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The objective of this study is to create a planar solar light absorber that exhibits exceptional absorption characteristics spanning from visible light to infrared across an ultra-wide spectral range. The eight layered structures of the absorber, from top to bottom, consisted of Al2O3, Ti, Al2O3, Ti, Al2O3, Ni, Al2O3, and Al. The COMSOL Multiphysics® simulation software (version 6.0) was utilized to construct the absorber model and perform simulation analyses. The first significant finding of this study is that as compared to absorbers featuring seven-layered structures (excluding the top Al2O3 layer) or using TiO2 or SiO2 layers as substituted for Al2O3 layer, the presence of the top Al2O3 layer demonstrated superior anti-reflection properties. Another noteworthy finding was that the top Al2O3 layer provided better impedance matching compared to scenarios where it was absent or replaced with TiO2 or SiO2 layers, enhancing the absorber’s overall efficiency. Consequently, across the ultra-wideband spectrum spanning 350 to 1970 nm, the average absorptivity reached an impressive 96.76%. One significant novelty of this study was the utilization of various top-layer materials to assess the absorption and reflection spectra, along with the optical-impedance-matching properties of the designed absorber. Another notable contribution was the successful implementation of evaporation techniques for depositing and manufacturing this optimized absorber. A further innovation involved the use of transmission electron microscopy to observe the thickness of each deposition layer. Subsequently, the simulated and calculated absorption spectra of solar energy across the AM1.5 spectrum for both the designed and fabricated absorbers were compared, demonstrating a match between the measured and simulated results.

The photo-induced peroxymonosulfate (photo-PMS) reaction is a promising route to eliminate antibiotics from waste water. To achieve excellent photo-PMS activity in Mg–Fe layered double hydroxides (LDHs) for tetracycline hydrochloride (TCH) degradation under simulative solar-light irradiation, Mg–Fe LDHs-loaded polyacrylonitrile (Mg–Fe/PAN) nanofibers were in-situ prepared via the hydrothermal route. For comparison to the photocatalysis and photo-PMS process, the Mg–Fe/PAN-assisted photo-PMS process exhibited a better elimination activity for TCH elimination. In addition, the photo-PMS activities of Mg–Fe/PAN composites were greatly affected by Mg–Fe LDHs content, TCH concentration, pH, and inorganic salts. Among these Mg–Fe/PAN composites, the optimal MgFe2/PAN with a Mg/Fe molar ratio of 1:2 and a nominal Mg–Fe LDHs content of 2.0 wt. % removed 81.31% TCH solution of 80 mg L−1 TCH within 120 min. This enhanced photo-PMS capacity of MgFe2/PAN was ascribed to the abundant active sites formed by functional groups and oxygen defects for efficient TCH species adsorption and photon capturing, and the tight interface between Mg–Fe LDHs nanoparticles and PAN nanofibers for the rapid separation and transfer of photoinduced e−/h+ pairs. SO4•− and •O2− radicals were vital for the MgFe2/PAN-assisted photo-PMS reaction.

Z-scheme heterojunction Bi2WO6/g-C3N4 was obtained by a novel hydrothermal process; its photocatalysis–persulfate (PDS) activation for tetracycline (TC) removal was explored under solar light (SL). The structure and photoelectrochemistry behavior of fabricated samples were well characterized by FT-IR, XRD, XPS, SEM-EDS, UV-vis DRS, Mott-Schottky, PL, photocurrent response, EIS and BET. The critical experimental factors in TC decomposition were investigated, including the Bi2WO6 doping ratio, catalyst dosage, TC concentration, PDS dose, pH, co-existing ion and humic acid (HA). The optimum test conditions were as follows: 0.4 g/L Bi2WO6/g-C3N4 (BC-3), 20 mg/L TC, 20 mg/L PDS and pH = 6.49, and the maximum removal efficiency of TC was 98.0% in 60 min. The decomposition rate in BC-3/SL/PDS system (0.0446 min−1) was 3.05 times higher than that of the g-C3N4/SL/PDS system (0.0146 min−1), which might be caused by the high-efficiency electron transfer inside the Z-scheme Bi2WO6/g-C3N4 heterojunction. Furthermore, the photogenerated hole (h+), superoxide (O2•−), sulfate radical (SO4•−) and singlet oxygen (1O2) were confirmed as the key oxidation factors in the BC-3/SL/PDS system for TC degradation by a free radical quenching experiment. Particularly, BC-3 possessed a wide application potential in actual antibiotic wastewater treatment for its superior catalytic performance that emerged in the experiment of co-existing components.

Photocatalytic response of V2O5, ZnO, and V2O5/ZnO nanostructures for the degradation of Tubantin red 8BL dye has been reported. Pure V2O5, ZnO, and V2O5/ZnO composite nanostructures were synthesized through a hydrothermal method. UV–Visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray microscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) characterizations were done to examine their bandgap energy (Eg), morphology, composition, and structure, respectively. These discoveries advance our knowledge of the agglomerated nanoparticles of V2O5, ZnO, and V2O5/ZnO for their prospective photocatalytic uses. The presence of V2O5 and ZnO in composite is confirmed through the analysis of FTIR. Flower shaped morphology was observed in V2O5/ZnO nanocomposite by SEM. The 2.83 eV bandgap energy was observed in composite. The nanocomposite was evaluated for Tubantin red 8BL photodegradation. The efficiencies of pure ZnO nanoparticles after 25 min, 50 min, 75 min, 100 min, 125 min, and 150 min irradiation are 54.54 %, 58.00 %, 61.41 %, 63.84 %, 71.19 %, and 78.53 %; for pure V2O5 nanoparticles, they are 72.72 %, 76.45 %, 80.85 %, 85.42 %, 89.99 %, and 94.32 %. Similarly, the efficiencies (%) of V2O5/ZnO composite nanoparticles are 45.10 %, 53.27 %, 60.75 %, 68.24 %, 79.99 %, 91.74 %, and 99.79 %, respectively. Reusability studies (three cycles) were used to further confirm the photocatalytic efficiency, and the findings of the subsequent characterization revealed an arrangement of crystalline layers which is the cause of the high efficiency. These nanostructures also demonstrated stability across three cycles, suggesting more photocatalytic uses for them in the future.

