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This study aims to elucidate the possible application of cobalt aluminate nanoparticles (CoAl 2 O 4) as a photocatalyst for the removal of organic dyes. The sol-gel method was employed to synthesise Nd x /CoAl 2 O 4 nanoparticles with varying weight percentages (x = 0.0, 0.2, 0.4, and 0.6 wt %). The experimental investigation focused on the photocatalytic destruction of colour, employing a visible light irradiation source. The structural and optical properties of the synthesised nanoparticle were examined through various analytical techniques, including X-Ray Diffraction (XRD), Ultra Violet-Diffuse Reflectance Spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), Tunnelling Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The cubic spinel structure was confirmed through the study of the X-ray diffraction (XRD) pattern of the Nd x /CoAl 2 O 4 nanoparticles. For the compositions x = 0.0, 0.2, 0.4, and 0.6, the nanoparticles exhibited average crystallite sizes of 23.73, 22.99, 21.69, and 21.65 nm, respectively. The synthesised nanoparticle exhibited heterogeneous photocatalytic potential when employed as a model pollutant for the oxidative destruction of crystal violet dye. The experimental findings validated that the CoAl 2 O 4 nanoparticle exhibited a dye degradation rate of 64 % during a 100-min timeframe. Additionally, the 0.6 wt % Nd CoAl 2 O 4 nanoparticle shows a quick dye degradation rate of 91 % for crystal violet dyes when exposed to visible light sources. Hence, the synthesised nanoparticle exhibits catalytic activity and holds potential for utilisation in the treatment of hazardous contaminants in industrial wastewater. [ABSTRACT FROM AUTHOR]

Well-constructed photocatalysts with efficient catalytic activity have attracted much attention due to their efficient visible-light absorption and superior charge separation capability. Visible-light responsive Cu 3 Mo 2 O 9 nanoparticles are synthesized utilising a simple and environmentally friendly green combustion process with Butea monosperma leaf extract as a reducing agent. X-ray diffraction pattern confirms the formation of orthorhombic crystal structure of Cu 3 Mo 2 O 9 NPs corresponding to space group Pnma (62). Furthermore, the synthesized NPs were characterized using FTIR, UV-DRS, PL, SEM and TEM studies. It was found that the direct energy band gap was 2.29 eV. Through photodegradation in the presence of visible light, the dye-sorbed photocatalyst exhibited excellent results. The sorbents have also been examined for recycling, and it has been observed that they maintain their effectiveness even after multiple successive runs. These substances therefore appear to have potential as efficient industrial dye wastewater remediators. Moreover, the high intensity emission in the green zone is amply confirmed by the photoluminescence emission spectra and CIE coordinates. The Latent fingerprints (LFP) are visible with the application of the powder dusting process. The synthesized CMO nanoparticles exhibit ridge patterns that are well-resolved and useful for identifying unique LFP. [ABSTRACT FROM AUTHOR]

Fabrication of efficient perovskite photo-Fenton catalytic systems is recognized as an effective strategy for clean water production. However, modifying perovskite catalysts effectively remains a formidable challenge. In this study, we prepared Bi-doped LaFeO 3 photo-Fenton catalysts using a facile microwave-assisted method. Various characterization techniques confirmed the successful formation of these Bi-doped LaFeO 3 perovskite materials. The photo-Fenton activity of the Bi-doped LaFeO 3 perovskite materials with varying Bi content was assessed by monitoring the degradation of methylene blue (MB) dye solution. Remarkably, the optimized Bi-doped LaFeO 3 (referred to as LBFO3) catalyst achieved approximately 93.64% degradation of MB within 100 min of visible light exposure, demonstrating exceptional efficacy in treating wastewater containing organic dye pollutants. The enhanced photocatalytic activity of the LBFO3 perovskite materials arises from the incorporation of Bi, leading to an expanded optical absorption range, increased specific surface area, and enhanced separation and migration of photo-generated carriers. Importantly, the LBFO3 photo-Fenton system exhibited remarkable stability during four successive cycling treatments, indicating promising practical applications. Additionally, quenching experiments were conducted to elucidate electron transfer in the LBFO3 catalyst related to the photo-Fenton degradation mechanism of MB. This study might pave the way toward designing novel perovskite based photo-Fenton systems for highly efficient degradation of waterborne contaminants. [ABSTRACT FROM AUTHOR]

Wastewater remediation is a major issue that threatens the ecosystem and health of human population and hence deserves our undivided attention. Dye effluents, in particular those comprising organic colourants from a number of industrial sites, are a major source of wastewater pollution that poses serious dangers to human health and the environment today. Therefore, the goal of this study is to eliminate these coloured effluents, which are present in substantial amounts in wastewater, either singly or in mixtures. In this respect, we present an easy sol-gel synthesis of CoFe 2- x Cr x O 4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) nano-ferrites for use as efficient photocatalysts. P-XRD technique was used for the confirmation of cubic spinel nanostructures having crystallite sizes in the nano-regime. Also, the optical band gap values resulted from Tauc plot indicates that incorporation of Cr3+ significantly reduces the band gap values. All the Co–Cr nano photocatalysts can be easily separable using an external magnet as indicated by the magnetic studies. For exploring the photocatalytic activity by photo-fenton process, we chose Rhodamine-B (RhB) as a model dye pollutant. Surprisingly, Cr3+ substitution into cobalt ferrite resulted in a dramatic transformation of the inert CoFe 2 O 4 into a highly visible light active photocatalyst for organic pollutant degradation. The CoFeCrO 4 nanocatalyst showed excellent results for the removal of RhB i.e., 99% removal in 30 min as compared to the CoFe 2 O 4 which was found to be inactive for the degradation. As a result of these exciting photocatalytic results, we were further encouraged to extend the degradation of a few other organic dye contaminants such methylene blue (MB), methyl orange (MO) and the mixture all three dyes (RhB + MB + MO). It was found that CoFeCrO 4 photocatalyst efficiently and swiftly degrades all three dye contaminants individually or in mixture with excellent recyclability and durability. [ABSTRACT FROM AUTHOR]

In this work, α-MnO 2 /BiVO 4 nanocomposites with varying MnO 2 contents (0–7 wt%) were successfully prepared via the simple chemical method. The structure, morphology, and optical properties of prepared nanocomposites were studied by various analytical techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible absorption spectroscopy, and photoluminescence (PL) spectroscopy. The photocatalytic efficiency of α-MnO 2 /BiVO 4 nanocomposites was studied via decomposition of rhodamine B (RhB) and tetracycline (TC) under exposure to visible light (λ ≥ 420 nm). Due to good structure and composite advantages, 5%MnO 2 /BiVO 4 (MnBV-5) photocatalyst exhibited superior RhB and TC degradation efficiency to all other samples. In addition, the MnBV-5 photocatalyst showed good stability, and no apparent reduction in photocatalysis efficiency was noted after five testing cycles. Therefore, the MnO 2 /BiVO 4 nanocomposite demonstrated a good potential for photocatalytic decomposition of new water contaminants. [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]

Facile preparation route for cobalt tungstate (CoWO 4) via cost effective, time saving, easy and solution combustion approach is described in the present paper. The structural, morphological properties of cobalt tungstate characterized by different physiochemical techniques which include X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray absorption (EDS). The optical properties assessed by UV–visible spectroscopy (DRS) and photoluminescence spectroscopy (PL). Using these methods, it was discovered that CoWO 4 which has been synthesized displayed a monoclinic phase of Wolframite with great crystallinity and purity. The average crystallite size of prepared CoWO 4 was 22 nm and band gap obtained was 2.84 eV due to which it can be used as visible light photocatalyst in aqueous medium. As a result, in this study, the photocatalytic degradation ability of CoWO 4 was assessed by observing the aqueous phase degradation of the most widely used dyes, methylene blue (MB) and Rhodamine-B as well as Cr(VI) reduction under visible light. Almost all MB degraded in 90 min whereas 69 % degradation of RhB takes place in 240 min under visible light irradation. The different aspects for low rate of photodegradation of RhB dye than MB dye was also discussed in this report. The present study deals advanced approach that CoWO 4 can also be used as capable visible light photocatalyst for degradation of dangerous contaminants and for reduction of carcinogenic Cr(VI) into nontoxic Cr(III) from waste water. [ABSTRACT FROM AUTHOR]

In this study, BiOBr microspheres were successfully synthesized through a facile solvothermal route in the presence of glycerol. The photocatalysts were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The morphology of BiOBr-6, which was synthesized using glycerol, comprised flower-like structures with diameters of ∼2 μm, which were composed of two-dimensional flakes with the sizes of tens of nanometers. The photocatalytic activity of the optimized BiOBr-6 was evaluated through the photocatalytic degradation of rhodamine B, methylene blue, methyl orange, and chrome blue-black R under visible light irradiation. Within 60 min, the degradation rates of Rh B、MB and MO reached 99.7 %, 99.6 % and 98.1 %, and within 90 min，the degradation rates of C-R reached 98.0 %. We concluded that the highly visible-light-driven catalytic performance of the flower-like BiOBr sample was associated with its high surface area, porous structure, and low bandgap energy, as well as its unique microsphere morphology. The resulting BiOBr microspheres may serve as promising adsorbents and photocatalysts for the treatment of organic pollutants. • BiOBr-6 exhibited the excellent photocatalytic degradation efficiencies on organic dyes. • BiOBr-6 possess a large specific surface area. [ABSTRACT FROM AUTHOR]

