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Graphene oxide (GO) has become one of the emerging and important sole photocatalyst nanomaterials in recent years due to its exceptional/tunable optoelectronic properties, multifunctionality, and eco‐friendly nature. However, challenges remain in tuning surface chemistry, tailoring the band gap, developing doping strategies, and understanding the sole photocatalytic mechanism. This contribution investigated the synthesis of GO via the improved Hummers method by varying the ratio of the oxidizing agents (K2Cr2O7:KMnO4), as well as modifications by nitrogen (N) and boron (B) doping in view of its applications in photocatalytic degradation of organic dye pollutants. Furthermore, changes in surface chemistry, optical, compositional, morphological, and structural properties are investigated to understand the photocatalytic mechanism. The synthesized GO showed a broad spectrum of light absorption with a tunable band gap of 2.4–4.3 eV and exhibited more than 91% degradation of methylene blue dye under direct sunlight. However, the photocatalytic activity decreased after N and B doping attributed to reduced oxygen‐containing functional groups, low surface area, and dopants‐induced bonding configurations within the GO structure. This study provides a new insight into replacing metallic semiconductor photocatalysts with highly affordable, environmentally friendly, and potent metal‐free GO photocatalysts. [ABSTRACT FROM AUTHOR]

The binary heterostructured semiconducting visible light photocatalyst of the iron-doped graphitic carbon nitride/bismuth molybdate (Fe-g-C3N4/Bi2MoO6) composite was prepared by coupling with Fe-doped g-C3N4 and Bi2MoO6 particles. In the present study, a comparison of structural characteristics, optical properties, and photocatalytic degradation efficiency and activity between Fe-doped g-C3N4 particles, Bi2MoO6 particles, and Fe-g-C3N4/Bi2MoO6 composite was investigated. The results of X-ray diffraction (XRD) examination indicate that the hydrothermal Bi2MoO6 particles have a single orthorhombic phase and Fourier transform infrared (FTIR) spectroscopy analysis confirms the formation of Fe-doped g-C3N4. The optical bandgaps of the Fe-doped g-C3N4 and Bi2MoO6 particles are 2.74 and 2.73 eV, respectively, as estimated from the Taut plots obtained from UV-Vis diffuse reflectance spectroscopy (DRS) spectra. This characteristic indicates that the two semiconductor materials are suitable for absorbing visible light. The transmission electron microscopy (TEM) micrograph reveals the formation of the heterojunction Fe-g-C3N4/Bi2MoO6 composite. The results of photocatalytic degradation revealed that the developed Fe-g-C3N4/Bi2MoO6 composite photocatalyst exhibited significantly better photodegradation performance than the other two single semiconductor photocatalysts. This property can be attributed to the heterostructured nanostructure, which could effectively prevent the recombination of photogenerated carriers (electron–hole pairs) and enhance photocatalytic activity. Furthermore, cycling test showed that the Fe-g-C3N4/Bi2MoO6 heterostructured photocatalyst exhibited good reproducibility and stability for organic dye photodegradation. [ABSTRACT FROM AUTHOR]

While Ce3+-doped ZnO nanoparticles have been extensively explored for UV light photocatalytic applications, harnessing their efficacy for visible light photocatalysis remains a significant challenge. This study demonstrates the outstanding degradation efficiency under visible light of Ce3+-doped ZnO nanoparticles synthesized via the sol-gel route. At lower concentrations (<3 mol%), Ce3+ ions seamlessly substitute Zn2+ ions within the ZnO lattice, while at higher dopant levels (≥3 mol%), the formation of CeO 2 nanoparticles on the ZnO surface becomes an additional noteworthy feature. This unique combination in highly Ce3+-doped ZnO nanoparticles leads to the creation of Ce-impurity states (e.g., Ce3+/Ce4+) within the ZnO structure, effectively separating electrons and holes. Consequently, the generation of superoxide radical anions is enhanced, boosting the remarkablely DB71 dye degradation efficiency (>90%) of all highly Ce3+-doped ZnO samples (≥3 mol%) in comparison with pristine and lightly Ce3+-doped ZnO samples (<3 mol%). In all highly Ce3+-doped ZnO samples, 5-mol% doped sample shows the highest DB71 degradation efficiency of 98.4%. This remarkable achievement is observed when utilizing 0.1 g of 5-mol% doped sample, 50 mg/L of initial DB71 concentration, pH of 5, and notablely under visible light irradiation. Furthermore, the DB71 degrading efficiency of ZnO:5%Ce3+ maintains an impressive 90.3% over five cycles from its initial value of 98.4%, underscoring the potential of ZnO:Ce3+ as a promising photocatalyst for practical wastewater treatment. [ABSTRACT FROM AUTHOR]

The discovery of visible active photocatalysts for H2 evolution via water splitting is the most awaited and critical goal of many researchers in recent years. Novel polymeric graphitic carbon nitride (GCN/g-CN) has emerged as a versatile material which has attracted the scientific community and industrialist because of its distinctiveness and outstanding electronic properties. g-CN is a metal free semiconductor as well as non-toxic, biodegradable polymeric material with low band gap energy which makes it a promising candidate as a photocatalyst and its efficiency as a catalyst can be modified by forming a hybrid nanocomposite with other semiconducting materials. Reduced graphene oxide, another metal free 2D material is a very good choice for this purpose. This review is an outlook for the synthesis processes and various properties of both g-CN and graphene. Further, it gives the approaches attempted towards the modifications required and done towards the development of a metal-free nano-hybrid material which is cost-effective, eco-friendly, and highly active visible light catalyst for the watersplitting process. [ABSTRACT FROM AUTHOR]

The binary heterostructured semiconducting visible light photocatalyst of the iron-doped graphitic carbon nitride/bismuth molybdate (Fe-g-C3N4/Bi2MoO6) composite was prepared by coupling with Fe-doped g-C3N4 and Bi2MoO6 particles. In the present study, a comparison of structural characteristics, optical properties, and photocatalytic degradation efficiency and activity between Fe-doped g-C3N4 particles, Bi2MoO6 particles, and Fe-g-C3N4/Bi2MoO6 composite was investigated. The results of X-ray diffraction (XRD) examination indicate that the hydrothermal Bi2MoO6 particles have a single orthorhombic phase and Fourier transform infrared (FTIR) spectroscopy analysis confirms the formation of Fe-doped g-C3N4. The optical bandgaps of the Fe-doped g-C3N4 and Bi2MoO6 particles are 2.74 and 2.73 eV, respectively, as estimated from the Taut plots obtained from UV-Vis diffuse reflectance spectroscopy (DRS) spectra. This characteristic indicates that the two semiconductor materials are suitable for absorbing visible light. The transmission electron microscopy (TEM) micrograph reveals the formation of the heterojunction Fe-g-C3N4/Bi2MoO6 composite. The results of photocatalytic degradation revealed that the developed Fe-g-C3N4/Bi2MoO6 composite photocatalyst exhibited significantly better photodegradation performance than the other two single semiconductor photocatalysts. This property can be attributed to the heterostructured nanostructure, which could effectively prevent the recombination of photogenerated carriers (electron–hole pairs) and enhance photocatalytic activity. Furthermore, cycling test showed that the Fe-g-C3N4/Bi2MoO6 heterostructured photocatalyst exhibited good reproducibility and stability for organic dye photodegradation.

