhibit excellent catalytic performance even under extreme conditions and show long-term activation in 10-d experiments, efficiently degrading 600 mg/L of phenol. Moreover, the catalyst has negligible toxicity toward MDA-MB-231, Hela, and MCF-7 cells, making it an environmentally friendly option for sustainable water treatment. Our findings have important implications for the design of efficient SACs for environmental remediation and other applications in biology and medicine.

Catalytic hydrogen peroxide (H 2 O 2 ) generation from oxygen and water enables a sustainable environment to operate in an effective and green energy-to-chemical conversion way, which has attracted increasing interest in the fields of energy production and environment treatment. In light of this, tremendous progresses and developments have been made during the past decades in catalytic H 2 O 2 production for pollutant removal from three perspectives including photocatalysis, electrocatalysis or chemical activation. Herein, we critically review the state-of-the-art developments over various procedures of H 2 O 2 generation and its further application, with the existence of photocatalysts, electrocatalysts, and catalysts, respectively. Benefiting from extensively experimental and theoretical investigations, the performance and stability of H 2 O 2 generation and its utilization can be maneuvered by devising catalytic platform based on numerous catalysts with predominant electronic, chemical and physical properties, which endow the catalysts with efficient electrons transportation, abundant active sites, and sufficient oxygen adsorption for H 2 O 2 generation. Furthermore, this review also discusses the formation mechanism of H 2 O 2 by 2e-ORR and 2e-WOR, as well as its functional process of activating and removing pollutants, and summarizes the design principles of various catalysts by focusing on the formation of H 2 O 2 . We finally highlight the specific challenges and prospects related to the utilization of catalysts and envision the possible future development trends in the fields of pollutant removal., (© 2023 Wiley-VCH GmbH.)

Efficient H 2 harvesting from wastewater instead of pure water can minimize fresh water consumption, which is expected to solve the problem of water shortage in H 2 production process and contribute to carbon neutrality in the environmental remediation, but the inevitable electron depletion caused by electron-consuming pollutants will result in an exhausted H 2 evolution reaction (HER) performance. In this paper, by coupling piezocatalysis and advanced oxidation processes (AOPs) by a MoS 2 /Fe 0 /peroxymonosulfate (PMS) ternary system, extensive types of wastewater achieved considerable H 2 generation, which exceeded the yield in pure water with synchronous advanced degradation of organic pollutants. In addition, profiting from the crucial bridging role of PMS, the H 2 yield in nitrobenzene wastewater after the introduction of PMS-based AOPs increased 3.37-fold from 267.7 μmol·g -1 ·h -1 to 901.0 μmol·g -1 ·h -1 because the presence of PMS both thermodynamically benefited MoS 2 piezocatalytic H 2 evolution and eliminated the electron depletion caused by organic pollutants. By this way, the original repressed H 2 evolution performance in substrate of wastewater not only was regained but even showed a significant enhancement than that in pure water (505.7 μmol·g -1 ·h -1 ). Additionally, the cyclonic piezoelectric reactor was preliminarily designed for future industrialization. This strategy provided a valuable path for the recycling of actual wastewater by fuel production and synchronous advanced treatment.

The universal limit on the pH conditions is disturbing peroxymonosulfate (PMS)-triggered high-valent iron-oxo systems in environmental applications. Here, we propose for the first time the construction of a neutral microenvironment on the surface of Zn-Fe layered double hydroxide (ZnFe-LDH) by using the amphoteric properties of zinc hydroxide, which continuously generates ≡Fe IV =O over a wide pH range of 3.0-11.0 in activating PMS. The ≡Zn(OH) 2 moiety offers a neutral microenvironment at the phase interface, which mitigates the self-decomposition of ≡Fe IV =O by protons and the hydrolysis reaction of iron by hydroxyl groups, which is supported by the Mossbauer spectra, density functional theory calculations and designed experiments. Consequently, ZnFe-LDH/PMS can satisfy the stability in long-term experiments, selectivity under conditions with high salinity or natural organic matter and efficient treatment of actual wastewater., (© 2022 Wiley-VCH GmbH.)