Water pollution has become one of the major global issues, posing serious threat to both humans and aquatic life. The elimination of organic industrial pollutants from wastewater is currently a major area of research. Herein, we report for the first time a novel FeSe 2 /ZnO composite system for highly efficient removal of organic dyes under visible light. FeSe 2 /ZnO composites with varying mass ratios of FeSe 2 were successfully prepared through simple and low-cost chemical method. The physiochemical properties of the prepared FeSe 2 /ZnO composites were carefully evaluated and compared with those of pure ZnO rods and FeSe 2 flowers. UV–vis spectroscopy confirmed that the coupling of FeSe 2 with ZnO caused a significant improvement in the optical absorption of ZnO. The bandgap energies of FeSe 2 /ZnO composites showed a red shift with increasing the ratio of FeSe 2 flowers. The prepared samples were evaluated for their photocatalytic response against the removal of methylene blue dye. Compared to the pure FeSe 2 and ZnO, the composites displayed impressive photocatalytic performance. Among the prepared samples, composite with an optimum ratio of 75 wt% FeSe 2 revealed outstanding photocatalytic efficiency, making it a promising candidate for the removal of organic pollutants. [ABSTRACT FROM AUTHOR]

The multifunctional ternary magnetic core/semiconductor/noble-metal nanocomposites have received considerable concerns because they can realize the integration of photocatalytic degradation, surface-enhanced Raman scattering (SERS) detection and magnetic separation to target organic waste water. Herein, the Fe 3 O 4 /Cu 2 O/Au nanocomposites were prepared through wet-chemical and in-situ reduction reactions. The influence of content of Au nanocrystals immobilized on the surfaces of Fe 3 O 4 /Cu 2 O on the photocatalytic and SERS performance of Fe 3 O 4 /Cu 2 O/Au nanocomposites was investigated. Photoluminescence (PL) results showed that Fe 3 O 4 /Cu 2 O/Au nanocomposites possessed higher photocurrent response compared with Fe 3 O 4 /Cu 2 O nanocomposites. And Fe 3 O 4 /Cu 2 O/Au nanocomposites exhibited stronger absorption of visible light owing to the localized surface plasmon resonance (LSPR) effect of Au nanocrystals. Methylene blue (MB) and malachite green (MG) were chosen as the photocatalytic degradation and detection targets to verify photocatalytic property and SERS characteristic of Fe 3 O 4 /Cu 2 O/Au nanocomposites. Results indicated that the photocatalytic efficiency and SERS signal intensity of Fe 3 O 4 /Cu 2 O/Au nanocomposites were improved significantly along with the increase of Au contents. The universal applicability of Fe 3 O 4 /Cu 2 O/Au nanocomposites was also evaluated by detecting SERS signals of residue of MB in fish. Our work offers exciting opportunities to acquire the multifunctional material for SERS trace detection and photocatalytic elimination to organic pollutants and will have more hopeful prospects in efficient catalytic and highly sensitive detection applications. • Fe 3 O 4 /Cu 2 O/Au nanocomposites (NCs) were prepared by wet chemistry reaction process. • Effect of Au content on catalytic activity of Fe 3 O 4 /Cu 2 O/Au NCs was studied. • Mechanism of photocatalytic reaction of dyes by Fe 3 O 4 /Cu 2 O/Au NCs was investigated. • Fe 3 O 4 /Cu 2 O/Au NCs achieved integration of photocatalysis and SERS detection. • Limit of detection of Fe 3 O 4 /Cu 2 O/Au NCs for MB and MG was as low as 10−11 M. [ABSTRACT FROM AUTHOR]

Ti 3 C 2 MXenes were constructed via different strategies using HF-forming etchants or HF as etchants and were subsequently modified through alkalization to replace –F with O-containing terminal functional groups. Various analytical techniques were used to fully characterize all fabricated materials for confirming the formation of species with the desired morphologies and properties. ML-Ti 3 C 2 , etched with HF, presented a multilayered structure that made it resemble an accordion, while DL-Ti 3 C 2 , prepared using HF-forming etchants, was not completely etched, with some amounts of the parent compound's Al remaining in unformed vague laminated structures. ML-Ti 3 C 2 alkalization yielded ML-Ti 3 C 2 (OH) 2 , which was characterized by large amounts of O-containing functional groups and greatly enhanced porosity compared with that of ML-Ti 3 C 2. Methylene blue (MB) adsorption and photocatalytic degradation tests were then conducted to evaluate the functionalities of ML-Ti 3 C 2 (OH) 2 by putting it into direct application instead of being used as catalyst promoters. ML-Ti 3 C 2 (OH) 2 achieved adsorption–desorption equilibrium using MB in the dark within 30 min and 81.2% of MB was then selectively degraded over 120 min under simulated visible light irradiation. A possible degradation mechanism was proposed on the basis of the results of radical quenching experiments. This study offers a unique mechanism for directly applying MXene to the adsorption–photocatalytic degradation of organics in wastewater. For Preparation and regulation of two-dimensional Ti 3 C 2 T x MXene for enhanced adsorption-photocatalytic degradation of organic dyes in wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

• A superior FePc-gCN photocatalyst is proposed for multiple organic dye degradation. • Mechanical ball-milling was employed to prepare the composite photocatalyst. • Role of FePc:gCN weight ratio in improving catalytic activity are investigated. • 1:5 wt% of fepc and gCN produced highest (90 %) removal efficiency for mB. • Radical trapping experiment and DFT results revealed° OH and O 2 • − radicals played major role in degradation of MB dye. We present here a mechanochemical method for facile synthesis of Iron phthalocyanine (FePc)- graphitic carbon nitride (gCN) composite with varying weight ratio (1:1, 1:2.5, 1:5) of FePc and gCN. The photocatalytic efficiency of FePc-gCN composite for the elimination of various synthetic dyes, viz , Methylene Blue (MB), Congo Red (CR) and Eosin B (EB) in aqueous media were investigated under visible radiation. The sample with FePc:gCN weight ratio of 1:5 resulted in a removal efficiency of 90 % for MB and 75 % for EB, much higher than their individual counterparts. The synergistic interaction, less charge recombination, and smaller charge transfer resistance in FePc-gCN composite contributed to the superior catalytic performances as confirmed from the impedance spectroscopy and the photoluminescence spectroscopy. Moreover, first principle based DFT calculations on the O 2 adsorbed FePc-gCN heterostructure predicted a net transfer of | 0.11 e | charges from Fe to O atom, favoring the generation of super oxide (O 2 • −) radicals which contributes actively towards degradation of dye pollutants. [Display omitted] [ABSTRACT FROM AUTHOR]

Ni-doped γ-Bi 2 O 3 was successfully synthesized via a one-pot oil bath synthesis. The prepared materials were characterized by XRD, DLS, SEM, FT-IR, EDS, TEM, and XPS. The XRD patterns confirmed the pure phase formation of tetrahedral γ-Bi 2 O 3. The material was tested for the degradation of various organic dyes and exhibited outstanding efficiency and selectivity for the photodeterioration of Congo red compared to other organic dyes. Furthermore, different Ni percentages were doped to find the best possible photocatalyst for Congo red degradation, with the 2 % Ni-doped γ-Bi 2 O 3 exhibiting an improved performance. The photocatalytic degradation efficiency of Congo red reached 93 % after 80 min and was used for three consecutive cycles without a considerable decrease in activity. UV–visible DRS spectra and the Mott-Schottky plot were used to understand the energy diagram of the materials. The higher visible light absorption and charge separation efficacy of the photogenerated electron-hole pairs induced by Ni loading contributed to improved photocatalytic performance. This study introduces a novel method for synthesizing Ni-doped tetrahedral γ-Bi 2 O 3 microstructures with precisely controlled morphology for the selective degradation of Congo red dye. [Display omitted] • Ni-doped γ-Bi 2 O 3 was synthesized via a novel facile one-pot oil bath synthesis. • This is the first photocatalysis work using the Ni-doped γ-Bi 2 O 3 phase. • The material exhibited outstanding selectivity for the degradation of Congo red. • The efficacy of Congo red reached 93 % after 80 min with 2 % Ni-doped γ-Bi 2 O 3. [ABSTRACT FROM AUTHOR]