Palladium@mesoporous titania core@shell nanoparticles with uniform and narrow particle size distribution were synthesised using a four component "water in oil" microemulsion system. The prepared materials were well characterised using N2 adsorption–desorption measurements, temperature program oxidation, X-ray diffraction, ICP-OES, DRS UV-Vis, PL, TGA and transmission electron microscopy techniques. The core@shell nanoparticles showed very good absorption in both the UV and visible regions and a low bandgap, indicating that the prepared materials are visible-light-active, unlike the pristine TiO2 P25. The activity of the prepared materials was evaluated in the photodegradation of phenol using both UV and visible light, in batch and continuous flow trickle-bed and Taylor flow photoreactors. The prepared 2%Pd@mTiO2 core@shell nanoparticles showed better photocatalytic performance for phenol degradation in visible light in comparison to pristine TiO2 P25 and conventional 0.5%Pd/TiO2 P25 catalysts. The TiO2 P25 and conventional 0.5%Pd/TiO2 P25 catalysts showed gradual catalyst deactivation due to photocorrosion, the deposition of intermediates and Pd metal leaching. In comparison, the 2%Pd@mTiO2 catalyst showed higher catalyst stability and reusability. The 2%Pd@mTiO2 catalysts showed very high and stable phenol degradation (97% conversion) in continuous flow over 52 h. The results showed the feasibility of utilising the developed continuous Taylor flow photoreactor for phenol degradation or as a wastewater treatment plant. [ABSTRACT FROM AUTHOR]

Nanostructured composite photocatalysts, consist of multi-walled carbon nanotubes (MWCNT), and cubic face magnesium oxide (MgO) were prepared by sol–gel methodology. Powder X-ray powder diffraction (PXRD) results reveals that the sample was composed of CNT and cubic MgO. Field emission scanning electron microscope (FESEM) studies showed that multi-walled CNTs with the outer diameters of 20–25 nm and length up to several micrometers, which were uniformly coated with the disc like nanoparticles whose diameter was in the range of 20–30 nm. The optical absorption edge was shifted to longer wavelength for MgO/MWCNTs composite, which is confirmed through UV-vis diffuse reflectance (DRS) analysis. The prepared MgO-MWCNTs composite proficiently catalyzed the photodegradation of phenol and congo-red under visible light irradiation. After seven trials, just 3.5 % of the photocatalytic efficiency of the MgO/MWCNTs composite was lost to congo-red, which is an excellent result. We go into great detail about the potential photocatalytic pathway as well. When used in a photovoltaic device, the MgO/MWCNT CE showed high PCE of 5.15% with long term stability. The EIS results also prove that lower resistance and high electron life time. The DSSC based on MC3 CE enhanced the photocurrent conversion efficiency to 5.12% compared to 3.71% with MgO CE. The DSSC based on MC3 composite CE exhibited highest IPCE performance (79%), whereas the MgO, MC1 and MC2 based CEs showed lower IPCE value of nearly 48%, 52% and 42%, respectively [ABSTRACT FROM AUTHOR]

Rampant discharge of industrial wastes containing non-biodegradable colored dyes to water bodies has prompted the development of an environment-friendly photocatalytic process using nontoxic, photostable water soluble photocatalyst. In this work, bare undoped carbon dots (CDots) based photocatalyst has been reported. The carbon dots were synthesized via the pyrolysis method using a single source, ammonium citrate; the reported carbon dots were characterized using HR-TEM, XRD, FTIR, XPS, Photoluminescence (P.L.), TGA, and UV–Vis spectroscopy. The catalytic behavior of the synthesized carbon dots was tested against two water-soluble industrial dyes (Methylene Blue (M.B.) and Congo Red (C.R.)). The synthesized carbon dots exhibited excellent photocatalytic activity under visible light irradiation facilitating 96% degradation of MB within 55 min and 98% degradation of C.R. within 60 min. A plausible mechanism for the photocatalytic degradation of studied dyes was proposed based on comprehensive active species trapping experiments. The photogenerated holes (h+) and superoxide radicals (O2 .−) were the main active species responsible for the degradation of studied dyes. The kinetic studies revealed that the cationic methylene blue dye degradation by BUCDs followed the modified Freundlich kinetic model with rate constant 0.063 and anionic congo red dye depicted closed correlation with both parabolic diffusion model and modified Freundlich kinetic model with rate constants 0.256 and 0.196. The synthesized BUCDs showed no cytotoxicity in HCT human colon cancer cell lines, thus establishing their nontoxic nature.

High stability and efficient charge separation are two critical factors to construct high-performance photocatalysts. Here, an efficient strategy was provided to fabricate the nanocomposite of graphitic carbon nitride/ferroferric oxide/reduced graphene oxide (g-C3N4/Fe3O4/RGO). The degradation of rhodamine B (RhB) by g-C3N4/Fe3O4/RGO nanocomposite followed the pseudo-first-order kinetics. The g-C3N4/Fe3O4/RGO nanocomposite exhibited excellent stability and magnetically separable performance. It was ascertained that the quantum efficiency and separation efficiency of photoexcited charge carriers of g-C3N4/Fe3O4/RGO nanocomposite were obviously improved. Particularly, the g-C3N4/Fe3O4/RGO nanocomposite with 3 wt.% RGO presented 100% degradation efficiency under visible light irradiation for 75 min. The remarkable photocatalytic degradation activity is attributed to the synergistic interactions among g-C3N4, Fe3O4, and RGO, along with the efficient interfacial charge separation. [ABSTRACT FROM AUTHOR]

Ammonia is a promising material as a direct source of green hydrogen production. This paper reports a method for mass production of hydrogen from liquid NH 3 (NH 4 OH) through a photocatalytic decomposition reaction using liquid plasma. In this reaction, the highest hydrogen production rate was observed in the TiO 2 photocatalyst doped with N and metal ions as a photocatalyst sensitive to visible light with a low bandgap. At this time, the hydrogen production rate was obtained as about 142 L/g∙h. This is due to the high photoactivity of the visible light-sensitive photocatalyst in liquid plasma emitting strong visible light and ultraviolet light. The H 2 production rate obtained from the decomposition of liquid NH 3 by plasma discharge to the catalyst was higher than the H 2 production rate obtained from the NH 3 electrolysis process. [Display omitted] • Hydrogen production by liquid phase plasma was assessed in ammonium hydroxide solution. • The effects of irradiation of the liquid phase plasma were evaluated in the decomposition. • Modified TiO 2 was prepared by doping metal ions and nitrogen according to sol-gel method. • The highest rate of H 2 evolution obtained on the N- and Ni-codoped TiO 2 was about 142 L/g∙h. • The liquid-plasma emitting strong light led the high rate of H 2 production into the reactant. [ABSTRACT FROM AUTHOR]

Based on the structure related to the high-temperature superconductor yttrium-barium-copper oxide, two novel high-efficiency visible light photocatalysts were created in this study. The yttrium-barium oxide (YBO) semiconductors Y 2 Ba 3 O 6 (YB3O) and Y 2 Ba 4 O 7 (YB4O) were prepared by a copper-free solid-phase sintering method. They were applied for the effective treatment of dye-containing wastewater by photocatalysis under visible light irradiation. The degradation efficiency of methylene blue (MB) reached more than 95% within 10 min. Stable visible light degradation of methyl orange (MO) was achieved in the presence of YB3O and YB4O. The electron spin resonance technique and active substance capture technique confirmed the presence of superoxide radicals (·O 2 −), hydroxyl radicals (·OH) and holes (h VB +) under visible light illumination. UV–Vis diffuse reflectance spectroscopy analysis showed that the direct optical band gaps of YB3O and YB4O were 2.550 eV and 2.583 eV, respectively, which resulted in their high visible absorption at 486.27 nm and 480.06 nm. After five cycles, the recoveries of YB3O and YB4O reached 67.15% and 72.98%. Therefore, YB3O and YB4O are considered as powerful semiconductor catalysts for the photocatalytic degradation of organic dyes in wastewater. • Synthesis of yttrium -barium oxide (YBO) visible light catalyst. • Y 2 Ba 3 O 6 (YB3O) and Y 2 Ba 4 O 7 (YB4O) show a forbidden band width of 2.550 eV and 2.583 eV respectively. • The effective degradation of methylene blue was achieved within 10 min under visible light. • The mineralization of the total organic carbon in the degraded solutions of both dyes reached close to 80%. [ABSTRACT FROM AUTHOR]