In this study, a series of BiVO4/BiOBr composites with varying mole ratios were successfully synthesized using a hydrothermal method. The in-situ synthesis strategy facilitated the formation of a close interfacial contact between BiVO4 and BiOBr at the depletion zone, resulting in improved charge segregation, migration, reduced charge recombination, enhanced solar light absorption capacity, promoting narrow band gap, and large surface area. This study investigates the influence of different mole ratios of BiVO4 and BiOBr in a BiVO4/BiOBr nanocomposite on the photocatalytic degradation of tetracycline (TC), a pharmaceutical pollutant, and photoelectrocatalytic water splitting (PEC) under solar light irradiation. Maximum decomposition efficiency of ~90.4% (with a rate constant of 0.0159 min−1) for TC was achieved with 0.5 g/L of 3:1 BiVO4: BiOBr (31BVBI) photocatalyst within 140 min. The degraded compounds resulting from the TC abatement were analyzed using GC-MS. Furthermore, TC standards exhibited 78.2% and 87.7% removal of chemical oxygen demand (COD) and total organic carbon (TOC), respectively, while TC tablets showed 64.6% COD removal and 73.8% TOC removal. The PEC water splitting experiments demonstrated that the 31BVBI photoanode achieved the highest photocurrent density of approximately 0.2198 mA/cm2 at 1.23 V vs. RHE, resulting in the generation of approximately 1.864 mmolcm−2 s−1 of hydrogen, while remaining stable for 21,600 s. The stability of the photocatalyst was confirmed by post-degradation characterizations, which revealed intact crystalline planes, shape, and surface area. Comparisons with existing physicochemical methods used in industries indicate that the reported photocatalyst possesses strong surface catalytic properties and has the potential for application in industrial wastewater treatment and hydrogen generation, offering an advantageous alternative to costly and time-consuming processes. [ABSTRACT FROM AUTHOR]

Deprotection of pyridine N‐oxides under mild conditions with an inexpensive and environmentally friendly reducing reagent is an important chemical procedure. The use of biomass waste as the reducing reagent, water as the solvent and solar light as the energy source is one of the most promising approaches with minimal impact on the environment. Therefore, a TiO2 photocatalyst and glycerol are suitable components of this type of reaction. Stoichiometric deprotection of pyridine N‐oxide (PyNO) with a minimal amount of glycerol (PyNO:glycerol= 7 : 1) was achieved, with only CO2 being produced as the final oxidation product of glycerol. The deprotection of PyNO was thermally accelerated. Under solar light, the temperature of the reaction system increased to 40–50 °C and PyNO was also quantitatively deprotected, indicating that solar energy, i. e., UV light and thermal energy, can be effectively used. The results provide a new approach in the fields of organic chemistry and medical chemistry using biomass waste and solar light. [ABSTRACT FROM AUTHOR]

TiO2 nanotubes were synthesized by hydrothermal reaction using commercially available TiO2 powder at 150 °C for 24 h. The transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms and Fourier Transform-Infrared spectroscopy were used to characterize the nanotubes. Anatase phase was not transformed into rutile phase in the range of calcination temperature studied. Increase in calcination temperature result in enhancement of crystallinity and reduction in BET surface area. Photocatalytic removal of Reactive Red 239 (RR239) was investigated using prepared TiO2 nanotubes. Effects of pH, TiO2 nanotube dosage, initial RR239 concentration and calcination temperature were studied. 99%, 97% and 55% of removal efficiency values were attained at pH = 3, 5 and 7, respectively within 60 min or reaction time. With an increase in dosage of TiO2 nanotube in the range of 0.25–0.75 g dm−3, removal rate increased by a steeper slope. Complete removal of RR239 was observed at 20 mg dm−3 RR239 concentrations within 30 min but longer time was required for complete removal at higher concentrations. Langmuir-Hinshelwood kinetic expression was proposed based on nonlinear regression analysis. The removal efficiency of nanotubes calcined at 300 − 450 °C significantly increased but further increase in calcination temperature caused to decrease the efficiency.100% and 85% removal efficiency values were observed using actual solar light within 120 min of reaction time in July and January, respectively. Experiments conducted with scavengers showed that holes and adsorbed hydroxyl radicals were the major species involved in removal of RR239. A pathway for degradation of RR239 was suggested according to detected intermediate compounds. [ABSTRACT FROM AUTHOR]

The continuous flow reverse water gas shift (rWGS) process was efficiently catalyzed by a plasmonic Au/TiO2 nanocatalyst using sunlight as sole and sustainable energy source. The influence of the catalyst bed thickness on the CO production rate was studied, and three different catalytic regimes were identified as direct plasmon catalysis (DPC), shielded plasmon catalysis (SPC) and unused plasmon catalysis (UPC). The CO2 : H2 ratio was optimized to 4 : 1 and a maximum CO production rate of 7420 mmol ⋅ m−2 ⋅ h−1 was achieved under mild reaction conditions (p=3.5 bar, no external heating, Ee=14.0 kW ⋅ m−2), corresponding to an aparent quantum efficiency of 4.15%. The stability of the Au/TiO2 catalyst was studied for 110 h continuous operation, maintaining more than 82% of the initial CO production rate. On/off experiments mimicking discontinuous sunlight powered processing furthermore showed that the Au/TiO2 catalyst was stable for 8 consecutive runs. [ABSTRACT FROM AUTHOR]

Crude TiO 2 derived from sulfate technology was used as a precursor for the novel solar light active photocatalysts with various sulfur content (S-TiO 2). The effect of sulfur on the physicochemical properties of S-TiO 2 and efficiency of ketoprofen photodecomposition under simulated solar light was investigated. Additionally, the activity of selected photocatalysts was evaluated under visible light and UV radiation. Moreover, different scavengers were applied to explore the mechanism of ketoprofen decomposition. Furthermore, the acute toxicity tests were performed to assess a toxicological effect of the decomposition products. It was proved that the sulfur content in a range of ∼ 0.7–1.2 wt% was a key factor affecting the photoactivity under simulated solar light. The most beneficial sulfur content was ∼ 0.9 wt%. It was revealed that the solar light induced photoactivity of the examined photocatalysts derived mainly from the visible light photocatalysis mechanism, with some contribution of the UV photocatalysis mechanism. The most important oxidizing species were h+, O 2 ⦁− and ⦁OH, and among them h+ had the greatest impact under solar and visible light irradiation. However, the influence of e- cannot be disregarded. Based on the Aliivibrio fischeri bioluminescence assay a significant influence of the irradiation type on the treated solution toxicity was found. • Sulfur content was a key factor affecting the photoactivity of S-TiO 2 under simulated solar light. • Ketoprofen decomposition and mineralization efficiency increased with the increasing sulfur content up to ∼ 0.9 wt%. • Solar light activity of S-TiO 2 derives significantly from the visible light with contribution of UV photocatalysis mechanism. • The h+, O 2 ⦁− and ⦁OH were the most important oxidizing species in terms of solar light induced ketoprofen photodecomposition. • A significant influence of the radiation type on the treated solution toxicity was found based on the bioluminescence assay. [ABSTRACT FROM AUTHOR]