A novel photocatalyst composed of bismuth molybdate (Bi 2 MoO 6 , BMO) coupled with rhodium (Rh) nanoparticles was synthesized and evaluated for its efficiency in degrading dye contaminant under visible light irradiation. The BMO/Rh composite demonstrated a significant enhancement in photocatalytic performance, achieving a 40 % higher degradation rate of Rhodamine B (RhB) compared to bare BMO. Enhanced charge separation and reduced electron-hole recombination were primarily attributed to the synergistic effects introduced by the Rh nanoparticles. Extensive characterization techniques provided insights into the structural and mechanistic aspects of the photocatalyst. Stability tests confirmed that BMO/Rh maintained over 95 % of its initial activity after five consecutive reaction cycles, highlighting its durability. Scavenger experiments identified superoxide radicals (•O 2 -) and hydroxyl radicals (•OH) as the primary active species, contributing to the high efficiency of dye degradation. This study underscores the potential of BMO/Rh hybrids as sustainable and effective photocatalysts for environmental remediation. • Enhanced a BMO/Rh photocatalyst that improves dye degradation by 40 % under visible light. • Achieved improved charge separation with Rh nanoparticles, reducing electron-hole recombination. • Maintained over 95 % photocatalytic activity after five cycles, demonstrating high stability. • Quantified active radicals' roles in improving dye degradation efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using BPO 4 as a new type of boron source, B/BiOCl was synthesized by a simple chemical deposition method, and the doping of B improves the adsorption performance and charge hole separation efficiency of BiOCl. • The photocatalytic degradation rates of the new B/BiOCl for RhB, MB and BF is 1.7 times, 3.6 times and 8.35 times those of BiOCl, respectively. • The novel B/BiOCl exhibits good performance in photocatalytic reduction of carbon dioxide, and its CH 4 production was increased to 3.21 times that of BiOCl. In this study, a fresh boron-doped B/BiOCl was produced utilizing BPO 4 as the boron origin. When exposed to visible light, B/BiOCl demonstrated effective degradation of organic dyes like Rhodamine B (RhB), methyl blue (MB), and basic fuchsin (BF). Their degradation rates surpassed those of BiOCl by 1.7 times for RhB, 3.6 times for MB, and 8.35 times for BF, respectively. Furthermore, the introduction of boron into B/BiOCl notably enhanced its photocatalytic reduction capability towards carbon dioxide, leading to a 3.21-fold increase in CH 4 production compared to BiOCl. Analysis results revealed a homogeneous distribution of boron within BiOCl, thereby improving its efficiency in charge-hole separation and adsorption. Consequently, the photocatalytic performance of B/BiOCl was significantly augmented. [ABSTRACT FROM AUTHOR]

[Display omitted] • The TiO 2 / N -GQDs (TGs) composite with hollow urchin-like structure was prepared. • The TGs can effectively expand the absorption spectrum of TiO 2 to visible light. • The TGs composite can efficiently degrade waste organic dyes under visible light. • The TGs composite has excellent stability and reusability. In order to enhance the visible light catalytic activity of TiO 2 by broadening its photoresponse range, the TiO 2 / N -GQDs (TGs) composite catalysts with a three-dimensional hollow urchin-like structure were prepared by one-step hydrothermal method. The microstructure and photoelectric properties of the synthesized TGs composites were analyzed through a series of characterizations, and the performance in degrading organic dyes under visible light was investigated. The results demonstrated that the prepared composites effectively enhanced the visible light absorption spectrum of TiO 2 by forming heterojunction. The degradation efficiency of organic dyes could reach 95.71% under visible light irradiation for 1 h, which further increased to 99.39% after 2 h. Additionally, the photocatalytic degradation process could be effectively accelerated under acid conditions. After 5 cycles of testing, the degradation efficiency of TGs composites on organic dyes was hardly reduced, indicating that they had great visible light catalytic activity and significant reusability. [ABSTRACT FROM AUTHOR]

Designing of an effectual heterostructure photocatalyst for catalytic organic pollutant exclusion has been the subject of rigorous research intended to resolve the related environmental aggravation. Fabricating p-n junctions is an effective strategy to promote electron-hole separation of semiconductor photocatalysts as well as enhance the organic toxin degradation performance. In this study, a series of n-type NiAlFe-layered triple hydroxide (LTH) loaded with various ratios of p-type MoS 2 was synthesized for forming a heterostructure LTH/MoS 2 (LMs) by an in situ hydrothermal strategy. The photocatalysts were characterized by XRD, SEM&EDX, TEM, FT-IR, XPS, as well as UV–vis DRS. The photoactivity of photocatalysts was tested by the degradation of Indigo Carmine (IC) dye. The optimized catalyst (LM1) degrades 100% of indigo dye in high alkaline pH under UV light for 100 min. Besides, the degradation rate of LM1 is 15 times higher than that of pristine NiAlFe-LTH. The enhanced photoactivity is attributed to the synergistic effect between NiAlFe-LTH and MoS 2 as well as the p-n junction formation. [Display omitted] • A facile method for synthesizing heterostructure-LMs photocatalyst is suggested. • The best photocatalytic performance was found in LM1 samples for dye degradation. • Superior adsorptive-photocatalytic activity of LM1 was revealed under visible light. • Photocatalytic performance of LMs was effectively exhibited even at high pH over 11. • The recyclability and mechanism of photocatalysis of LMs was identified. [ABSTRACT FROM AUTHOR]

• Preparation of pure ZnO and new Li-doped ZnO, Ag-doped-ZnO and Ag-Li doped ZnO nanocomposites materials by sol-gel method and thoroughly characterized. • Photodegradation of organic dye pollutants such as acid red-1 and mordant orange-1dyes and textile wastewater under visible light irradiation. • Mechanistic studies established that the active species are hydroxy radials via several scavengers' studies. The study describes the preparation and characterization of pure ZnO, Li-ZnO (LZO), Ag-ZnO (AZO) and Ag-Li-ZnO (ALZO) nanostructures by sol-gel method, followed by their application as photocatalysts for the degradation of dyes acid red (AR1), mordant orange (MO1) and textile wastewater (TWW) under irradiation of visible light. The ALZO composite showed the highest photocatalytic efficiency among the tested samples with 95% degradation of dyes, which was three times higher than that of pure ZnO. The degradation reaction followed pseudo-first-order kinetics and the control trapping experiments corroborated the reactive species are hydroxyl radicals. The study also investigated the influence of various operational parameters on the photodegradation of dyes. The high photocatalytic efficiency of the ALZO material is mainly due to its highly porous structure with greater surface area, enhanced absorption of visible light, and a decreased recombination rate of electron-hole pairs. The ALZO catalyst had a band gap energy of 2.82 eV and exhibited the wurtzite ZnO hexagonal phase. The study highlights the effectiveness of doping metal oxides into semiconductor oxides to enhance photocatalytic activity and suggests the potential of the ALZO composite as a promising photocatalyst for dye degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of novel nanohybrids of g-C 3 N 4 /UiO-66 heterojunctions was synthesized. • The nanohybrids shows excellent activity in photocatalytic degradation of organic dyes. • Degradation rate of the nanohybrids is much faster than g-C 3 N 4 and UiO-66 alone. • The possible photocatalytic mechanism of RhB was proposed and confirmed. • DFT calculations were carried out to confirm the heterojunction structure and photocatalysis mechanism. In this research, a novel composite of typical Zr-based metal–organic frameworks (UiO-66) with porous graphitic carbon nitride (g-C 3 N 4) was prepared by an in-situ preparation method. The g-C 3 N 4 /UiO-66 nanohybrids (CNU-0.5chieved almost 100 % efficiency in the degradation of RhB (60 mg/L, 100 mL) within 70 min under visible light, which was 6.46 and 10.56 times faster than that of pure g-C 3 N 4 and UiO-66, respectively. The improved photocatalytic properties were attributed to the large surface area, enhanced optical adsorption ability and the creation of heterojunction between g-C 3 N 4 and UiO-66. The formation of the heterojunction structure enhanced the photoelectron transfer efficiency and reduced the recombination of electron/hole pairs. Furthermore, the trapping experiments showed that •O 2 –, h+ and •OH were the active species in the photodegradation process, with •O 2 – playing a dominant role. This study offers valuable insights into the preparation of MOF-based photocatalysts with exceptional effectiveness for the removal of contaminants in wastewater treatment. [ABSTRACT FROM AUTHOR]

Water, the most fundamental source of life, is contaminated by various organic pollutants, especially organic dyes from the dying industry. The photocatalytic degradation of malachite green (MG) was studied using a zinc-based metal-organic framework (Zn-BTC MOF) and ZnO. Thermally decomposing Zn-MOF synthesized ZnO and its structural and optical properties were analyzed using various spectroscopic techniques. This article focuses primarily on the wavelength-dependent photoluminescence properties of Zn-MOF and ZnO materials and their role in the photocatalytic degradation of MG dye in water. Zn-MOF and ZnO photocatalysts exhibited a photodegradation efficiency of approximately 99% after 40 min of visible light exposure. Based on kinetic experiments, the degrading efficiency of these catalysts followed pseudo-first-order reaction kinetics with a correlation of R2 = 0.99 and a rate constant of 0.031 min−1. This manuscript is helpful to researchers working on ZnO and Zn-MOF materials for photocatalytic and environmental applications. • Photoluminescence is an important and frequently reported property of Metal-Organic Frameworks (MOFs). • This communication is primarily concerned with the luminescence properties of Zn-MOF and ZnO materials. • Zn-MOF and ZnO role in the photodegradation of recalcitrants such as malachite green (MG) in water. • These catalysts displayed photodegradation efficiency of about 95% within 40 min. [ABSTRACT FROM AUTHOR]