Palladium@mesoporous titania core@shell nanoparticles with uniform and narrow particle size distribution were synthesised using a four component ‘‘water in oil’’ microemulsion system. The prepared materials were well characterised using N2 adsorption–desorption measurements, temperature program oxidation, X-ray diffraction, ICP-OES, DRS UV-Vis, PL, TGA and transmission electron microscopy techniques. The core@shell nanoparticles showed very good absorption in both the UV and visible regions and a low bandgap, indicating that the prepared materials are visible-light-active, unlike the pristine TiO2 P25. The activity of the prepared materials was evaluated in the photodegradation of phenol using both UV and visible light, in batch and continuous flow trickle-bed and Taylor flow photoreactors. The prepared 2%Pd@mTiO2 core@shell nanoparticles showed better photocatalytic performance for phenol degradation in visible light in comparison to pristine TiO2 P25 and conventional 0.5%Pd/TiO2 P25 catalysts. The TiO2 P25 and conventional 0.5%Pd/TiO2 P25 catalysts showed gradual catalyst deactivation due to photocorrosion, the deposition of intermediates and Pd metal leaching. In comparison, the 2%Pd@mTiO2 catalyst showed higher catalyst stability and reusability. The 2%Pd@mTiO2 catalysts showed very high and stable phenol degradation (97% conversion) in continuous flow over 52 h. The results showed the feasibility of utilising the developed continuous Taylor flow photoreactor for phenol degradation or as a wastewater treatment plant.

A green method for depositing a CuO layer with good adhesion and a large surface area on a support of activated alumina (Al2O3) was evaluated. The relatively simple method consists of adsorption of a copper salt on the surface of Al2O3, formation of Cu(OH)2, and subsequent decomposition of the hydroxide to CuO. The XRD confirmed that the deposited photocatalyst crystalized at low temperatures (80 °C). Furthermore, BET measurements show a surface area of about 90 m2/g. The large surface area is the result of the speed of the conversion and decomposition reactions. The photokilling properties of the prepared photocatalyst were evaluated using E. coli cells and the leaching of copper ions was determined using ICP-MS. The photocatalytic efficiency was also evaluated by the degradation of an organic azo dye. The prepared photocatalyst shows good activity in the purification and disinfection of treated water. The described method is economical, fast, and can be considered green, since the only byproducts are water and NaCl. [ABSTRACT FROM AUTHOR]

Research on antiviral agents to inactivate SARS-CoV-2 is still a concern of researchers. Many innovations have been made, one of which is coating the surface of cloth masks using photocatalyst materials. Visible light photocatalysts have been shown to have antimicrobial properties in sunlight. The study of material modification becomes important to select and optimize the supporting materials used. We observed that modifications with nano-silica particles (SiO2) have good transmission capabilities and can be produced from natural sources (biological and non-biological). Therefore, this utilization is carried out to apply the principle of zero waste, namely renewable natural sources as a source/precursor of nano-silica. In this study, we focus on renewable research related to the use of natural nano-silica as supporting material for visible light photocatalysts will be explored to be coated on polyester mask fabrics as an effort to inactivate SARS-CoV-2 on the surface of the mask. [ABSTRACT FROM AUTHOR]

MIL-53(Fe) was successfully prepared and deposited on the surface carboxylated polyester (PET) fiber by an optimized conventional solvothermal or industrialized high temperature pressure exhaustion (HTPE) process to develop a PET fiber supported MIL-53(Fe) photocatalyst (MIL-Fe@PET) for the degradation of polyvinyl alcohol (PVA) in water under light emitting diode (LED) visible irradiation. On the basis of several characterizations, MIL-Fe@PET was tested for the photocalytic ability and degradation mechanism. It was found that temperature elevation significantly enhanced the formation and deposition of MIL-53(Fe) with better photocatalytic activity. However, higher temperature than 130°C was not in favor of its photocatalytic activity. Increasing the number of surface carboxyl groups of the modified PET fiber could cause a liner improvement in MIL-53(Fe) loading content and photocatalytic ability. High visible irradiation intensity also dramatically increased photocatalytic ability and PVA degradation efficiency of MIL-Fe@PET. Na 2 S 2 O 8 was used to replace H 2 O 2 as electron acceptor for further promoting PVA degradation in this system. MIL-Fe@PET prepared by HTPE process showed higher MIL-53(Fe) loading content and slightly lower PVA degradation efficiency than that prepared by solvothermal process at the same conditions. These findings provided a practical strategy for the large-scale production of the supported MIL-53(Fe) as a photocatalyst in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

3D CdMoO 4 @CdS core-shell visible-light-driven photocatalyst was successfully synthesized by in-situ method. Various analytical techniques show that CdS dots are uniformly loaded on the surface of CdMoO 4 hollow microspheres constructing a 3D core-shell CdMoO4@CdS heterojunction. The photocatalytic activity of nanocomposites was studied by degrading malachite green (MG) under visible light irradiation. It was found that the composite material can effectively degrade MG under visible light irradiation. Furthermore, the enhanced photocatalytic efficiency for the composite material is due to the effective diffusion and separation of photogenerated carriers. [Display omitted] [ABSTRACT FROM AUTHOR]

Overall water splitting to generate H2 and O2 is vital in solving energy problem. It is still a great challenge to seek efficient visible light photocatalyst to realize overall water splitting. In this work, the tetragonal zircon BiVO4 is prepared by epitaxial growth on FTO substrate and its overall water splitting reaction is studied. Under the influence of epitaxial strain, the conduction band position shifts negatively and beyond H+/H2 reduction potential (0 V vs NHE), which enables it to possess the photocatalytic hydrogen evolution activity. After loading cocatalysts, the overall water splitting (λ > 400 nm) is realized (H2: ≈65.7 µmol g−1 h−1, O2: ≈32.6 µmol g−1 h−1), and the value of solar hydrogen conversion efficiency is 0.012%. The single‐particle photoluminescence (PL) spectra and PL decay kinetics tests demonstrate the cocatalysts are beneficial to the separation and transfer of carriers. The new strategy of adjusting the band structure by strain is provided. [ABSTRACT FROM AUTHOR]