We developed PEDOT:PSS [poly (styrenesulfonate)-doped poly(3,4-ethylenedioxythiophene] and tungsten oxide (WO3) based hybrid thin films by facile hydrothermal method. The solution processed WO3–PEDOT:PSS hybrid thin films are fully characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV–Vis (UV), Raman, X-ray photoelectron spectra (XPS) and Brunauer–Emmett–Teller (BET) surface area analysis. XRD and SEM results suggest that WO3 has crystalline structure with monoclinic phase and spherical shaped nanoparticles (20–25 nm), which is uniformly decorated on the surface of PEDOT:PSS sheets. The value of Eg [calculated by linear extrapolating of (F(R ∞) hν)2 and hν] was evaluated to be 3.11 and 2.85 eV for pure WO3 and WO3/PEDOT:PSS, respectively. The PL intensity of WO3/PEDOT:PSS is maximum lower than the pristine WO3 and PEDOT:PSS, implying an improved interfacial contact quality at the WO3/PEDOT:PSS. Photovoltaic performance of WO3–PEDOT:PSS devices were measured under AM 1.5 G 1 sun light intensity of 100 mW/cm2. Organic solar cell devices with WO3–PEDOT:PSS layer give rise to a significant increase in JSC from 9.35 ± 0.03 to 16.2 ± 0.01 mA/cm2 respectively and in VOC from 0.28 V to 0.72 V respectively, resulting in a remarkable PCE increase from 0.592 ± 0.03 to 0.714 ± 0.02%. The WO3/PEDOT:PSS composite deliver a PCE of 7.81 ± 0.01%. The superior performance of WO3/PEDOT:PSS composite was attributed to the reduced current leakage, enhanced hole extraction characteristics, and less trap-assisted interfacial recombination via current density–voltage. [ABSTRACT FROM AUTHOR]

Good water quality is essential for life; therefore, decolorizing and detoxifying organic dye wastes (textile effluents) have gained immense environmental importance in recent years. Thus, the degradation of wastewater has become a potential need for our environment. This research aims to synthesize and investigate a ceramic-based nanomaterial catalyst for the degradation of dye solution under exposure to sunlight. A reduced graphene oxide-ZnS (rGO-ZnS) nanomaterial was qualitatively synthesized using a solvothermal method. The prepared nanomaterial was characterized using XRD, SEM, HR-TEM, EDX, XPS, and FT-IR techniques. The photocatalytic activity of the rGO-ZnS nanomaterial was checked using oxidative photocatalytic degradation of naphthol blue black dye (NBB) under direct sunlight irradiation. Here, the rGO/ZnS composite showed a significant photocatalytic performance to degraded NBB (93.7%) under direct solar light. Chemical Oxygen Demand (COD) measurements confirmed the mineralization of the dye. The influence of different radical scavengers on NBB degradation was studied. Optimum conditions for efficient degradation were determined. The antibacterial property of the prepared catalyst was studied. [ABSTRACT FROM AUTHOR]

In recent years, there has been growing interest in the application of UV/chlorine advanced oxidation processes for wastewater treatment. However, few studies have investigated this process in a strongly basic medium (pH > 10), which is a common characteristic of many industrial effluents. In addition, the use of artificial UV lamps in these processes can be costly. To address these challenges, we investigated the use of solar light (referred to as Solar-L) in the Solar-L/chlorine process for the degradation of Rhodamine B (RhB) in a strongly basic medium (pH 11). We found that separate solar light or chlorination showed no degradation after half an hour, but the Solar-L/chlorine process effectively degraded RhB, with complete removal achieved in only 30 min, using 1000 µM ClO−. The process also resulted in a significant reduction of TOC, i.e., 60% after 120 min and 80% after 240 min. Our results indicate that both •OH/O•− and reactive chlorine species (RCS) were involved in the degradation process, while O3 played no role. The process performance improved with the decreasing initial contaminant concentration and increasing temperature (up to 55 °C). The addition of a TiO2 nanocatalyst to the Solar-L/chlorine system significantly improved the RhB degradation efficiency by more than 30%. It was found that neither adsorption (on TiO2) nor Solar-L/TiO2 photolysis contributed to the dye removal by the Solar-L/chlorine/TiO2 system. Instead, the improvement associated with the Solar-L/chlorine/TiO2 system was related to the involvement of hypochlorite in the photocatalytic reaction at the catalyst surface. A detailed discussion of the effect of TiO2 was carried out based on the physicochemical properties of RhB and TiO2 catalyst with respect to the solution's pH. In conclusion, this study highlights the potential of solar light as a sustainable and efficient technology for the treatment of polluted water in strong basic media in the presence of chlorine and chlorine/TiO2 as additives. These valuable findings provide a basis for the future research and development of this promising technology for water treatment applications. [ABSTRACT FROM AUTHOR]

Metal-free photocatalysis is a sustainable and environmentally friendly method of transforming solar energy into molecules with added value. A light-harvesting photocatalyst without metal Phloxin-B (P-B) in-situ edge functionalized graphitic carbon nitride (g-C3N4) was assembled to enable the solar-light responsive photocatalytic C-H bond arylation and NADH regeneration cofactor. The photocatalytic performance was examined to estimate the C-H bond arylation and NADH regeneration efficiency by g-C3N4/P-B composite photocatalyst. The charge carrier transfer of g-C3N4 was found to be stimulated by the light harvester P-B layer, increasing the efficiency of chemical synthesis under solar light irradiation. In light of this, the g-C3N4/P-B composite photocatalyst exhibits high photocatalytic activity for the successful C-H bond arylation (98.6%) and regeneration of NADH (70.7%). This composite photocatalyst was characterized by FTIR and UV-visible spectrum along with particle size analysis, and cyclic voltammetry (CV). This effort offers a new and superficial technique to synthesize a highly efficient g-C3N4/P-B composite photocatalyst and afford a greener path for renewable energy and photocatalytic reactions. The graphical abstract represents the highly selective g-C3N4/P-B photocatalyst for the C-H bond activation of 4-bromoaryldiazonium salts with furan and regeneration of NADH under solar light irradiation. The g-C3N4/P-B photocatalyst has been effective photocatalytic property due stacking of Phloxin-B dye (P-B) on the g-C3N4 sheet. NADH regenerated and C-H bond arylated products are used as substrates in the pharma industries. [ABSTRACT FROM AUTHOR]