• A modified reflux method was conducted to synthesize TiO 2 /MIL-100(Fe) composites. • TiO 2 /MIL-100(Fe) composites provide multifunction, including adsorption, photocatalytic and heterogeneous photo-Fenton reaction for removing organic dyes. • MIL-100(Fe) could be used as a supporter to fix TiO 2 and adsorb dyes due to its high specific surface area. • TiO 2 /MIL-100(Fe) composites could absorb visible light to conduct photocatalytic and heterogeneous photo-Fenton reactions simultaneously. • The kinetics analysis of dark adsorption and light reaction belonged to the pseudo-second-order model. Since TiO 2 photocatalysts were only ultraviolet-light-responsive and homogeneous photo-Fenton had some drawbacks in generating iron sludge, multifunctional TiO 2 /MIL-100(Fe) composites were synthesized to remove organic dyes under simulated solar light irradiation. Commercial TiO 2 and MIL-100(Fe) precursors were mixed in one pot using a modified reflux method in 12 h, 18 h, and 24 h to fabricate TiO 2 /MIL-100(Fe) with different weight ratios of the TiO 2 and Fe(NO 3) 2 precursors, including 0.07, 0.15, and 0.30. MIL-100(Fe) was used to efficiently distribute TiO2 and adsorb dyes due to its high specific surface area. Besides, TiO 2 /MIL-100(Fe) composites could absorb visible light to conduct photocatalytic and heterogeneous photo-Fenton reactions simultaneously. For the TiO 2 /MIL-100(Fe) composites (TF15-18), the individual kinetics analysis of removing organic dyes, including dark adsorption and light reaction, belonged to the pseudo-second-order model with the rate constants of 1.682 and 7.702 g·mg−1·min−1, respectively. The completed dye removal was achieved under 90 min dark adsorption and 180 min light reaction under the best conditions of pH=3.5 and 40 μL H 2 O 2 addition in 150 mL MB solution. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Utilization of density functional theory (DFT) and time-dependent DFT calculations to achieve significant NIR absorption. • Discovery of a significant red-shift in dyes based on isoindigo derivatives with thiophene as the π-spacer. • Identification of fluorene as an effective donating group in dyes, which reduces charge recombination rates. In this study, we employed density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to optimize near-infrared (NIR) harvesting dyes, gaining deeper insights into their structure–property relationship, particularly for dye-sensitized solar cells (DSSCs). Our focus was on fine-tuning electron-donating and withdrawing groups within D-π-A metal-free organic dyes to enhance NIR absorption and achieve visually transparent DSSCs. Our research revealed a significant redshift in dyes based on isoindigo derivatives, with thiophene (TII) as the π-spacer. Dyes incorporating fluorene as the donor group effectively mitigated charge recombination rates, a key challenge in low-bandgap molecules. Notably, the TII1 dye, combining a fluorene donor with a TII π-spacer, exhibited maximum absorption at 654 nm and transmitted substantial visible light (500–600 nm), making it suitable for use in visually transparent DSSCs. These findings underscore the potential of the TII1 dye in significantly advancing the development of visibly transparent DSSCs. [ABSTRACT FROM AUTHOR]

Wastewater containing organic dyes is harmful to the ecological environment and human health. Graphitic carbon nitride (g-C 3 N 5) is suitable for the photocatalytic degradation of organic dyes, but its photocatalytic activity is low due to several drawbacks. A series of Ag–CeO 2 /g-C 3 N 5 composites with different morphologies of Ag–CeO 2 have been prepared in order to improve the photocatalytic activity of g-C 3 N 5. The photocatalytic activities of the Ag–CeO 2 /g-C 3 N 5 composites were investigated using rhodamine B (RhB) as the target pollutant. When compared with Ag–CeO 2 spheres and g-C 3 N 5 , the charge separation efficiency and photocatalytic activity of the Ag–CeO 2 /g-C 3 N 5 heterostructure were significantly improved. The photodegradation rate of RhB using 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 was 96.5 %, while pure g-C 3 N 5 and Ag (1.50)-CeO 2 spheres was 30.8 and 9.9 %, respectively. This was attributed to the synergistic effect of the heterojunction comprised of Ag, CeO 2 , and g-C 3 N 5. As an electronic medium, Ag transfers electrons between g-C 3 N 5 and CeO 2 , which can promote electron-hole separation and improve the photocatalytic activity. The 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 composites also had fair photocatalytic stability and · O 2 − plays a dominant role in the RhB photodegradation process. In addition, the photocatalytic mechanism of 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 has also been described. [Display omitted] • Series Ag–CeO 2 /g-C 3 N 5 composites were synthesized with respective morphologies of Ag–CeO 2. • Loading Ag–CeO 2 on g-C 3 N 5 can improve the specific surface area and photocatalytic property. • The photodegradation to RhB of 50 wt% Ag–CeO 2 /g-C 3 N 5 composites can reach 96.5 % within 150 min. • The 50 wt% Ag–CeO 2 /g-C 3 N 5 composites have good photocatalytic activity and chemical stability. [ABSTRACT FROM AUTHOR]

In pursuit of the appropriate method for complete removal of organic effluents from surface water, Ag modified g-C 3 N 4 materials as a photocatalyst gained considerable attention. In this paper, Ag doped g-C 3 N 4 materials were prepared by a facile one-pot pyrolysis method. The synthesized photocatalysts were studied using different analytical techniques like XRD, HR-TEM, XPS, UV, FTIR, PL spectroscopy, etc. The prepared photocatalyst materials were used for the visible light photodegradation of IC dye as an organic pollutant and for self-cleaning applications. The obtained results indicate that the optimized Ag doped g-C 3 N 4 (CNA-1) sample exhibits 79.97 % degradation efficiency in 30 min with efficient self-cleaning performance. The enhanced photocatalytic activity of CNA-1 can be attributed to the incorporation of Ag, which plays a pivotal role in absorbing visible light. Furthermore, cycling tests were employed to evaluate the stability and reusability of material. The possible photocatalytic mechanism was proposed from trapping experiments. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Three structurally simple D-A-π-A dyes were synthesized for DSSCs. • The effects of electron donor groups on photovoltaic performance were investigated. • DSSC based on diphenylamine donor achieved the highest PCE of 5.01 %. • By co-sensitizing appropriate dyes, a PCE of 5.49 % was achieved. Three structurally simple metal-free organic dyes (C1 , C2 and C3) with D–A–π–A structure, having benzothiadiazole auxiliary acceptor, benzene π-bridge and cyanoacrylic acid anchoring group, were designed and synthesized for use in dye-sensitized solar cells (DSSCs). Diphenylamine, carbazole and phenothiazine were used as electron donor groups and their effects on the photovoltaic performance were investigated. It was found that C1 dye with diphenylamine donor has the longest maximum absorption wavelength and highest molar extinction coefficient, which is benefical for harvesting more photons and generating a higher photocurrent. Therefore, the DSSC based on C1 dye gives a power conversion efficiency (PCE) of 5.01 %, which is greater than those of C2 dye with carbazole donor (3.51 %) and C3 dye with phenothiazine donor (1.76 %). Finally, the co-sensitization of C1 and C2 exhibits a highest PCE of 5.49 % may be due to broader visible light absorption. [ABSTRACT FROM AUTHOR]

As competitive photocatalysts, Cu 2 O nanoparticles meet with severe photogenerated carries recombination and insufficient light absorption, leading to the poor photocatalytic performance. Herein, the truncated Cu 2 O-Au (CA) binary and Cu 2 O-Au-TiO 2 (CAT) ternary octahedra with Au nanoparticles (Au NPs), preferentially supported on the (110) and (100) planes of Cu 2 O, are synthesized for efficient photocatalytic degradation reactions. The photodegradation rates of MO of CA1 (Cu 2 O-Au containing 1 wt % Au) and CAT are as high as 95.61% and 96.5% under 60 min of visible light irradiation, respectively. On the one hand, the synergistic function of localized surface plasmon resonance (LSPR) of Au NPs and Schottky barrier accelerate the separation and transfer of photogenerated carriers. On the other hand, a Z-scheme electron transfer system is constructed in CAT to promote the photodegradation performance. According to the finite-difference-time-domain (FDTD) simulation result, there is a strong electric field enhancement at the contact sites between Au, Cu 2 O and TiO 2 , which accelerates the electron transfer to a large extent and separates the electron-hole pairs. Therefore, this work may provide an approach for the synthesis and applications of multiple heterostructure catalyst. [ABSTRACT FROM AUTHOR]

Cu 2 O nanoparticles have been anchored on the surface of Bi 4 O 5 Br 2 hollow nanocubes, and the resulting composites have been tested for the photocatalytic degradation of organic dyes under visible light. The as-synthesized composites are composed of Bi 4 O 5 Br 2 in the monoclinic phase and Cu 2 O in the cubic phase, both of which respond to visible light. The optimized Bi 4 O 5 Br 2 /Cu 2 O composite can decompose 95% of initial RhB and 99% of initial MB after 80 min illumination, which is significantly higher than those obtained on bare Bi 4 O 5 Br 2 and Cu 2 O photocatalysts. The charge transfer and separation dynamics in the Bi 4 O 5 Br 2 /Cu 2 O composite photocatalysts under excitation are proved to be superior compared to bare Bi 4 O 5 Br 2 in the electrochemical measurements. The enhanced performance of the Bi 4 O 5 Br 2 /Cu 2 O composite is attributed to the p-n junction formed between Bi 4 O 5 Br 2 and Cu 2 O, which inhibits charge recombination and facilitates effective charge separation. Lastly, it has been proved in the scavenger tests that superoxide radical is the most crucial active species in the photocatalytic degradation of RhB. [ABSTRACT FROM AUTHOR]