Overall water splitting to generate H2 and O2 is vital in solving energy problem. It is still a great challenge to seek efficient visible light photocatalyst to realize overall water splitting. In this work, the tetragonal zircon BiVO4 is prepared by epitaxial growth on FTO substrate and its overall water splitting reaction is studied. Under the influence of epitaxial strain, the conduction band position shifts negatively and beyond H+/H2 reduction potential (0 V vs NHE), which enables it to possess the photocatalytic hydrogen evolution activity. After loading cocatalysts, the overall water splitting (λ > 400 nm) is realized (H2: ≈65.7 µmol g−1 h−1, O2: ≈32.6 µmol g−1 h−1), and the value of solar hydrogen conversion efficiency is 0.012%. The single‐particle photoluminescence (PL) spectra and PL decay kinetics tests demonstrate the cocatalysts are beneficial to the separation and transfer of carriers. The new strategy of adjusting the band structure by strain is provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin triangle CeO 2 /g-C 3 N 4 heterojunctions. • Type II heterojunctions 10%CeO 2 /CN showed significantly enhanced MP removal. • Synergistic effect of the effective combination of CeO 2 triangles on CN. • Rate constant was 3.8 and 11.3 times higher than that of CN under solar/vis light. • 1H NMR experiments we assume that after 420 min the MP was completely degraded. In this work, an efficient photocatalytic system for methylparaben (MP) removal, using solar (λ > 360 nm) and visible (λ > 420 nm) light-driven CeO 2 /g-C 3 N 4 (CeO 2 /CN) heterojunctions is reported for the first time. The physicochemical properties of pure CeO 2 , CN, and CeO 2 /CN composites were investigated using characterization techniques, such as XRD, FESEM-EDS, TEM, UV–Vis, PL, XPS, and electrochemical spectroscopy. Among the catalysts with different mass ratios of CeO 2 , 10 %CeO 2 /CN showed the best photocatalytic performance. This is attributed to the enhanced charge carrier's separation because of the proper band-edge alignment between CN and CeO 2 components, and the strong visible light absorbance. The photocatalytic degradation of MP followed the first-order kinetics, and the 10 %CeO 2 /CN catalyst exhibited a 3.8- and 11.3-times higher reaction rate (k) constant than that of pure CN, investigated under solar and visible light illumination, respectively. Further, scavenger trapping experiments confirmed that hydroxyl radicals (OH .) and dissolved oxygen are the predominant active species in MP oxidation over 10 %CeO 2 /CN composite catalyst. 1H NMR and LCMS-HPLC results and observations showed complete degradation of MP (0.1 g/L) to CO 2 and H 2 O after 7 h of solar irradiation, due to the absence of the representative peaks of MP and its organic degradation products (e.g. phenols, benzoates). [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of novel multifunctional Fe 3 O 4 /ZnO/L-Lysine Functionalized Graphene Oxide nanocomposite. • Synergetic dark catalytic & visible photocatalytic activities of nanocomposite for efficient organic pollutant degradation. • Proposed double Z-scheme mechanism for enhanced visible photocatalytic activity of nanocomposite. • Dark catalytic activity via ROS generated from ZnO oxygen vacancies & stored electrons inLys-rGO. • The nanocomposite effectively degrades the mixture of organic pollutants including MB, TC, CIP, & RhB. Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe 3 O 4 /ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe 3 O 4 /ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite's dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies. [ABSTRACT FROM AUTHOR]

Abstract Overall water splitting to generate H2 and O2 is vital in solving energy problem. It is still a great challenge to seek efficient visible light photocatalyst to realize overall water splitting. In this work, the tetragonal zircon BiVO4 is prepared by epitaxial growth on FTO substrate and its overall water splitting reaction is studied. Under the influence of epitaxial strain, the conduction band position shifts negatively and beyond H+/H2 reduction potential (0 V vs NHE), which enables it to possess the photocatalytic hydrogen evolution activity. After loading cocatalysts, the overall water splitting (λ > 400 nm) is realized (H2: ≈65.7 µmol g−1 h−1, O2: ≈32.6 µmol g−1 h−1), and the value of solar hydrogen conversion efficiency is 0.012%. The single‐particle photoluminescence (PL) spectra and PL decay kinetics tests demonstrate the cocatalysts are beneficial to the separation and transfer of carriers. The new strategy of adjusting the band structure by strain is provided.

Highly efficient visible light photocatalysts are necessary to address the water pollution caused by antibiotics. In the present study, bismuth oxybromide-rice husk-derived carbon (BiOBr-RHC) composites (with different wt% of RHC) were prepared via a simple solid-state method. Results of the studies indicate that the use of rice husk carbon has a considerable effect on the degradation of the commonly used fluoroquinolone antibiotic norfloxacin (NOR). BiOBr-RHC-10 exhibits the highest catalytic degradation towards NOR under visible light irradiation among the developed composite catalysts. Introducing carbon in the composites provides better separation of charge carriers, thereby reducing the recombination rate of electron-hole pairs. The promising visible-light-driven catalytic activity of the BiOBr-RHC composite makes it a potential candidate for the effective degradation of the antibiotic present in wastewater. [Display omitted] • Synthesis of visible light activate BiOBr-RHC via solid state reaction method. • Among different wt% of RHC, BiOBr-RHC-10 composite exhibit better photocatalytic efficiency. • Approximately 93% of the Norfloxacin antibiotic was degraded within 180min. [ABSTRACT FROM AUTHOR]

Poly(ionic liquid)s nanofiber (PIL NF) membrane was derived from polyacrylonitrile by converting its cyano groups to imidazoline moieties via cyclization with ethylenediamine, followed by quaternization with 1-bromobutane. The novel PIL NF is further decorated with photocatalyst phosphotungstic acid PW12 via anion exchanging to give PW-PIL. The degradation rate of the novel supported photocatalyst towards methyl orange irradiated under visible light was found to be 98%. In addition, the nanofiber membrane morphology is beneficial for easy recycling, and 98% of original degradation rate was maintained after 5 cycles of photocatalysis degradation. This robust, efficient, and recyclable material offers a new approach for serving as catalyst supporter. The photocatalyst PW-PIL is reported for the first time. The inexpensive functional membrane is used to exploit the sun as a cheap and clean source of light. [ABSTRACT FROM AUTHOR]

One of the major causes of excess CO2 in the atmosphere is the direct burning of biomass waste, which can be obviated by the photocatalytic biomass conversion to useful/valuable chemicals/fuels, a sustainable and renewable approach. The present research work is focused on the development of a novel Zn–Fe LDH by a simple co-precipitation method and its utilization for the photocatalytic conversion of a rice husk extract (extracted from rice husk by means of pyrolysis) to value-added products. The synthesized, pure Zn–Fe LDH was characterized by various analytical techniques such as XRD, SEM, FTIR, and UV–Visible DRS spectroscopy. The rice husk extract was converted in a photocatalytic reactor under irradiation with 75 W white light, and the valued-added chemicals were analyzed by gas chromatography–mass spectrometry (GC–MS). It was found that the compounds in the rice husk extract before the photocatalytic reaction were mainly carboxylic acids, phenols, alcohols, alkanes (in a small amount), aldehydes, ketones, and amines. After the photocatalytic reaction, all the carboxylic acids and phenols were completely converted into alkanes by complex reactions. Hence, photocatalytic biomass conversion of a rice husk extract was successfully carried out in the present experimental work, opening new avenues for the development of related research domains, with a great potential for obtaining an alternate fuel and overcoming environmental pollution. [ABSTRACT FROM AUTHOR]