To overcome the limitations of ZnO as a photocatalyst, the present work reports a ternary nanocomposite (ZnO–TiO2/rGO) with a high photocatalytic activity under direct natural solar light irradiation. Reduced graphene oxide (rGO) was obtained after bio-reduction of GO using pomegranate peels. Techniques of FE-SEM, TEM, XRD, FTIR, UV–Vis DRS, Raman and PL were used for characterization purpose. The ternary nanocomposite exhibited a high photocatalytic activity towards the degradation of indigo carmine dye, resulting in an efficiency of 92% within 150 min under sunlight illumination. Accordingly, the hybridization of ZnO with TiO2 and rGO improves light absorption, promotes high separation of photogenerated charges, and solves the photocorrosion drawback of ZnO, leading to a better stability and reusability of the nanocomposite. Particularly, the prepared rGO allowed certain hydrophilicity and a better surface hydroxylation. In view of that, a comprehensive photocatalytic mechanism was proposed and discussed, referred to experiments showing the effect of holes and •OH scavengers. The findings revealed that the developed rGO hybridized with ZnO–TiO2 heterojunction can be a promising candidate for removing environmental contaminations using natural solar light. [ABSTRACT FROM AUTHOR]

Nanostructured TiO2 is one of the best materials for photocatalysis, thanks to its high surface area and surface reactivity, but its large energy bandgap (3.2 eV) hinders the use of the entire solar spectrum. Here, it is proposed that defect‐engineered nanostructured TiO2 photocatalysts are obtained by hydrogenation strategy to extend its light absorption up to the near‐infrared region. It is demonstrated that hydrogenated or colored TiO2 hollow spheres (THS) composed of hierarchically assembled nanoparticles result in much broader exploitation of the solar spectrum (up to 1200 nm) and the engineered surface enhances the photogeneration of charges for photocatalytic processes. In turn, when applied for photodegradation of a targeted drug (Ciprofloxacin) this results in 82% degradation after 6 h under simulated sunlight. Valence band analysis by photoelectron spectroscopy revealed the presence of oxygen vacancies, whose surface density increases with the hydrogenation rate. Thus, a tight correlation between degree of hydrogenation and photocatalytic activity is directly established. Further insight comes from electron paramagnetic resonance, which evidences bulk Ti3+ centers only in hydrogenated THS. The results are anticipated to disclose a new path toward highly efficient photocatalytic titania in a series of applications targeting water remediation and solar fuel production. [ABSTRACT FROM AUTHOR]

In the current research study, Nd & Mn co-doped strontium hexa-ferrite Sr 1-x Nd x Fe 12-y Mn y O 19 nanoparticles (NPs) were fabricated using facile micro-emulsion approach. The as-fabricated bare and co-doped materials were characterized for the structural X-ray diffraction (XRD), Raman and Fourier Transform of Infrared (FTIR), magnetic and photo-catalytic activities (PCA). The structural characterization confirms the synthesis of single phase M-type Sr-hexa-ferrite, along with successful doping of Nd and Mn ions at tetrahedral/octahedral site. The crystallite/grain size was observed to increase from 18 to 27 nm. The vibrating sample magnetometer (VSM) analysis revealed that the saturation magnetization (Ms), coersivity (Hc) and remanence increases on co-doping. Optical and band gap studies revealed the narrowing of energy band-gap (E g) which decreases from (2.18 eV–1.98 eV) on Nd and Mn doping which might be attributed to the new energy level generation in the co-doped materials. BET surface analysis shows well porous nature of the Nd and Mn co-doped materials with pore size 74 m2/g in comparison to 56 m2/g of un-doped material. The PCA was determined by solar-light degradation of crystal violet (CV) dye as industrial model contaminant. The results revealed that Nd and Mn co-doped Sr 1-x Nd x Fe 12-y Mn y O 19 NPs efficiently degraded CV dye (90.7%) when compared with (36.8%) of un-doped SrFe 12 O 19 NPs in the 90 min of solar-light exposure. This increase in the PCA was ascribed because of the narrow band gap and defected structure of Nd and Mn co-doped Sr 1-x Nd x Fe 12-y Mn y O 19 NPs. The stability and reusability tests revealed the excellent stability of the photo-catalyst which is only 1.10% loss observed after 5 repeated rounds which indicate its potential stability and reuse. The results of the application studies of Nd and Mn co-doped Sr 1-x Nd x Fe 12-y Mn y O 19 NPs revealed the potential uses for various electrical, as magnetic materials and for the remediation of toxic contaminants from the various industrial units and environment. [ABSTRACT FROM AUTHOR]

Although the immobilization of photocatalysts on polymeric substrates has been widely studied, it has not yet achieved industrial scale. The replacement of petrochemical polymers by biopolymers is a strategy to make this technology more sustainable; however, it is important also to dedicate attention to the synthesis of these materials. Poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a biodegradable and biocompatible polymer, but the widely used solvent for PHBV is chloroform, an extremely toxic substance to humans and the environment. Titanium dioxide (TiO2) is a highly stable and efficient photocatalyst. This study aims to examine alternative solvents for the synthesis of PHBV/ TiO2 composites and to assess the applicability of these materials in the photocatalytic degradation of contaminants in a batch reactor under simulated solar light lamp. Firstly, the solubility of PHBV in various solvents, chosen according to the Hansen solubility parameters theory, was studied, resulting in the selection of acetic acid. Then, the optimal conditions for the composites' synthesis were established. Finally, the samples were prepared using non-solvent induced phase separation (NIPS) and were evaluated for the photocatalytic degradation of methylene blue (MB) and phenol. In 90 min, 72% and 18.5% of MB and phenol were degraded under simulated solar light, respectively. Moreover, the composites were stable after 5 cycles of photocatalytic degradation of phenol, demonstrating their potential applicability in remediation photocatalysis. [ABSTRACT FROM AUTHOR]