In this research, carbon nanotube (CNT)-modified plasmonic silver-strontium titanate (Ag@ SrTiO 3) nanocomposites for the degradation of the organic dye were prepared by the sol-gel method. The characterization of all products was carried out using the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption test (BET), field emission-scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS), and transient photocurrent (TPC) studies. It was found that the incorporation of Ag in and introducing CNT into the SrTiO 3 nanoparticles reduced the crystallite size to 21 nm and the band gap energy to 2.7 eV. The Reduced PL peak intensity, increased photocurrent value, and reduced charge transfer resistance approved that the Ag@SrTiO 3 @CNT nanocomposite had a greater charge transfer efficiency than other samples. The optimal dosage of the photocatalyst, for the complete degradation of 5 ppm of the methylene blue (MB) solution after 30 min of the visible light irradiation, was decided as 0.5 g/L. Besides, in the experimental environment, the Ag@SrTiO 3 @CNT sample illustrated the most significant photocatalytic performance of the degradation of methyl orange (MO) and Rhodamine B (RhB) dyes. The detailed mechanism and kinetics of the degradation procedure were clarified. Finally, the prepared system displayed increased stability and reusability in the entire cyclic degradation experiment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sb 2 MoO 6 nanoparticles were anchored over g-C 3 N 4 nanotube by a facile reflux method. • The binary photocatalyst illustrated the highest activity in degradation of various pollutants. • Activity was 88.4-folds premier than g-C 3 N 4 in tetracycline degradation under visible light. • Activity was 48.3-times superior than g-C 3 N 4 in RhB degradation under visible light. • The photocatalyst displayed activity of 21.8-times larger than g-C 3 N 4 in Cr (VI) photoreduction. The development of high-efficiency photocatalysts is an attractive strategy for pollutants degradation under visible light. Herein, novel photocatalysts are reported through coupling Sb 2 MoO 6 with g-C 3 N 4 nanotube (abbreviated as GCN nanotube) by a simple reflux method. Also, the nanocomposites were defined by applying various analyses. Under visible-light excitation, the GCN nanotube/Sb 2 MoO 6 systems had more photoactivity than g-C 3 N 4 (abbreviated as GCN) and the rate constant for RhB removal on optimal GCN nanotube/Sb 2 MoO 6 (30%) nanocomposite was 48.3 times premier than the GCN. Also, compared to the pristine GCN, the GCN nanotube/Sb 2 MoO 6 (30%) sample demonstrated supreme photoactivity towards tetracycline degradation and Cr (VI) photoreduction, which was 88.5 and 21.8 times higher than the bulk GCN, respectively. These impressive enhancements were attributed to the quick segregation of charge carriers, boosted visible-light absorption, and extended specific surface area. Moreover, the photocatalyst has enough activity after four successive cycles. Finally, a conceivable charges transfer route is presented through n-n heterojunction constructed between Sb 2 MoO 6 and GCN nanotube. [ABSTRACT FROM AUTHOR]

A novel cobalt-based coordination polymer generates superoxide radicals under visible light to accelerate photocatalytic degradation of organic dyes. [Display omitted] It is crucial to construct an effective photocatalyst for the removal of dyes from aqueous environments. In the present work, a novel cobalt-based coordination polymer was synthesized and characterized with the molecular formula [Co(ipa)(ptt)] n (Co-CP), (ipa = isophthalic acid, ptt = 5-(4-Pyridyl)-1H-tetrazole). In Co-CP , each cobalt ion is in a six-coordination mode and is connected to two adjacent ligands to form a three-dimensional network structure. Furthermore, Co-CP excellent degradation properties and can effectively degrade methylene blue (MB) and rhodamine B (Rh B) under visible light with degradation efficiencies of 84.3 % and 94.6 %, respectively. Additionally, its PXRD patterns and FTIR spectra remained consistent with the original complex after three cycles, which proved that it was very stable, and there was no significant decrease in degradation ability after three cycling cycles, indicating its excellent reusability. The photocatalytic degradation mechanism was subsequently rationalized through free radical trapping experiments and analysis the energy band structure of Co-CP. [ABSTRACT FROM AUTHOR]

• 3D hollow ZIF-67 MOF based photocatalyst with excellent photo-catalytic performance was synthesized. • The H-ZIF-67@PDA@TiO 2 sample exhibited strongest photo-current intensity. • The photodegradation kinetic follows the Langmuir-Hinshelwood (L-H) model. • Superoxide free radicals (•O 2 −) and hydroxyl radicals (•OH) were the primary and secondary reactive species during photo-degradation. Photocatalytic technology is considered the most promising green technology for the degradation and removal of organic pollutants. In this paper, an innovative multifunctional photocatalytic material has been successfully prepared. The zeolitic-imidazolate-framework-67 (ZIF-67) was first synthesized by an easy and green approach. Then, a polydopamine (PDA) mid-layer was incorporated on its surface via dopamine self-polymerization, which not only serves as a stable linking agent, but also increases the amount of visible light captured and reduces the recombination of photogenerated electron-hole pairs. After the hydrolysis and hydrothermal process of tetrabutyl orthotitanate, the TiO 2 nanoparticles were uniformly grafted on the surface, and finally, the hollow ZIF-67@PDA@TiO 2 was successfully obtained. The prepared H-ZIF-67@PDA@TiO 2 photocatalyst was characterized by various techniques, and further used for the photo degradation of a variety of dyes in wastewater in the presence of visible light. A degradation rate of almost 100% was achieved for Acid Fuchsin and Congo Red within 40 min, followed by Erythrosine B and Rose Bengal with a 99% degradation rate within 150 min. Moreover, the ZIF-67-based photocatalyst exhibited high stability and recyclability and maintained an excellent photocatalytic performance during continued cycling. Furthermore, the superoxide radical (•O 2 −) and the hydroxyl radical (•OH) were the primary and secondary reactive species during photodegradation. Overall, the excellent performance of this simple photocatalyst was clearly demonstrated, and its numerous advantages, such as low energy consumption, low cost, non-toxicity, and environmental friendliness, showing promising potential for its practical implementation. [Display omitted] [ABSTRACT FROM AUTHOR]

The effect of structural variation on the photovoltaic performances of the pristine dyes has been investigated. The higher J sc is obtained for the cells as result of stronger electron-donaing phenoxazine moieties integrated into the (A-π-D-π-A) 2 branches of the sensitizers. The increased V oc originated from the n-dodecyl linker (L) and the five anchors in the skeleton of dyes, which can form a compact dye-layer on TiO 2 surface thus retarding the charge recombination and the back reaction efficaciously. By comparison, the five-anchoring sensitizers exhibit superior photovoltaic performances with respect to the reference dye containing di-anchors. • Four pristine (D–π–A)-L 2 -(A–π–D–π–A) 2 dyes featuring five-anchors were presented. • The five-anchoring dyes showed superior performance than that of reference dye TD. • The effect of different donors and linkers on the performance of DSSCs was studied. • A PCE of 6.77% was achieved by TQ2 based cells originating from the higher V oc. Developing organic dyes with di-/multi-anchors has aroused increasing attention in recent years due to these dyes had many advantages in comparison with the analogues of single acceptor. Herein, four (D–π–A)-L 2 -(A–π–D–π–A) 2 dyes (TQ1 − 2, OQ1 − 2) along with a reference D−(π–A) 2 dye (TD), comprising phenothiazine/phenoxazine as a donor, thiophene as a π space, cyanoacetic acid as an acceptor and saturated n-hexyl/n-dodecyl as a flexible linker have been prepared and characterized. The correlative between the variation of structure and the optical, electrochemical properties in addition to photovoltaic performances of the dyes have been explored. Besides, the ultraviolet–visible spectra in solution and on the TiO 2 film, cyclic voltammetry, photocurrent - voltage scan, incident photon-to-current conversion efficiency and electrochemical impedance spectroscopic of the presented dyes have been investigated. Compared with the reference dye TD , TQ1 − 2 and OQ1 − 2 exhibit higher molar extinction coefficient, broader and stronger incident photon-to-current conversion efficiency response spectrum, and higher density of light-absorbing units adsorbed on the TiO 2 surface. Among the cells based on the pristine dyes, the relatively high photocurrent of OQ1-2 by comparison with the counterparts of TQ1 − 2 is attributed to the incorporation of phenoxazine donor into the (A–π–D–π–A) 2 units. An increase open-circuit voltage of TQ2 and OQ2 compared to TQ1 and OQ1 is ascribed to the higher charge recombination resistance and the longer electron lifetime in their cells. Consequently, a maximum power conversion efficiency of 6.77% is attained by the TQ2 -based cells with iodide/triiodide electrolyte under the illumination of 100 mW cm−2. [ABSTRACT FROM AUTHOR]