Photocatalysis is the process which used to remove the dye from the effluent. Here, we have used earth-abundant chalcogenide Cu2SnS3 (CTS) thin film as a photocatalyst to remove the dye (methylene blue) under visible light irradiation. A low cost ultrasonic spray pyrolysis was used to deposit the film on soda-lime glass substrate in a single step at optimized temperature 500 °C. The structural, morphological and optical properties of the CTS film have been studied using XRD, SEM and UV–Vis spectroscopy. Structural analysis confirms the formation of Cu2SnS3 tetragonal structure without any secondary impurities. SEM image indicates the surface of this film is smooth and uniform. Bandgap of film is found to be 1.35 eV. Photocatalysis activity of CTS thin film is studied by degrading methylene blue (MB) dye (1 × 10–5 M) in water solution under visible light irradiation. It degrades 90% MB in 3 h. To evaluate the industrial effluent, we have studied the photocatalytic activity in different pH (4, 7, 9) medium. It shows that the MB degradation is faster in the base medium compare to acidic or neutral medium. It takes 1 h to degrade 90% dye in base medium. Films are showing good repeatable performance of the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Pure and Sn-doped goethite (α-FeOOH) nanoparticles with good uniformity were synthesized by a facile precipitation method. The effects of Sn doping on the particle size and shape, structural, thermal, vibrational, optical and photocatalytic properties of prepared goethite nanoparticles were investigated. The Sn4+-for-Fe3+ substitution in the crystal structure of goethite was proved by determination of a significant unit cell expansion (the effect of larger Sn4+ ions) and a substantial reduction of the hyperfine magnetic field (the effect of magnetic dilution by non-magnetic Sn4+ ions). Sn doping induced a decrease in length and an increase in thickness of goethite nanocrystallites and nanoparticles, i.e., the change in particle shape from thin goethite nanorods to shorter and thicker Sn-doped goethite nanoellipsoids and nanocuboids. Thermal dehydroxylation of goethite was shifted to significantly higher temperatures by the Sn4+-for-Fe3+ substitution. The optical band gap of goethite nanoparticles narrowed with the increased Sn4+-for-Fe3+ substitution. The visible light photocatalytic efficiency for rhodamine B (RhB) degradation by a heterogeneous photo-Fenton process was gradually enhanced by Sn doping from 38% for pure goethite nanorods to 55% for Sn-doped nanoellipsoids and 70% for Sn-doped goethite nanocuboids. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen peroxide production from water and oxygen offers a clean and sustainable alternative to the conventional energy-intensive anthraquinone oxidation method. Compared to powdered covalent triazine frameworks (CTFs), the film morphology of CTFs provides better connectivity in 2D, yielding several advantages: more efficient connections between active sites, reduced electron-hole pair recombination, increased resistance to superoxide radical induced corrosion, and decreased light scattering. Leveraging these benefits, it has incorporated dual active sites for both the oxygen reduction reaction (ORR) and the water oxidation reaction (WOR) into a CTF film system. This dual-active CTF film demonstrated an exceptional hydrogen peroxide production rate of 19 460 µmol h⁻¹ m⁻ 2 after 1 h and 17 830 µmol h⁻¹ m⁻ 2 after 5 h under visible light irradiation (≥420 nm) without the need for sacrificial agents., (© 2024 Wiley‐VCH GmbH.)

Titanium dioxide (TiO 2) has been acknowledged as one of the efficient photocatalysts in the UV region. To extend the photo-absorption region toward visible lights, the TiO 2 nanowires enclosed with carbon shells (TiO 2 @carbon core-shell nanowires) were synthesized by a chemical vapor deposition technique at various temperatures from 650 to 950 °C. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that TiO 2 cores and carbon shells are rutile and graphitic structures, respectively. From Raman spectra, the peak intensity of the E g mode was observed to be redshifted with elevated growth temperatures due to the increase in oxygen vacancies in the TiO 2 @carbon core-shell nanowires. From X-ray photoelectron spectroscopy (XPS) results, the oxygen vacancies were strongly related to the Ti3+ ions. The UV–visible spectroscopic studies show a possible decrease in photocatalytic energy from 3.1 to 2.7 eV for the TiO 2 @carbon core-shell nanowires, indicating that the light absorption was enhanced in the visible-light region. The optical absorbance results confirmed the presence of the mid-gap states due to the oxygen vacancies, which are responsible for the visible-light absorption. The photocatalytic activity of the TiO 2 @carbon core-shell nanowires studied by methylene blue (MB) dye degradation is effective under visible lights. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ag-decorated ZnO nanoflowers were synthesized and fully characterized. • This synthetic method was facile and rapid. • Efficient removal of tetracycline was observed under visible light within 30 min. • The degradation pathway of tetracycline was identified by LC/MS and ESI/MSn methods. • The obtained materials also exhibited remarkable stability and repeatability. A high potential nanostructure photocatalyst, Ag-decorated ZnO nanoflowers (Ag/ZnO NFs), was synthesized by a rapid one-pot surfactant-free microwave-assisted aqueous solution method. The morphology, structure, and optical property of Ag/ZnO were well-characterized. The method qualifies to be energy conserving and environment friendly. The size of the flower petals ranges from 200 to 250 nm and highly dispersed Ag nanoparticles (NPs) with dimensions ranging from 10 to 30 nm were anchored onto the surface of them. The as-prepared Ag/ZnO demonstrated enhanced photocatalytic performance in eliminating tetracycline (TC) aqueous solution under the illumination of visible light. The Ag/ZnO exhibited 100% degradation efficiency within 30 min. The effect of operating parameters such as pH, catalyst dose, and TC concentration was investigated. The reaction byproducts were identified by LC/APCI-MS (liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry) and ESI-MSn (electrospray ionization tandem mass spectrometry) analysis and a pathway was proposed as well. Kinetic studies indicated that the photodegradation process follows pseudo-first-order kinetics. The enhanced photocatalytic activity was due to the special architecture, the suppression of electron/hole (e–/h+) pair recombination, and the acceleration of surface charge transfer induced by the highly dispersive Ag NPs, which was further demonstrated by the cyclic voltammetry measurement. [ABSTRACT FROM AUTHOR]

A wide range of processes have been adopted for environmental remediation; among them, photocatalysis appeared as an appealing strategy for degradation of organic pollutants. Heterogeneous photocatalysis efficiently dissociates the charge carriers and helps in reducing the rapid recombination rate of charge carriers resulting in enhanced photocatalytic degradation. A semiconductor photocatalyst graphitic carbon nitride (g-C3N4), when doped with metals or non-metals, showed increased degradation abilities. Hence, a ternary photocatalyst was synthesized by thermal condensation of urea coupled with ferric tungstate (FeWO4) and doped with a noble metal (Ag) resulting in visible light susceptive semiconductor photocatalyst Ag/FeWO4/g-C3N4. The characterization of the fabricated composite was done by Fourier transform infrared, scanning electron microscopy energy-dispersive X-ray, and X-ray diffraction. The Ag/FWO/GCN was used to degrade the rhodamine B (RhB) dye. Under sunlight, Ag/FeWO4/g-C3N4 showed enhanced photocatalytic degradation of rhodamine B dye, which was ascribed to the change in bandgap and reduced charge recombination. The parameters used for the optimization of the photocatalyst were pH, catalyst dose, oxidant dose, and irradiation time. The composite (Ag/FeWO4/g-C3N4) showed ~ 98% degradation of RhB dye under optimized conditions (i.e., pH = 8, catalyst dose = 50 mg/100 ml, oxidant dose = 9 mM, irradiation time = 120 min and RhB conc. 50 ppm). [ABSTRACT FROM AUTHOR]

Lignin-based graphene oxide (L-GO), zinc oxide (ZnO), and modified L-GO–ZnO nanocomposites are prepared to explore the photocatalytic efficiency of the catalysts under UV–visible light irradiation. The absorbance of dye's solution (rhodamine B) at regular intervals has been recorded at λmax = 553 nm using a UV–Vis spectrophotometer. The kinetics parameters, viz. half-life (t1/2), time constant τ (Tau), and rate constant (k), have been evaluated by integrated rate expression to predict the order of the reaction. The rate constant for the reactions has been evaluated to be k_L-GO–ZnO = 1.46 × 10–1, k_ZnO = 2.23 × 10–2, and k_L-GO = 1.740 × 10–2 min−1. The degradation reaction is predicted to follow the first-order kinetics when the data are fitted to the integrated rate expression, kt = -ln(D/D0). The interactions of the dye and the catalyst have been probed by FTIR spectroscopy. The percent degradation efficiency of ZnO, L-GO, and L-GO–ZnO catalyst is 85.96, 83.15, and 91.75, respectively. [ABSTRACT FROM AUTHOR]

One of the major causes of excess CO2 in the atmosphere is the direct burning of biomass waste, which can be obviated by the photocatalytic biomass conversion to useful/valuable chemicals/fuels, a sustainable and renewable approach. The present research work is focused on the development of a novel Zn–Fe LDH by a simple co-precipitation method and its utilization for the photocatalytic conversion of a rice husk extract (extracted from rice husk by means of pyrolysis) to value-added products. The synthesized, pure Zn–Fe LDH was characterized by various analytical techniques such as XRD, SEM, FTIR, and UV–Visible DRS spectroscopy. The rice husk extract was converted in a photocatalytic reactor under irradiation with 75 W white light, and the valued-added chemicals were analyzed by gas chromatography–mass spectrometry (GC–MS). It was found that the compounds in the rice husk extract before the photocatalytic reaction were mainly carboxylic acids, phenols, alcohols, alkanes (in a small amount), aldehydes, ketones, and amines. After the photocatalytic reaction, all the carboxylic acids and phenols were completely converted into alkanes by complex reactions. Hence, photocatalytic biomass conversion of a rice husk extract was successfully carried out in the present experimental work, opening new avenues for the development of related research domains, with a great potential for obtaining an alternate fuel and overcoming environmental pollution.