Heterojunction photocatalysts (PC) with controllable compositions and in-built electric fields have attracted extensive research interest for their use in the remediation of environmental pollutants, owing to their supreme photocatalytic activity. Here, a simple hydrothermal route synthesizing different mole ratios of BiVO4/Sb2S3 is reported as the PC. The inclusion of Sb2S3 with BiVO4 in the BiVO4/Sb2S3 composite possesses the ability to harvest a wide spectrum of solar light, an increased surface area, and an effective charge separation of the charge carriers. The efficacy of the synthesized catalyst was gauged by the photocatalytic abatement of a recalcitrant pollutant, tetracycline. The highest decomposition efficacy of 88.7% (rate constant 0.01557 min−1) was achieved with 0.3 g/L of 1:3 BiVO4:Sb2S3 photocatalyst for the tetracycline under sunlight illumination for 120 min. The catalyst was found stable for up to five cycles with a significant retention of its efficacy. The post-degradation characterizations revealed that the photocatalyst is stable due to the intactness of its crystalline planes, morphology, and surface area. Further, gas chromatography–mass spectrometry (GC–MS) was performed to study the decomposed products formed by the abatement of tetracycline. Moreover, chemical oxygen demand/ total organic carbon (COD/TOC) removals of 80.9% and 85.4%, respectively, were observed for the tetracycline standards, while for real TC pills, it was found to be 78.3% and 82.1%, respectively. This signifies that the photocatalyst has good surface catalytic properties in comparison to the existing expensive and time-consuming physicochemical approaches used in industry. [ABSTRACT FROM AUTHOR]

This manuscript emphasizes how structural assembling can facilitate the generation of solar chemicals and the synthesis of fine chemicals under solar light, which is a challenging task via a photocatalytic pathway. Solar energy utilization for pollution prevention through the reduction of organic chemicals is one of the most challenging tasks. In this field, a metal-based photocatalyst is an optional technique but has some drawbacks, such as low efficiency, a toxic nature, poor yield of photocatalytic products, and it is expensive. A metal-free activated carbon cloth (ACC)–templated photocatalyst is an alternative path to minimize these drawbacks. Herein, we design the synthesis and development of a metal-free self-assembled eriochrome cyanine R (EC-R) based ACC photocatalyst (EC-R@ACC), which has a higher molar extinction coefficient and an appropriate optical band gap in the visible region. The EC-R@ACC photocatalyst functions in a highly effective manner for the photocatalytic reduction of 4-nitro benzyl alcohol (4-NBA) into 4-amino benzyl alcohol (4-ABA) with a yield of 96% in 12 h. The synthesized EC-R@ACC photocatalyst also regenerates reduced forms of nicotinamide adenine dinucleotide (NADH) cofactor with a yield of 76.9% in 2 h. The calculated turnover number (TON) of the EC-R@ACC photocatalyst for the reduction of 4-nitrobenzyl alcohol is 1.769 × 1019 molecules. The present research sets a new benchmark example in the area of organic transformation and artificial photocatalysis. [ABSTRACT FROM AUTHOR]

Nanocomposites (r)GO/TiO2/hyper crosslinked polymer (HCP) were prepared using ultrasonic-assisted method, and identified by (SEM), (EDS), (TEM), and (XRD) techniques. This study was performed to examine the effect of various operating parameters on photocatalytic degradation of Rhodamine B (Rh.B) over (r)GO/TiO2 embedded HCP followed by an optimization study using response surface methodology (RSM) based on Box–Behnken design (BBD). The photocatalytic activity of rGO/TiO2/polycalix[4]resorcinarene ((r)GTP) was evaluated using the cationic dye Rhodamine B as a pollutant model under solar light (intensity = 850 W/m2) between 10 and 12 am, June, Ahvaz, Iran. Response Surface Methodology was adopted for the optimization of degradation parameters viz pH, dye concentration, and nanocomposites dosage and contact time. The optimum values for the maximum Rhodamine B (Rh B) degradation of rGO/TiO2/polycalix (rGTP) and GTP were obtained, in which the degradation of rGTP was 100% and the degradation efficiency of GO/TiO2/polycalix (GTP) was 70%. ANOVA analysis results demonstrated that irradiation time and nanocomposite mass were the most significant parameters. It was found that rGO/TiO2/polycalix[4]resorcinarene (rGTP) nanocomposite displayed the best degradation yield for the dye. The results showed that the rGTP nanocomposite displayed good EIS and CV properties besides being eco-friendly and reusable. It could also show a high capacity for the elimination of the dye in the industrial wastewaters. [ABSTRACT FROM AUTHOR]

Fragrances are volatile organic compounds widely used in our daily life. Unfortunately, the high volatility required to reach human receptors reduces their persistency in the air. To contrast this effect, several strategies may be used. Among them, we present here the combination of two techniques: the microencapsulation in supramolecular gels and the use of profragrances. We report a study on the controlled lactonization of four esters derived from o-coumaric acid. The ester lactonization spontaneously occurs after exposure to solar light, releasing coumarin and the corresponding alcohol. To determine the rate of fragrance release, we compared the reaction in solution and in a supramolecular gel and we demonstrated that the lactonization reaction always occurs slower in the gel. We also studied the more suitable gel for this aim, by comparing the properties of two supramolecular gels obtained with the gelator Boc-L-DOPA(Bn)2-OH in a 1:1 ethanol/water mixture in different gelator concentration (0.2% and 1% w/v). The gel prepared with 1% w/v gelator concentration is stronger and less transparent than the other and was used for the profragrances encapsulation. In any case, we obtained a significative reduction of lactonization reaction in gel, compared with the same reaction in solution. [ABSTRACT FROM AUTHOR]

To address recent energy and environmental issues, such as global warming and resource depletion, significant interest has been shown in carbon dioxide (CO2) fixation based on photoelectrochemical processes under solar light irradiation. The present paper describes the applicability of gold nanoparticles-decorated silicon nanowire arrays (Au/SiNW) as photoelectrodes to promote CO2 reduction. The decoration with Au nanoparticles of SiNW was performed by an electroless plating utilizing surface hydrogen-terminated silicon groups, generated during the nanowire formation process. Au/SiNW exhibits efficient photoelectrochemical performance for CO2 reduction to produce CO selectively in an aqueous medium under simulated solar light irradiation owing to its vertically aligned nanowire structure and Au nanoparticles as cocatalysts. The former provides high specific surface area and light trapping effect, and the latter induces selective interaction with CO2. Moreover, a unique two-steps method for Au decoration that consists of photo-assisted deposition of copper nanoparticles and the following electroless plating to replace Cu atoms to Au ones achieves more uniform decoration of SiNW with highly dispersed core–shell structured Cu@Au nanoparticles. The resulting photoelectrode, termed Cu@Au/SiNW, shows improved selectivity toward CO production and gives a good Faradic efficiency of 72% in an aqueous medium. [ABSTRACT FROM AUTHOR]