• Novel TiO 2 QDs/BiOBr/BiOCl nanocomposites as efficient photocatalysts are reported. • The TiO 2 QDs/BiOBr/BiOCl (30%) nanocomposite exhibited the highest activity. • Activity was 176-folds greater than TiO 2 in RhB degradation under visible light. • The nanocomposite displayed substantial activity in removal of different pollutants. BiOBr and BiOCl were decorated on TiO 2 QDs through n-p-p heterojunctions by a simple strategy and they were applied for degradation of three organic dyes upon visible illumination. The obtained photocatalysts were analyzed via XRD, FESEM, EDX, UV–vis DRS, PL, BET, TEM, HRTEM, FT-IR, EIS, XPS, and transient photocurrent measurements. The TiO 2 QDs/BiOBr/BiOCl nanocomposite with 20% wt. of BiOBr and 30% wt. of BiOCl displayed superior photoability in the degradation of methylene blue, rhodamine B, and fuchsine, which was almost 34.5, 176, and 78.7-times larger than TiO 2 and 27.8, 13.5, and 51.5-folds greater than TiO 2 QDs, respectively. The results show that the construction of intimate n-p-p heterojunctions between BiOBr, TiO 2 QDs, and BiOCl counterparts leads to enhanced visible-light harvesting and improved charge separation, resulted efficiently increased photocatalytic activity. The trapping results proved that h+, •O 2 −, and OH• species have considerable effects on the degradation reaction. We think that the improved efficiency of the ternary TiO 2 QDS/BiOBr/BiOCl photocatalyst is a splendid alternative for the removal of toxic contaminants from wastewater. [ABSTRACT FROM AUTHOR]

The g-C 3 N 4 /ZnO nanorods were prepared by simple hydrothermal, grinding and calcination methods. The characterization of g-C 3 N 4 /ZnO nanorods was done by different analytical techniques such as SEM, TEM, XRD, XPS, FT-IR and UV–Vis. g-C 3 N 4 /ZnO nanorods with heterostructures have been successfully synthesized without changing the structure between the monomers, which broadens the visible light response range and improves several major pollutants in water degradation rate. Photocatalytic studies were done for the degradation of MB, RhB, Cr(VI) and eosin which are almost fully degraded. The experimental results show that the photocatalytic performance of the nanorods is much better than others. The g-C 3 N 4 /ZnO photocatalyst has excellent stability and repeated cycle performance. Basing on the results of comprehensive free radical trapping test and ESR tests, it is proposed that the main active substance of the catalyst for degrading dyes is ·0 2 -, and ·OH played significant roles in the degradation process. A good photocatalytic mechanism has been proven. [ABSTRACT FROM AUTHOR]

Perovskite type materials have high potential photocatalytic application towards both hydrogen energy generation and organic dye degradation due to their high stability and good reusability. Here, it is the first analysis of photocatalytic degradation of RhB and hydrogen energy evolution under visible light over MoS 2 /LaFeO 3 nanocomposite. The physicochemical properties of the materials were characterized using a range of techniques such as XRD, TEM, XPS, FTIR, PL, photocurrent, etc. The optical properties of the nanocomposite show good absorption in UV-Vis spectra as compared to the bare LaFeO 3. In this study, MoS 2 /LaFeO 3 nanocomposite was synthesized through single step in situ hydrothermal processes with a narrow bandgap, enhanced photocatalytic application under visible light. This novel MoS 2 /LaFeO 3 nanocomposite is an efficient and promising photocatalyst for both hydrogen energy evolution and organic dye degradation. MoS 2 /LaFeO 3 solid-solid interface showing enhanced hydrogen production and Rhodamine B degradation ability under visible light irradiation. Image 1 • An approach to fabricate MoS 2 /LaFeO 3 composite for water reduction and RhB degradation. • MoS 2 /LaFeO 3 composite was synthesized through a single step in situ hydrothermal process. • A composite synthesized with a narrow band gap, enhanced photocatalytic application. • Activity is due to interfacial interaction among MoS 2 and LaFeO 3 through self-assembly approach. [ABSTRACT FROM AUTHOR]

• Uniform and smooth Cu(0)-loaded polymeric fibers were prepared by one-step electrospinning. • Microwave Ar plasma treatments allowed to generate Cu/Cu 2 O nanostructures on fibers. • Various morphologies of Cu/Cu 2 O nanostructures were modulated by plasma treatments. • The plasma treated fibers displayed the highest photocatalytic activity toward methyl orange and 4-NP under visible light. Self-standing photocatalytic materials based on transition-metal decorated electrospun fiber mat have attracted considerable attention for photodegradation of toxic refractory organic pollutants in the environment. In this study, poly(N-vinylpyrrolidone)/copper(II) nitrate fibers (Cu/PVP-F) were prepared by electrospinning of PVP/Cu(NO 3) 2 solution followed by crosslinking using microwave-induced argon plasma (MAP) to produce Cu/Cu 2 O composites on the surface of fibers. The optimization for the electrospinning fibers was conducted such that the optimized electrospun composite fibers exhibited excellent visible light photocatalytic activity, corresponding to the narrowest band gap energy based on photoluminescence analyses. Moreover, the experimental results showed that the electro-spinning Cu/PVP-F fibers treated with MAP revealed the highest rate of photodegradation efficacy toward methyl orange (MO) and 4-nitrophenol (4- NP), that could be employed in the subsequent photocatalysis cycles with good recovery. [ABSTRACT FROM AUTHOR]

• A synergistic co-catalytic system was developed for improving photocatalytic activity. • A new photoredox reaction pathway based on organic molecular radicals was proposed. • Ultra-fast photocatalytic degradation of organic dyes was obtained. a new metal-free ternary composites based on organic molecular, N doped graphene quantum dots (N-GQDs) and g-C 3 N 4 was developed. The photocatalytic activity was evaluated for photocatalytic degradation of organic pollutant. It showed high photocatalytic degradation rate (ca. 0.25 mg/min) and ultra-short photocatalytic time (ca. 3.0 min) for complete degradation of organic dye (eg, RhB) in water. The enhanced photocatalytic performance was attributed to the synergistic effect of organic molecule and graphene quantum dots, enhancing visible light absorption, suppressing recombination of photogenerated charges and accelerating photoredox reaction of g-C 3 N 4. The study did not only propose a facile method to synthesis of free-metal photocatalysts with ultra-fast photocatalytic rate, but also represented a new method to improve the photocatalytic activity of photocatalysts based on carbon materials. [ABSTRACT FROM AUTHOR]

• Ni co-doped Al-ZnO photocatalyst was synthesized by high energy ball-milling method. • XRD, EDX and XPS measurements confirm the existence of Al and Ni in ZnO sites. • The photocatalytic activity of (Al, Ni) co-doped ZnO was evaluated by studying the degradation of MO and CR dyes. • A2 (2%Al, 2%Ni) co-doped ZnO was shown the highest catalyst activity amongst the series of ZnO. • Trapping experiments confirmed that the O2 were responsible for degradation of dyes. (Al, Ni) co-doped ZnO nanostructures were synthesized by a simple ball-milling method. The samples prepared were extensively characterized using standard techniques. X-ray diffraction analysis confirmed the coexistence of Al and Ni in the ZnO sites. The pollutant photodegradation performances of the materials were assessed by studying the removal of methyl orange and Congo red under visible-light illumination. Of the photocatalysts prepared, 2%Al-2%Ni-ZnO was found to be the most active for pollutant degradation, effecting 100% removal of MO within 30 min under visible-light illumination. This excellent catalytic activity was attributed to the strong absorption of visible light and effective separation of photoinduced charge carriers. In addition, radical-scavenging experiments were conducted to identify the key reactive species formed in the reaction, allowing a mechanistic rationale for the superior photocatalytic activity of 2%Al-2%Ni-ZnO to be proposed. [ABSTRACT FROM AUTHOR]

• The novel ternary Fe 2 O 3 /MoO 3 /AgBr photocatalyst was fabricated. • The heterostructure exhibited the best photocatalytic activity under visible light. • Effect of different experimental conditions were examined in organic dye degradation. • Photocatalytic mechanism was proposed, and confirmed by using various scavengers. In the present work, the novel ternary Fe 2 O 3 /MoO 3 /AgBr photocatalyst with different dosages of AgBr was successfully synthesized via a facile method. The physicochemical properties of the resultant catalyst were characterized by using various techniques such as XRD, SEM, EDX, BET, XPS, DRS, and VSM. The photocatalytic performance of as-prepared samples was evaluated by degradation of organic dye acid blue 92 (AB92) under visible light irradiation, and in dark. The impact of different operating parameters namely calcination temperature, amount of photocatalyst, dye concentration, and pH of solution were investigated in degradation reaction. Ternary nanocomposite exhibited the best photocatalytic activity due to synergistic effect between nanostructures, high visible light adsorption, and effective separation of charge carriers. The photocatalytic activity of this nanocomposite is about 7.1, and 5.1-fold higher than those of the Fe 2 O 3 , and Fe 2 O 3 /MoO 3 , respectively. The results displayed that the superoxide radical (O 2 · - ), and photo-generated hole ( h +) play the major role in the dye decomposition under visible light. The photocatalyst was easily separated from the reaction media by an external magnet, and used in five consecutive cycles without losing the activity, and stability. [ABSTRACT FROM AUTHOR]