Poly(ionic liquid)s nanofiber (PIL NF) membrane was derived from polyacrylonitrile by converting its cyano groups to imidazoline moieties via cyclization with ethylenediamine, followed by quaternization with 1-bromobutane. The novel PIL NF is further decorated with photocatalyst phosphotungstic acid PW12 via anion exchanging to give PW-PIL. The degradation rate of the novel supported photocatalyst towards methyl orange irradiated under visible light was found to be 98%. In addition, the nanofiber membrane morphology is beneficial for easy recycling, and 98% of original degradation rate was maintained after 5 cycles of photocatalysis degradation. This robust, efficient, and recyclable material offers a new approach for serving as catalyst supporter. The photocatalyst PW-PIL is reported for the first time. The inexpensive functional membrane is used to exploit the sun as a cheap and clean source of light.

In this study, a high-efficiency photocatalyst was synthesized by Mn2+-doped ZnO nanofibres (NFs) fabricated by facile electrospinning and a following annealing process, in which Mn2+ successes incorporate to ZnO NFs lattice without changing any morphology and crystalline structure of ZnO. The photodegradation properties of ZnO loading with different concentrations of Mn2+ (5, 10, 15 and 50 at%) were investigated. The 50% MnO–ZnO composite owns excellent active photocatalytic performance (quantum efficiency up to 7.57%) compared to pure ZnO (0.16%) under visible light and can be considered as an efficient visible light photocatalyst material. We systematically analysed its catalytic mechanism and found that the enhancement belongs to the Mn doping effect and the phase junction between MnO and ZnO. The dominant mechanism of Mn doping leads to the presence of impurity levels in the band gap of ZnO, narrowing the optical band gap of ZnO. In addition, doped Mn2+ ions can be used as electron traps that inhibit the recombination process and promote electron–hole pair separation. In summary, this paper provides a convenient method for fabricating highly efficient visible light photocatalysts using controlled annealing.

Doping with noble metal ions or doping with nitrogen has been attempted to prepare TiO2 that reacts even in visible light. In this study, TiO2 was doped with nitrogen and various metal ions instead of noble metals. The TiO2 photocatalysts doped with metal ions (Fe, Ag, Ni) and nitrogen were prepared by a sol-gel method. Their physicochemical properties were characterized and their photocatalytic activities were investigated under visible light irradiation. In TiO2 doped with metal ions and nitrogen, the light absorption region was extended to visible light. The photoluminescence intensity was much greater in N/Ni/TiO2 than in N/Ag/TiO2 and N/Fe/TiO2. The photolysis activities of N/Ni/TiO2 were the highest in formaldehyde decomposition and methylene blue decomposition. The sterilization efficiency of N/Ni/TiO2 was the highest in the evaluation test for the inhibition of the proliferation of Pseudomonas aeruginosa. The bandgap of N/Ni/TiO2 was 2.4 eV, which was significantly lower than that of anatase TiO2 (3.2 eV). The N/Ni/TiO2 had a much higher optical intensity than other metal ion-doped TiO2, so it was highly active under visible light irradiation.

BACKGROUND Nitrogen‐doped titanium dioxide (TiO2) photocatalyst was synthesized successfully by a low temperature microwave‐assisted sol–gel method. Ethylenediamine was used as a source of nitrogen dopants to extend and improve the photoresponse of the materials to visible light. The photocatalysts were characterized by several techniques to determine the structural, textural and optical characteristics. The activity of the materials was tested in the photoreduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) under visible light. RESULTS: The results indicate that nitrogen ions were substitutedly doped into oxygen sites of the TiO2 lattice, resulting in band gap narrowing, which significantly promotes the visible light absorption of TiEN catalysts. When initial ethylenediamine concentration was increased, the content of nitrogen dopant and optical absorption in the visible region increased. Moreover, it was found that TiEN photocatalyst significantly enhances the photoreduction of 4‐NP in comparison to the bare TiO2. CONCLUSION: The increased photocatalytic activity of TiEN new materials are predominantly related to a lower energy gap, enhanced visible light absorption, higher reactive surface area and improved charge separation of photoinduced electron–hole pairs. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

• HCNS@TiO 2 fabricated by nanocasting method and kinetically-controlled coating. • This engineered photocatalyst showed a valuable performance for CO 2 conversion. • The obtained CH 3 OH and CH 4 photoproductions are 11.3 and 4.6 μmol/gcat.h. • The tailored photocatalyst showed excellent stability during five subsequent runs. Hierarchical g-C 3 N 4 @TiO 2 hollow sphere with excellent photocatalytic activity for CO 2 reduction under the visible light was prepared by assembling TiO 2 shell onto the surface of hollow carbon nitride sphere (HCNS). This engineered photocatalyst was prepared by a two-step process: at first, the process of nanocasting was done by a templating method, followed by the kinetically-controlled coating technique. Specifically, mesoporous silica sphere and cyanamide were used as sacrificial template and precursor of carbon nitride, respectively, for the synthesis of hollow carbon nitride sphere which was further modified with titanium dioxide nanosheets. The remarkable photocatalytic activity of as-prepared nanocomposite could be attributed to its special structure, providing properties such as light-harvesting, multiple light reflection and enhanced active site. Owing to the synergistic effect between g-C 3 N 4 and TiO 2 ; the light absorption region has been enhanced, leading to the improvement of photocatalytic performance. The obtained CO 2 photoreduction efficiency of HCNS@TiO 2 nanostructure is 11.3 μmol/g cat.h, which is about 5 and 10 times higher than the corresponding values for pristine g-C 3 N 4 and p-25, respectively. [ABSTRACT FROM AUTHOR]

Photocatalysis is one of the most promising advanced oxidation processes due to the capability of solid catalyst to continuously produce oxidant species under light irradiation. The use of conventional UV lamps is high cost intensive, which undermines the possible implementation in developing countries. Visible light active photocatalysts can overcome these challenges and find a market opportunity for competitive technology implementation. This work proposes the synthesis of visible light active catalyst following a facile sol-gel synthesis that introduces CuSO4 as dopant in TiO2. Results present complete abatement of methylene blue in 120 min of treatment under 50 mW cm−2 of blue light (λ = 450 nm), while commercial P25 TiO2 presented null abatement under identical conditions. Synthesis parameters including dopant level and calcination temperature allowed defining optimum synthesis conditions based on material characteristics modification and catalytic activity enhancement. A doping level of 0.21 mol% CuSO4 was identified as optimum condition to enable visible light photocatalysis of doped TiO2 catalysts calcined at 300 °C. Finally, operational parameters were evaluated defining a wide range of pH operation under 3.0 g L−1 of catalyst dose to treat up to 20 g L−1 of highly recalcitrant phenothiazine dye. These optimum conditions allowed complete dye removal under visible light after 120 min of treatment. [ABSTRACT FROM AUTHOR]