This study presents a relatively low-cost method for modifying TiO2-based materials for photocatalytic bacterial inactivation. The photocatalytic inactivation of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus epidermidis) bacteria using modified sulphated TiO2 was studied. The modification focused on the reduction of TiO2 by ammonia agents and hydrogen at 400–450 °C. The results showed a high impact of sulphate species on the inactivation of E. coli. The presence of these species generated acid sites on TiO2, which shifted the pH of the reacted titania slurry solution to lower values, around 4.6. At such a low pH, TiO2 was positively charged. The ammonia solution caused the removal of sulphate species from TiO2. On the other hand, hydrogen and ammonia molecules accelerated the removal of sulphur species from TiO2, as did heating it to 450 °C. Total inactivation of E. coli was obtained within 30 min of simulated solar light irradiation on TiO2 heat-treated at 400 °C in an atmosphere of Ar or NH3. The S. epidermidis strain was more resistant to photocatalytic oxidation. The contact of these bacteria with the active titania surface is important, but a higher oxidation force is necessary to destroy their cell membrane walls because of their thicker cell wall than E. coli. Therefore, the ability of a photocatalyst to produce ROS (reactive oxidative species) will determine its ability to inactivate S. epidermidis. An additional advantage of the studies presented is the inactivation of bacteria after a relatively short irradiation time (30 min), which does not often happen with photocatalysts not modified with noble metals. The modification methods presented represent a robust and inexpensive alternative to photocatalytic inactivation of bacteria.

Nowadays, the presence of humic acid (HA) in water sources is highly regarded due to the production of extremely harmful byproducts such as trihalomethanes. In this study, the effectiveness of an Ag3PO4/TiO2 catalyst produced by in situ precipitation as a heterogeneous catalyst for the degradation of humic acid in the existence of visible and solar light was evaluated. The Ag3PO4/TiO2 catalyst's structure was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), after which the catalyst dosage, HA concentration, and pH parameters were adjusted. After a 20-min reaction, the highest HA degradation of 88.2% and 85.9% in presence of solar light and visible light were attained at the ideal operating conditions of 0.2 g/L catalyst, 5 mg/L HA, and pH 3, respectively. It was discovered that, based on kinetic models, the degradation of HA matched both Langmuir-Hinshelwood and pseudo-first-order kinetics at concentrations of 5 to 30 mg/L (R2 > 0.8). The Langmuir-Hinshelwood model had surface reaction rate constants (Kc) of 0.729 mg/L.min and adsorption equilibrium constants (KL-H) of 0.036 L/mg. Eventually, a real-water investigation into the process' effectiveness revealed that, under ideal circumstances, the catalyst had a reasonable HA removal efficiency of 56%.

A novel BiOY (Y = Br/Cl) heterojunction nanocatalyst was synthesised chemically and compared with three different BiOX (X = Br/Cl/I) nanocatalysts as well as a physical admixture of BiOBr/BiOCl catalysts in the photocatalytic degradation of malachite green dye wastewater under solar irradiation in both suspended and immobilised forms using polysulfone as the substrate. Catalyst characterisation was done by a particle size analyser, SEM/EDX, XRD, FTIR, and DRS. In the suspended form, BiOBr showed 100% degradation within 70 min, BiOCl showed 99.3%, and BiOI showed 11.2% degradation within 120 min, and it is found to follow pseudo-first-order kinetics. In the immobilised form, BiOBr showed 89.1%, and BiOCl showed 83.4% degradation within 180 min under sunlight. The degradation measured by TOC reduction for these catalysts in suspended form was 67.4%, 57%, and 40%, affirming BiOBr as the best among these catalysts. The performance of the immobilised chemically synthesised BiOY and physical admixture catalysts were 88% and 14%, respectively. The enhanced activity in the chemically synthesised immobilised BiOBr/Cl catalyst can be attributed to the effective charge separation at the heterojunction interface. These photocatalysts are very active under solar light and hence suitable for the efficient degradation of other recalcitrant organic contaminants. [ABSTRACT FROM AUTHOR]

Ternary PANI@Bi2O3-BiOCl nanocomposites were successfully synthesized during the oxidative polymerization of aniline monomer in the presence of Bi2O3. PANI@Bi2O3-BiOCl nanocomposites were characterized by several analytical techniques, including X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), N2 physisorption, UV–Vis Diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The effective PANI-semiconductor interaction promotes the fast separation and transfer of photogenerated electrons and holes, enhancing the photocatalytic efficiency of the materials towards methylene blue (MB) degradation under solar light irradiation. The best results were obtained by 0.5%PANI@Bi2O3-BiOCl, leading to 80% MB degradation in 2 h, four times higher than pristine Bi2O3-BiOCl. Moreover, 0.5%PANI@Bi2O3-BiOCl maintained stable photocatalytic performances for four cycles without significant activity loss. Various scavengers (isopropyl alcohol, formic acid, and benzoquinone) were used to identify the active species by trapping holes and radicals generated during the photocatalytic degradation process. Finally, a probable photocatalytic mechanism of PANI@Bi2O3-BiOCl photocatalyst was suggested. [ABSTRACT FROM AUTHOR]

In this study, a series of highly crystalline π-conjugated polyimide photocatalysts with porous nano hollow shell (HSPI) was prepared for the first time by the hard template method by adjusting the addition ratio of the template precursor. SiO2 nanospheres not only serve as template agents but also as dispersants to make precursors of SPI more uniform, and the degree of polymerization will be better, resulting in significantly enhanced crystallinity of HSPI relative to bulk SPI (BSPI). More strikingly, it is found that HSPI has a larger specific surface area, stronger visible light absorption, and higher separation efficiency of photogenerated electron and hole pairs compared with BSPI by various spectral means characterization analysis. These favorable factors significantly enhanced the photocatalytic degradation of methyl orange (MO) by HSPI. This work provides a promising approach for the preparation of cheap, efficient, environmentally friendly, and sustainable photocatalysts. [ABSTRACT FROM AUTHOR]