• Mn or Fe doped CuO/ZnO were synthesized by co-precipitation method. • The ferromagnetism of CuO/ZnO nanocomposite enhanced by Mn and Fe doping. • Notable magnetization of 0.86 emu/g was found for 4 wt% Mn doped CuO/ZnO. • 4 wt% Mn induced superior visible light photocatalytic activity in CuO/ZnO. • Degradation efficiency of 98% with good recyclability was detected. Mn doped CuO/ZnO heterostructure exhibited significant room temperature ferromagnetism and visible light photocatalytic properties. Phase analysis for the pure, Mn and Fe doped CuO/ZnO nanocomposites evidently confirmed the formation of CuO and ZnO phases in each composite without any impurities. Based on Rietveld refinement analysis, the inclusion of Mn ions into CuO/ZnO nanocomposite decreased the unit cell volume of both oxides while Fe ions lead to lattice expansion. Mn ions induced the formation of ZnO hexagonal nanorods in CuO/ZnO nanocomposite. Nano-flakes and spherical nanoparticles shapes were seen for Fe doped CuO/ZnO nanocomposites. The characteristics IR absorption bands of CuO and ZnO overlapped together in their nanocomposites structure. From Kubelka-Munk plots, the incorporation of Mn ions enabled the ZnO band gap to absorb in the visible light region. Pure CuO/ZnO nanocomposite exhibited room temperature ferromagnetism with saturation magnetization (M s) of 0.042 emu/g and coercivity (H c) of 547 Oe. The ferromagnetic properties of the pure CuO/ZnO nanocomposite were greatly improved by Mn and Fe doping and the saturation magnetization extremely jumped to 0.86 and 0.85 emu/g, respectively. High photocatalytic activity, 98%, with good reusability for methyl orange (MO) degradation under visible light irradiation was achieved by 4 wt% Mn doped CuO/ZnO nanocomposite. A relation between the crystallinity, band gap and photocatalytic activity with dopant type (Mn or Fe) incorporated into CuO/ZnO nanocomposites was noticed. In contrary to Fe dopant, Mn as dopant played successful roles in improving the crystallinity, band gap and photocatalytic properties of CuO/ZnO nanocomposite. Multifunctional properties can be realized by combining different oxides in heterostructure form and using doping technique. [ABSTRACT FROM AUTHOR]

Photosensitization is a potential candidate for improving photocatalytic performance of inorganic semiconductors in water splitting. Given many photosensitizers are organic dyes bearing strong hydrophobicity, simple combination of dye and inorganic material, however, still suffers limited access of the photocatalyst to water and consequently presents compromised activity. Herein, we exploited aminated acid red-94 (RB-NH 2) to prepare dye chemically modified alginate (RB-NH-HA) via dialysis method, which was further employed to incorporate with CdS (RB-NH-HA@CdS). According to the water contact angles (CA water) and photoelectrochemical detection, though simply integrated CdS with RB-NH 2 (RB-NH 2 @CdS) expectantly enhanced the transient photocurrent over CdS, yet the CA water was apparently emaciated from 53.56° to 86.12°, even leading to a slightly attenuated photocatalytic performance in hydrogen evolution under visible light. In contrast, introducing hydrophilic HA into RB-NH-HA@CdS is able to reclaim the CA water to 50.22°. Moreover, owning to the cooperative effects proffered by the significantly increased contacts between the reactant (H 2 O) and the composite, as well as the fluorescent feature that improves the photocatalyst's visible-light absorption and simultaneously suppresses the recombination of photo-induced carriers, the hydrogen production rate was advanced to 475 μmol·h−1 H 2 , about 4.5 and 5.7 times that of CdS and RB-NH 2 @CdS, respectively. Our work provides an efficient method to ameliorate the sensitization technique aiming to improve the photocatalytic performance of inorganic semiconductors. An alginate-based polymer could effectively photosensitize CdS and present enhanced photocatalytic hydrogen evolution due to its improvement in wettability of the structure. Unlabelled Image • The hydrophilic alginate-based polymer RB-NH-HA was employed to improve the wettability of RB-NH 2 @CdS. • The RB-NH-HA takes dual effects of water miscibility and optical feature on the photocatalytic performance. • RB-NH-HA@CdS can give the hydrogen production rate of 475 μmol•h-1, about 4.5 times that of CdS. [ABSTRACT FROM AUTHOR]

• Prepared composite nanofiber membrane possesses a good photocatalyst performance. • High degradation activity of organic dyes under visible light. • The composite nanofibers membrane possessed excellent recovery and reuse. • The free-standing membrane is flexible and easy to handle. • The flexibility of the composite nanofibers allows use in a continuous operation. This study proposed an effective method by using photocatalytic composite nanofiber membranes in order to degrade malachite green (MG) and acid red 27 (AR 27) to harmless products. The photocatalytic composite nanofiber membrane, Polyacrylonitrile (PAN) was incorporated with catalyst SiO 2 and TiO 2 photocatalyst. The PAN/SiO 2 -TiO 2 -NH 2 nanofiber membrane was synthesized by electrospinning technique followed by chemical crosslinking. The results of SEM, EDX, FTIR and XRD confirmed the successful preparation of nanofiber membrane. XRD analysis shows the confirmation of SiO 2 and TiO 2 peaks. The result shows that PAN/SiO 2 -TiO 2 -NH 2 nanofiber membrane exhibit the highest degradation with a good distribution of SiO 2 and TiO 2 on the PAN nanofiber membrane surface. The results showed that the complete photodegradation of MG and AR 27 with artificial visible-light was achieved after 9 and 25 min, respectively. In addition, the nanofiber membrane exhibited good stability and reusability for MG and AR 27 photodegradation and has potential to be applied in industrial application. [ABSTRACT FROM AUTHOR]

Research over dye-sensitized hydrogen generation using TiO 2 semiconductor photocatalysts has gained abiding importance over the past three decades due to its manifold advantages over other photocatalytic systems for the production of clean energy fuels. The single-step excitation of the electrons over the sensitizer molecules anchored at the TiO 2 semiconductor serves as a driving source to facilitate the electron effect transfers, thus prompting the visible-light driven photocatalytic hydrogen generation activities. Though many review articles that evaluate the performance of such dye-sensitized semiconductor particulate systems are available in the literature, research progress made in the last few years since 2016 is not yet systematically reviewed. In this article, we therefore, systematically review the development of new dye-sensitizers that include metal-free organic dyes, metal-based sensitizers, and donor-bridged-acceptor (D-π-A) type dye-sensitizers, and their performances in sensitization of the TiO 2 semiconductor photocatalyst towards visible light driven hydrogen generation through water splitting. It has been chronicled that the aforesaid sensitizers are capable of harvesting a broader part of the solar spectrum, and could achieve photocatalytic H 2 production with varying degrees of success. The results discussed in this review afford a significant scope of rationalizating the factors that govern the H 2 production activity over the dye-modified TiO 2 photocatalyst, and provide a basis for further research towards the realization of high-performing dye-sensitized H 2 production photocatalytic system. The prospect of artificial intelligence (AI)-machine learning (ML) based modeling for quicker design and development of dye-sensitized TiO 2 based photocatalytic solar to fuel conversion system has been briefly discussed in the article. [Display omitted] • Dye sensitization of TiO 2 semiconductor for photocatalytic hydrogen generation. • Dye design strategy for harvesting broader spectrum of visible light. • Advancement of metal-free and metal-based organic dye-sensitizers. • Prospect of donor-π-space-acceptor type dye-sensitizers in hydrogen generation. • Prospect of dye-sensitization TiO 2 photocatalysts in solar to fuel conversion. [ABSTRACT FROM AUTHOR]

Flower-like zinc oxide nanoclusters were successfully incorporated by different amount of PTCDA organic dye molecular, forming the hetero-structured PTCDA/ZnO composites. Remarkably, a study performed on their NO 2 sensing properties reveals that the 0.5 wt% PTCDA-loaded ZnO sensor exhibits high response, excellent selectivity, quick response speed and low detection limit of 7.4 ppb towards NO 2 molecules at room temperature (25 °C) under green light illumination, which possesses an apparent advantage over the ZnO sensors loaded with other PTCDA concentration as well as upon other light illumination conditions. This work makes a meaningful contribution to the development of NO 2 sensor based on wide-band gap semiconductors with visible light irradiation. [Display omitted] • PTCDA-loaded ZnO composites were prepared with various loading contents. • S 3 exhibits superior NO 2 sensing property in green light at 25 °C. • The property is due to P-N heterojunctions in S 3 and the enhanced chemisorbed oxygen under green light. • Gas property is also due to high photoelectric conversion efficiency under green irradiation. [ABSTRACT FROM AUTHOR]