The loading of co-catalyst is an efficient way to increase the activity of synthesized carbon-based photocatalysts in the energy and environmental applications. Herein, Co and Ni decorated on g-C3N4 was synthesized as a visible light active photocatalyst and characterized with XRD, FT-IR, BET, DRS, TGA, FE-SEM, EDX, and EIS techniques. From the characterization results, it was demonstrated that cobalt and nickel which were present in the structure of the nanocatalyst, were in the metallic form. The decoration of Ni and Co reduced bandgap energy of g-C3N4 and made the synthesized nanocomposite active under visible light. The operating condition of O2 photocatalytic generation was optimized (193.75 μmol L−1 O2 productions using 0.2 g Co2Ni1/g-C3N4/rGO at 7 h without sacrificial reagents). The effect of sacrificial reagents (Fe(NO3)3, AgNO3, and methanol) was investigated and Fe(NO3)3 showed the best results during water oxidation. The kinetics study indicates that the presence of cocatalysts could be helpful in reducing the apparent activation energy about 3.5 times. The photocatalyst represented acceptable stability (2% Ni and 3% Co leaching) and reusability up to six cycles. According to the obtained results, we can introduce Co2Ni1/g-C3N4/rGO as a potential powerful photocatalyst for water oxidation reaction under visible light. Co and Ni are decorated on g-C3N4/rGO to synthesize a novel photocatalyst with a synergistic effect for photocatalytic water oxidation under visible light. The photocatalyst shows high stability and reusability after six cycles. [ABSTRACT FROM AUTHOR]

In order to remedy the shortcomings of narrow absorption wavelength range and low photogenerated carrier separation efficiency of TiO 2 photocatalyst, hydrochar (HC) was chosen to modify TiO 2 by constructing HC/TiO 2 heterojunction composite. HC/TiO 2 composites were synthesized from glucose, tetrabutyl titanate and deionized water by a simple one-pot hydrothermal way, and their photocatalytic Cr(VI) reduction properties were studied. The results indicated that HC/TiO 2 composites had tremendously improved photocatalytic Cr(VI) reduction activity, in comparison with TiO 2 , HC and a number of newly reported TiO 2 -based visible light photocatalysts. When the mass percentage of glucose to tetrabutyl titanate was 14, the obtained HC/TiO 2 -2 possessed the maximal photocatalytic activity, which was 19 times that of TiO 2 and 14.3 times that of HC under visible light (wavelength > 420 nm) irradiation, and 3.2 times that of TiO 2 under ultraviolet-visible light (Xenon lamp) irradiation. Furthermore, the photocatalytic stability of HC/TiO 2 -2 was also excellent. Additionally, proper choice of the photocatalysis experiment parameters could further raise the photocatalytic Cr(VI) reduction efficiency of HC/TiO 2 -2. The exceptionally elevated photocatalytic activity of HC/TiO 2 -2 was found to be due to its type-II heterojunction structure, which drastically heightened the separation and transfer efficiencies of photogenerated electrons and holes. Besides, HC/TiO 2 -2 also showed great potential for practical application in photocatalytic treatment of the Cr(VI) effluents discharged from freezing brine and black chromium plating industries. [Display omitted] • Facile one-step hydrothermal synthesis of hydrochar (HC)/TiO 2 composites. • HC/TiO 2 -2 had far superior visible light photocatalytic activity than TiO 2 and HC. • HC/TiO 2 -2 showed good performance in photocatalytic reduction of Cr(VI). • Reasons for the improved photocatalytic activity of HC/TiO 2 were proposed. • HC/TiO 2 -2 can treat the diluted freezing brine and black chrome plating solution. [ABSTRACT FROM AUTHOR]

Herein, we prepared a multifunctional BiPO 4 /TiO 2 /rGO (BTG) composite photocatalyst through a hydrothermal process and explored its structural and morphological characteristics through various characterization techniques. BTG displays an optimal adsorption-photocatalytic effect, which can remove 100% of malachite green (MG) and 88% of levofloxacin (LEO) in 3 h (BTG dosage = 0.67 g/L, initial MG and LEO = 20 mg/L, T = 298 K) through dark adsorption. Importantly, BTG exhibited enhanced degrading ability with 100% decomposition ration for MG and LEO after 45 and 165 min visible-light irradiation, which was 17.1 and 16.9 times that of neat BiPO 4 , respectively. Adsorption experiment, DRS, PL, Transient photocurrent and EIS analyses revealed that the multifunctional BTG composite not only demonstrated high adsorption capacity for MG and LEO, but also exhibited a narrow band gap energy, wide visible light absorption, efficient charge transfer and suppressed carrier recombination. In addition, the BTG also showed good stability towards the removal of MG and LEO with high removal efficiency throughout the 5 adsorption-photocatalysis cycles. Finally, the photocatalytic mechanism of MG and LEO by BTG was discussed based on free radical trapping experiments and Mott-Schottky measurements, which may give an idea for future design and construction of environmentally friendly adsorptive photocatalysts. [ABSTRACT FROM AUTHOR]

In the present study, we explored the effectiveness of PES-Ag3PO4/g-C3N4 film photocatalyst in degrading methyl orange dye under visible light irradiation. The PES-Ag3PO4/g-C3N4 film photocatalyst was prepared via a non-solvent-induced phase inversion process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser scanning microscopy (LSM), X-ray photoelectron spectra (XPS), UV-diffuse reflectance (DRS), and water contact angle. The incorporation of the Ag3PO4/g-C3N4 composite into the PES matrix improved the pristine PES film’s hydrophilicity, as evidenced by the reduction of water contact angle from 79.03° to 54.33° for a film containing 15 wt % of Ag3PO4/g-C3N4 composite. The film’s photoactivity showed that 13 wt % was the best loading of Ag3PO4/g-C3N4 composite, and the degradation performance was maintained up to three cycles. The •O2− and h+ were the predominant species responsible for the methyl orange degradation.

Photocatalysis with modified titania is a promising approach to improve both air and health quality. Modified titania with novel photocatalytic properties under indoor light irradiation leads to smart coatings, which are benchmark materials suitable for their indoor applications. It is generally accepted that the photocatalytic activity is affected by the light absorption, charge creation/recombination rate and surface reactivity. In this contribution we focus on modified TiO2 as catalyst in heterogeneous photo-catalytic processes and address the efficiency of TiO2-based building and construction materials on the removal of environmental pollutants indoors and outdoors. We also present data on the presence of eventually formed, toxicologically relevant and harmful by-products as the result of the photo-induced degradation of pollutants in an effort for better evaluation of induced risks for human health from the application of TiO2 modified materials. Finally, we present recent results on the disinfection performance of these material and the inactivation of severe pathogens contained in water and indoor air environments.