• Amoxicillin removal was investigated using the solar light–photocatalytic process. • FeNi 3 /SiO 2 /TiO 2 nanocomposite was prepared and applied as the photocatalyst. • 96% amoxicillin removal was achieved after 30 min of degradation reactions. • FeNi 3 /SiO 2 /TiO 2 has high stability over four photocatalytic cycles of amoxicillin. This research aims to develop a novel photocatalyst with excellent photocatalytic performance and investigate its potential to remove amoxicillin (AMOX) from an aqueous solution. First, FeNi 3 /SiO 2 /TiO 2 was characterized using X-ray diffraction, scanning electron microscope, Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. Then, the FeNi 3 /SiO 2 /TiO 2 nanocomposite was tested for its ability to degrade AMOX in a batch solar-photocatalysis reactor. The effects of parameters such as pH, contact time, initial concentration, and nanocomposite dose were investigated during the experiments. The results demonstrated the performance by degrading 10 mg/L of AMOX solution to 96 % after 30 min in the dark and 90 min of solar irradiation and using 50 mg/L of nanocomposite at pH =5. Furthermore, the kinetic of the degradation rate of AMOX followed the pseudo-first-order equation with R2 > 0.987, and this reaction's constant rate of degradation was obtained as 0.03 1/min. The used catalyst showed high recycling efficiency and stability over four photocatalytic cycles. This study showed that FeNi 3 /SiO 2 /TiO 2 magnetic nanocomposite in a solar–photocatalytic reactor under optimum operating conditions has a reasonable efficiency in the degradation of AMOX. [ABSTRACT FROM AUTHOR]

Context and results: In this study, the heterojunction Cu2O/TiO2 is used for the degradation of a cationic dye, Rhodamine B, under solar light irradiation over a wide pH range. The physical and optical properties of both semiconductors Cu2O and TiO2 are correlated with the photo-electrochemical characterization to establish the energy diagram of the heterojunction Cu2O/TiO2. X-ray diffraction, UV–visible, SEM, EDX, and BET analyses are conducted for both photocatalysts. The band gap (Eg) of 3.26 eV is obtained for TiO2 with an indirect optical transition. In the case of Cu2O, the transition is directly allowed at 2.05 eV. According to the BET analysis, the specific surface area of TiO2 particles is higher (82.65 m2 g−1) than that of Cu2O (29.81 m2 g−1). The flat band potentials, determined from the Mott-Schottky plots, are 0.3 and − 0.32 VSCE for TiO2 and Cu2O, respectively. The photocatalytic activity is directly proportional to the mass ratio, and the best result is obtained for the mass ratio 1:1 of Cu2O/TiO2. Computational and theoretical techniques: Furthermore, a theoretical study is conducted by using density functional theory to optimize the structure, reactivity sites of the RhB molecule, and physical parameters like the energy of the frontier molecular orbitals and electronegativity and to predict the proposed mechanism of RhB degradation as well as its intermediates. Also, molecular dynamics simulation is used to determine the adsorption behavior of RhB on TiO2 (101) and Cu2O (111) surfaces. The ecotoxicity evaluation showed that degradation products have significantly lower acute toxicity than RhB. [ABSTRACT FROM AUTHOR]

Existence of pharmaceutical residues in water has endangered environmental pollution worldwide, which makes it ineludible to develop prospective bifunctional materials which not only possess excellent fluorescence behaviour to monitor pharmaceuticals but also exhibit simultaneous photocatalytic removal efficiency. Strengthened by functionalized metal organic framework (MOF) materials, we present here an amine functionalized zirconium-based MOF NH2-UiO-66 which has been successfully synthesized using solvothermal approach. The as prepared MOF was subjected to numerous structural, morphological and compositional characterizations. Interestingly, featured by the excellent fluorescent intensity of MOF modulated by LMCT effect, NH2-UiO-66 was screened to detect pharmaceutical compounds with KTC and TC in aqueous solution. The prepared functionalized MOF showcased excellent sensing platform with magnificent response range (0‒3 µM), lower limit of detection (160 nM; KTC and 140 nM; TC), excellent selectivity and influential anti-interference capability. More importantly, the practical utility of the proposed sensor was further explored for the determination of pharmaceutical drugs in real water samples with suitable recoveries. Simultaneously, the synthesized MOF also exhibited high photocatalytic efficiency towards the removal of KTC and TC under solar light irradiation. The degradation efficiency for KTC and TC was found to be 68.3% and 71.8% within 60 and 280 min of solar light, respectively. Moreover, excellent recyclability was demonstrated by the current synthesized system over five cycles. Overall, this study presents a feasible route for the utilization of functionalized MOFs as potential dual functional materials towards the simultaneous detection and degradation of specific pharmaceuticals from aqueous medium. [ABSTRACT FROM AUTHOR]

The use of semiconductors for bacterial photoinactivation is a promising approach that has attracted great interest in wastewater remediation. The photoinactivator Cu-TTC/ZTO/TO was synthesized by the solvothermal method from the coordination complex Cu(C3H3N3S3)3 (Cu-TTC) and the hybrid semiconductor ZnTiO3/TiO2 (ZTO/TO). In this study, the effect of photocatalyst composition/concentration as well as radiation intensity on the photoinactivation of the gram-negative bacteria Escherichia coli and the gram-positive bacteria Staphylococcus aureus in aqueous solutions was investigated. The results revealed that 25 mg/mL of photoinactivator, in a Cu-TTC:ZTO/TO molar ratio of 1:2 (w/w%) presents a higher rate of bacterial photoinactivation under simulated solar light (λ = 300–800 nm) in comparison to the individual components. The evidence of this study suggests that the presence of the Cu(C3H3N3S3)3 coordination complex in the ZnTiO3/TiO2 hybrid semiconductor would contribute to the generation of reactive oxygen species (ROS) that are essential to initiate the bacterial photoinactivation process. Finally, the results obtained allow us to predict that the Cu-TTC/ZTO/TO photocatalyst could be used for effective bacterial inactivation of E. coli and S. aureus in aqueous systems under simulated solar light. [ABSTRACT FROM AUTHOR]