• Using cheap ethanolamine as raw material, an ingenious strategy was employed to prepare the Fe-and-N co-doped ZIF-derived catalyst, which not only effectively avoided the aggregation of active species, but also was conducive to spread application and promotion. • The dimension of nanostructure for the series catalysts are all uniform and small (∼100 nm), and it can still do plenty of advantages to the catalytic activity. • The highly uniform dispersed of Fe and N active sites not only broadens the visible light response range, but also greatly improve the photocatalytic performance of the materials, and almost 100% of the dyes were removed in just 25 min. The amino and iron modified Metal-organic frameworks was successfully synthesized via a skillfully strategy and used as a photocatalyst to decompose organic dyes under visible light irradiation. Results show that 50 mg catalyst can almost degrade 100% MB within just 25 min at a wide pH (3.4–11.9) range. The kinetics constant (k) on Fe-ZIF-8-NH 2 (1/10) is estimated to be 0.0896 min−1, significantly higher than control samples. Meanwhile, there is little effect of various water sources on catalytic activities, and the rate reaches 97.1% (in Tap water), 88.5% (in Yangtze River water) and 78.1% (in oilfield brine with ultrahigh mineralization). Besides, the Fe-ZIF-8-NH 2 (1/10) exhibits high stability after 5 cyclic runs, and the ICP detects a small amount of Fe3+ (0.153 mg/L) leaching. Characterization reveals the catalyst has hierarchical porous structure, a rather homogeneous geometric topology and uniformly dispersed active sites. Based on the N 1 s spectrum of XPS, the nitrogen group is successfully loaded in amino mode. Its band gap drops sharply from 5.11 eV to 2.17 eV and the peak of PL spectra is much smaller, and the Fe-ZIF-8-NH 2 (1/10) possesses stronger absorption in visible light region and the response wavelength is widened to 700 nm. Further, the possible mechanism of photocatalytic degradation of pollutants is also proposed. The h+ is the most effective active species, meanwhile, •O 2 − , e − and •OH are both apparently participated in the photodegradation process. This study introduces valuable information for constructing high active catalysts on administration of water pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a facial synthesis of α-MoO 3 nanoparticles was done by chemical co-precipitation method. The synthesized α-MoO 3 nanomaterials have been reported for sensing and photocatalysis applications together. For sensing, the α-MoO 3 was coated on FTO based interdigitated electrodes, and the prepared sensor was tested for numerous concentrations of ammonia (100–600 ppm) under different relative humidity levels (11–33%−56–75% −95% RH). The response and recovery time of α-MoO 3 based sensor for 500 ppm of NH 3 were 8 s and 11 s under 95% RH, respectively. The prepared α-MoO 3 based sensor exhibits high selectivity and stability towards ammonia. To analyze the photocatalytic activity of prepared α-MoO 3 nanoparticles, the photodegradation of methylene blue (MB) and methyl orange (MO) under visible light irradiation was studied. The first-order reaction rate constant for MB dye is 0.02434 min−1, and for MO dye is 0.01111 min−1. Finally, the maximum degradation efficiency for MB and MO dyes was calculated to be 95% and 73%, respectively. The given data conclude that the synthesized α-MoO 3 nanoparticles can be used as an effective NH 3 sensor as well as an efficient photocatalyst in organic dye degradation. [Display omitted] • The chemical co-precipitation technique was used to synthesize the hierarchical α-MoO 3 nanoparticles. • The sensor's selectivity, sensitivity, repeatability, and stability towards NH 3 were studied. • The relative humidity enhanced the performance of the NH 3 sensor. • Fast and efficient removal of methylene blue (95%) and methyl orange (73%) were investigated under visible light irradiations. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiO 2 with high exposure of (001) facet can be fabricated using solvothermal method. • Ultrasonic method was used to efficiently prepare TiO 2 (001)/GO composite. • Integration of GO and TiO 2 (001) successfully increased photoactivity of the material. • Methylene blue and crystal violet were efficiently photodegraded at visible range. • The exposure of TiO 2 ′s (001) was responsible for the enhancement of photoactivity. Photodegradation has been considered one of the most promising ways to treat wastewater. In this work, TiO 2 (001)/Graphene Oxide (GO) nanocomposite has been successfully synthesized using hydrogen fluoride as a crystal-directing agent towards (001) facets. The nanocomposite was characterized by FTIR, XRD, Raman, HR-TEM, and diffuse reflectance spectra (DRS). Based on the result, the TiO 2 (001) was decorated on the surface of the GO sheet with high absorption of visible light. In addition, as-prepared TiO 2 (001)/GO nanocomposite provides a synergistic effect by increasing dye degradation activity with 95% and 99% removal rates for the photodegradation of methylene blue and crystal violet dyes, respectively, under LED irradiation for 10 min. The photodegradation kinetics of TiO 2 (001)/GO was also successfully modeled and was found to follow the pseudo-first order kinetic. The enhanced photodegradation of the TiO 2 (001)/GO nanocomposite attributed to the excellent synergy between TiO 2 (001) nanoparticles and GO, which results in the highly efficient photocatalyst for removing organic pollutants in water. [ABSTRACT FROM AUTHOR]

The catalytic activity of photocatalyst is strongly dependent on the phase structures, grain size and particle morphology of the catalyst. In this paper, the controlled synthesis of bismuth(Bi) with different morphologies (nanoparticles, nanorods, nanocubes and micro-spheres) has been successfully realized by adjusting different experimental parameters. The Bi nanostructures were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), UV–vis absorption spectroscopy (UV–Vis). The PL spectra shown that the reduction of the size of Bi nanomaterials can decrease the recombination rate of photoelectrons and holes, which leads to the effective separation of photocharge carriers and the better photocatalytic performance of Bi nanomaterials. The energy gaps of Bi nanoparticles, nanorods, nanocubes and microspheres are 2.57 eV, 2.69 eV, 2.99 eV and 3.16 eV respectively. The degradation activity of Bi nanostructures with different sizes on organic dyes showed that 99.9%, 98.9%, 97% and 68.3% degradation of RhB was observed after 90-min visible light irradiation for Bi nanoparticles (20–50 nm), nanorods (20 nm in diameter and 1 μm in length) nanocubes (150–200 nm) and micro-spheres (10 μm), respectively. The results indicated that if the grain sizes of the Bi samples are reduced from micro-size to nano-size, their catalytic activities dramatically increase. At the same time, the achieved results also reveal that Bi 2 O 3 and BiOCl were found in Bi surfaces before and after catalytic degradation, which was confirmed by XPS and FTIR technology. In addition, the catalytic activity of Bi with the same morphology increased with the decrease of pH value. Furthermore, the Bi samples still retained excellent catalytic activity after 40 cycles, the removal rate could also reach 73.5% for the 40th cycling. • Bismuth with different morphologies was successfully synthesized. • Bismuth performed different catalytic activities at different pH values. • The catalytic activity increases as the decrease of bismuth size. • Bismuth retained excellent catalytic activity after 40 cycles. [ABSTRACT FROM AUTHOR]

The novel GdTaO 4 phase exhibits good photocatalytic activity under visible light irradiation and holds great promise for the removal of organic dyes from industrial wastes. The GdTaO 4 samples were synthesized using the hydrothermal and calcination process with different weight ratios of gadolinium nitrate hydrate (G) and tantalum pentachloride (T), and their structural studies confirmed the formation of the GdTaO 4 (GT) phase. Among the samples, GT-4 (with a weight ratio of 4:1) exhibited the highest photocatalytic activity for the degradation of Methyl Orange (MO) dye under visible light irradiation. To enhance the photocatalytic performance, H 2 O 2 was used as a green additive, and the photocatalytic abilities were examined by varying dye types and concentrations. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) revealed the local atomic and electronic structures around Ta and Gd and highlighted the contribution of Gd3+ to the GT system, which is a crucial factor in supporting the enhanced photocatalytic performance. Moreover, in-situ XAS at Gd M 5 -edge and O K-edge were examined under illumination/dark conditions to explore the electronic structures of photo-excited electron transition in the photocatalytic process. The analytical results provided strong evidence correlating the electronic structure and photocatalytic property of the GT. This study demonstrates that GdTaO 4 exhibits good photocatalytic activity under visible light irradiation, making it a promising new Ta-based photocatalyst for the effective removal of organic dyes from industrial wastes. [Display omitted] • GdTaO 4 photocatalysts are synthesized via hydrothermal and calcination processes with different Gd and Ta ratios. • Photocatalyst GT-4 exhibited the highest catalytic activity for MO degradation under visible light. • To enhance the Photocatalytic performance, H 2 O 2 was used as a green additive, assessing dye types and concentrations. • Ex-situ and in-situ XAS are crucial for understanding enhanced photocatalytic performance by revealing Ta and Gd local atomic/electronic structures. [ABSTRACT FROM AUTHOR]

A solvothermal method was used to synthesize the mesoporous TiO 2 , (1-3w %) Cu-doped mesoporous TiO 2 membrane with the help of a bioreactor. To understand the physicochemical composition of all synthesized nanomaterials, the structure, morphology and crystallinity of the materials were studied using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform-infrared (FTIR), Energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). Under artificial light source (500 W mercury bulb) irradiations, the nano catalysts' catalytic effectiveness was examined for the azo dyes, namely Congo red. Cu-doping causes a shift in the light absorption of mTiO 2 from the ultraviolet to the visible region. The 3w% Cu-doped mTiO 2 photocatalyst exhibits lower band gap energy (2.6eV) than TiO 2 which is 3.2 eV to efficiently utilize solar energy. As a result, the light absorption was shifted towards the visible spectrum. The recommended mTiO 2 and (1, 2, 3) w% Cu-doped mTiO 2 photocatalysts were used to photodegrade Congo red and methylene blue. For the degradation of CR, the mTiO 2 photocatalyst exhibited 61% and 3w% Cu-doped mTiO 2 demonstrated 99% photocatalytic performance after 50 min. A variety of scavengers were also utilized to distinguish the active species by catching the radicals and holes created during the process of photocatalytic degradation. CV indicates the presence of Cu2+ and Cu1+ in Cu-doped mTiO 2. Oxygen vacancies and the electronegative surface of Cu1+ seem to perform the photocatalytic reduction of CR. [Display omitted] • Cu-doped mesoporous TiO 2 based membrane using bioreactor. • A novel porous material membrane for Degradation of Dye. • Cu-doped mTiO 2 demonstrated exceptional photocatalytic performance (99%). [ABSTRACT FROM AUTHOR]