Rh nanospheres anchored TaON@Ta 2 O 5 with shell-core structure was synthesized from in-situ Rh3+-doped Ta 2 O 5 by one-step high-temperature ammonolysis, which exhibited efficient visible light photoactivity for H 2 -evolution (39.41 μmol·g−1·h−1), much higher than unmodified Ta 3 N 5 @Ta 2 O 5 (21.75 μmol·g−1·h−1). Rh-modifying inhibited the phase transformation from TaON to Ta 3 N 5 during the nitridation process, and increased the specific surface area and active sites, and extended the optical absorption throughout visible light region due to localized surface plasmon resonance (LSPR) effect. Relative intensities of peaks at 827 cm−1 for Ta–O bonds increased with increasing Rh-modifying amounts, which was beneficial to improving the stability. Notably, constructing novel Rh/TaON/Ta 2 O 5 heterojunctions including a Rh/TaON Schottky junction and an n-n TaON/Ta 2 O 5 mutant heterojunction facilitated photogenerated carriers directed transfer from inner to surface active sites, and decreased travel distance of charge carriers, and formed built-in electric fields to accelerating charge separation. Synergetic effects of the enhanced photocatalytic H 2 -evolution activity were discussed in detail. This work provided a promising strategy to further design and develop efficient and stable Ta-based photocatalysts for solar water splitting. Novel Rh/TaON/Ta 2 O 5 heterojunctions were constructed by combining Rh/TaON Schottky junction and n-n TaON/Ta 2 O 5 mutant heterojunction, which facilitated photogenerated electrons and holes directed transfer from inner to surface active sites, and decreased the travel distance of charge carriers, and formed built-in electric fields to accelerate the charge carrier separation. Image 1 • Rh nanospheres anchored TaON@Ta 2 O 5 was synthesized by high-temperature ammonolysis. • Reduction of Rh3+ and nitridation of Ta 2 O 5 were achieved via one-step ammonolysis. • Rh/TaON/Ta 2 O 5 heterojunctions containing a Schottky junction and an n-n mutant heterojunction. • A synergetic effect resulted in the enhanced photocatalytic H 2 -evolution activity. • Rh-modifying increased the specific surface area and active sites for H 2 -evolution. [ABSTRACT FROM AUTHOR]

Preparation and characterization of the Resin/Au-Pd bimetallic nanocatalyst. Photocatalytic degradation under visible light of parathion pesticide. Good catalytic activity after running 6 cycles without obvious decrease in the yield of reactions. In this work, Pd-Au nanoparticles supported on Amberlyst® resin (Pd-Au/Amberlyst®) as bimetallic photocatalyst with super adsorption performance, plasmonic effect, and fast interfacial charge migration was synthesized. The nano photocatalyst was characterized by FT-IR, ICP, XRD, FESEM, EDS mapping analysis, and TEM. Photocatalytic degradation under visible light of parathion as an organophosphorus pesticide by Pd-Au/Amberlyst® nanocomposite was studied. UV–Vis absorption spectroscopic technique studies were employed to investigate the performance of the nanocatalyst. This nanocatalyst has several fascinating advantages including easy preparation method, good catalytic activity, environmentally benign reaction conditions and was recovered with no considerable decrease in activity, it could be reused 6 times without obvious decrease in the yield of reactions. [ABSTRACT FROM AUTHOR]

• A comprehensive account on research activity for 2D inorganic nanosheets is presented. • 2D inorganic nanosheets can be used as valuable building blocks for hybrid photocatalyst. • Diverse examples of 2D inorganic nanosheet-based hybrid photocatalysts are presented. • In-depth discussion about the crucial roles of 2D nanosheets in photocatalysis is provided. • Future perspectives in researches for 2D nanosheet-based hybrid photocatalysts are discussed. Highly anisotropic 2D nanosheets of inorganic solids with nanometer-level thickness attract a great deal of research activity because of their unique merits in exploring novel high performance photocatalysts applicable for environmental purification and production of renewable clean energy. The 2D inorganic nanosheets possess many valuable properties such as tailorable band structures and chemical compositions, large surface areas, well-defined defect-free surface structure, and tunable electrical conductivities. Due to these unique advantages of 2D inorganic nanosheets, these materials can be used as promising building blocks for hybrid-type photocatalysts with optimized band structures, expanded surface areas, improved charge separation behaviors, and enhanced reaction kinetics. Of prime importance is that unusually strong electronic coupling can occur between very thin 2D inorganic nanosheets and hybridized nanospecies, leading to the synergistic optimization of electronic and optical properties, and thus the remarkable enhancement of photocatalytic activity. Depending on the type of component nanosheets, diverse examples of inorganic nanosheet-based photocatalysts are presented along with the in-depth discussion about critical roles of inorganic nanosheet in these hybrid photocatalysts. Future perspectives in the researches for 2D inorganic nanosheet-based photocatalysts are discussed to offer useful directions for designing and synthesizing novel high performance photocatalysts applicable for renewable energy production and environmental purification. [ABSTRACT FROM AUTHOR]

More than 2.6 eV band gap reductions were realized on a wide band gap semiconductor Mg 4 Ta 2 O 9 by nitrogen doping. The nitrogen doped Mg 4 Ta 2 O 9 , i.e. Mg 4 Ta 2 O 9-x N y , shows promising photocatalytic activities for both water reduction and oxidation under visible light illumination (λ ≥ 400 nm). • 2.64 eV band gap reductions have been achieved on Mg 4 Ta 2 O 9 doped with N. • Surface hydrophilicity has been improved by N doping. • Mg 4 Ta 2 O 9-x N y is visible light active for photocatalytic H 2 and O 2 production. • Flat band potential of Mg 4 Ta 2 O 9 is nearly unchanged after N doping. • N doping leads to uplift of valence band edge. Band gap engineering on wide band gap semiconductor photocatalysts is of critical significance in improving their solar energy utilization. Here, we have successfully realized large band gap reduction and visible light photocatalytic water splitting on a wide band gap semiconductor Mg 4 Ta 2 O 9 by nitrogen doping. More than 2.6 eV reductions in band gap have been achieved after doping nitrogen into Mg 4 Ta 2 O 9 , which strikingly red-shifts its absorption edge from less than 300 nm to as far as 600 nm. The nitrogen doped Mg 4 Ta 2 O 9 , i.e. Mg 4 Ta 2 O 9-x N y , shows promising photocatalytic activities for water reduction and oxidation under visible light illumination (λ ≥ 400 nm). Apparent quantum efficiency as high as ∼1.57% has been achieved at 420 ± 20 nm which is comparable to a number of active metal oxynitride photocatalysts. Photoelectrochemical analysis suggests that this band gap reduction stems mainly from an uplift of valence band edge position along with nitrogen doping. Our band gap engineering on a compact corundum type compound implies that nitrogen doping can be applicable to a wider range of metal oxides, not necessarily limited to those with an 'open' crystal structure (tunnels or layers, etc.) reported in the literatures, thereby opening new possibilities in searching and developing visible light active photocatalysts. [ABSTRACT FROM AUTHOR]

How to efficiently utilize visible light and highly separate photo-induced charges is now a hot topic in the field of photocatalysis. Herein, various amounts (1–5%, wt%) of Ag nanoparticles were selectively deposited on the surface of the polar material Na 3 VO 2 B 6 O 11 (NVB) via the method of photoreduction. Due to the presence of external screening effect, the Ag nanoparticles were selectively deposited on the positive domains of NVB materials. Through DFT, the (110) facet with excessive electrons accumulated has a high reduction ability to deposit the Ag nanoparticles on the edge of NVB crystals. It was also found that the surface plasmon resonances effect of Ag nanoparticles led to the absorption spectrum of NVB broadened to the visible range around 400–800 nm. Under visible light irradiation, the photodegradation efficiency of NVB was significantly enhanced with the 4% Ag deposition, which reached 96% for 2-Chlorophenol (2-CP) degradation in 100 min. It indicates that the screening effect of NVB combination with the surface plasmon resonances effect from Ag nanoparticles can provide a synergistic effect on the enhanced photocatalytic activity during the 2-CP degradation. Unlabelled Image • Visible light responsive photocatalytic materials Ag/Na 3 VO 2 B 6 O 11 were constructed successfully. • Internal polar domains from ferroelectric NVB can serve as driving force to enhance carrier separation. • Ag/NVB exhibited higher separation efficiency of the photo-generated carriers. • Synergistic effect of Ag/NVB was attributed to the superior photocatalytic activity. [ABSTRACT FROM AUTHOR]