The innovation of a highly efficient and inexpensive graphene oxide-based photocatalyst is a challenging task for selective solar chemical regeneration/coenzyme such as nicotinamide adenine dinucleotide (NADH). Herein, we have designed lemon-juice derived highly efficient S-GQD/GO composite as a photocatalyst for regeneration of NADH under solar light. The rational design of a highly efficient photocatalytic system through the orientation of S-GQD on graphene oxide as solar light harvesting photocatalyst is explored for the first time for NADH regeneration. This highly solar light active S-GQD/GO composite photocatalyst upon integration with the NAD+ is used for highly regioselective regeneration of coenzyme (76.36%). The present work provides the benchmark instances of graphene oxide-based material as a photocatalyst for selective regeneration of NADH under solar light and opens a new door for green synthesis. [ABSTRACT FROM AUTHOR]

In this study, a novel direct Z-scheme SnS2 quantum dots/sulfur-doped polyimide (SQDs/SPI) photocatalyst was firstly fabricated by an in situ crystallization growth of SnS2 quantum dots on sulfur-doped polyimide through a facile hydrothermal method. The photocatalytic hydrogen production activity of 5SQDs/SPI samples reached 3526 μmoL g−1 in the coexistence of triethanolamine and methanol used as hole sacrificial agents, which is about 13 times higher than that of SPI under the same conditions and 42 times higher than that of SPI only as a hole sacrificial agent. The improvement can be related to the direct Z-scheme charge transfer in the tight interface between SQDs and SPI, which promoted rapid separation and significantly prolonged the lifetime of photoexcited carriers. The Z-scheme charge transfer mechanism was proposed. This discovery comes up with a new strategy for the development of an efficient, environmentally friendly, and sustainable sulfide quantum dots/polymer non-noble metal photocatalyst. [ABSTRACT FROM AUTHOR]

In this work, Ag2CO3 was prepared via a solution-based method and was further characterized by XRD, Raman spectroscopy, SEM/EDS analysis, and UV-VIS spectroscopy. SEM results revealed the formation of micro-sized particles with a rectangular shape. The photocatalytic activity of the catalyst was evaluated in the degradation of 4-tert-butylphenol (4-t-BP) under simulated solar light irradiation. The effects of 4-t-BP initial concentration (2.5–10 ppm), catalyst dosage (100–300 mg/L), different types of lamp sources, and water matrix were investigated. Complete 4-t-BP (5 ppm) degradation was achieved after 60 min by Ag2CO3 (200 mg/L). The effect of anions such as CO32−, HCO3−, NO3−, and Cl- in the concentration range of 100–300 mg/L was also studied. CO32− promoted the photocatalytic degradation process, while HCO3− and NO3− exhibited an inhibition effect, which was marked with increasing HCO3− and NO3− concentrations. The presence of Cl− at the concentration of 100 mg/L increased 4-t-BP degradation, but higher concentrations inhibited the photocatalytic reaction. Cyclic experiments showed that the catalyst practically retained its catalytic activity toward 4-t-BP degradation after three successive experimental runs. [ABSTRACT FROM AUTHOR]

Azo dyes such as Reactive Red 120 raise great concerns about their increased harmfulness. Photocatalytic degradation is considered to be one of the most efficient techniques for Reactive Red 120 degradation. Herein, a highly solar active graphitic carbon nitride–assisted bismuth phosphate nanocomposite (BiPO4@g-C3N4) was synthesized by the thermal decomposition of melamine followed by the co-precipitation method. Various analytical techniques were utilized to characterize the prepared BiPO4, g-C3N4, and BiPO4@g-C3N4 nanocomposites. Scanning electron microscopy (SEM) shows the nanorods and particle morphology of the bare BiPO4 and g-C3N4 respectively. Furthermore, the optical band gap energies of the BiPO4, g-C3N4, and BiPO4@g-C3N4 nanocomposite have been calculated to be 4.20, 2.66, and 2.68 eV respectively. Under sunlight, the BiPO4@g-C3N4 nanocomposite showed higher photocatalytic activity towards the degradation of RR120. The BiPO4@g-C3N4 nanocomposite efficiently degrades the RR120 under sunlight with a higher first-order reaction rate constant of 0.0145 min−1. This is seven times higher than that of bare BiPO4 (0.0019 min−1) nanorods and four times greater than g-C3N4 (0.0036 min−1). The photocatalytic efficiency was found to be maximum at pH 4 and decreased as the pH of the solution increased. Even after five recycle runs, the catalyst performance of the RR120 dye has decreased by less than 5%, indicating the high stability of the BiPO4@g-C3N4 nanocomposite. Furthermore, the radical trapping experiment demonstrates that the active species in the dye degradation process are holes and hydroxide radicals. The photocatalytic mechanism was proposed for the BiPO4@g-C3N4 nanocomposite and further validated by the electrochemical impedance spectroscopy analysis. [ABSTRACT FROM AUTHOR]

The present work aimed at the development of Pt-TiO2/SiO2 materials applied to the degradation of a pharmaceutical pollutant in a fixed-bed microreactor in continuous mode. First, a wide investigation of the optimal platinum content in TiO2/SiO2 was carried out based on extensive characterization through XRD, DRS, SEM, TEM, and XPS techniques. For the content range studied, no significant changes were observed in the crystallinity of the material, with peaks related to the anatase phase and PtO2 in the diffractograms. SEM images combined with EDS spectra indicated the presence of platinum and a large heterogeneity in the particles. MET analyses showed PtO2 nanoparticles in close contact with TiO2, allowing the formation of a type II heterojunction. XPS showed platinum in the 0 and +4 oxidation states, suggesting that platinum metal and PtO2 are both present. Regarding the degradation experiments, the optimal catalyst achieved 81% degradation of acetaminophen for a residence time of 1 h, while the catalyst without platinum reached only 27% degradation. The catalyst activity dropped from 81 to 57% in 2 h and remained stable for six reuse cycles. Increasing the inlet flow rate and concentration reduced the pollutant degradation although there was an increase in the reaction rate. Finally, a photocatalytic mechanism was proposed in which a type II heterojunction was developed, with generation of hydroxyl radicals by the positive holes in the VB of TiO2 as well as superoxide radicals by the electrons in the CB of PtO2. [ABSTRACT FROM AUTHOR]

Using the hetero-junction Fe2O3/WO3, a significant rate of photocatalytic activity was obtained for the degradation of Ponceau S Red dye (PSR) under solar irradiation. The mass ratio of Fe2O3 / WO3 was studied. Similarly, the experimental conditions leading to the total degradation of Ponceau S Red dye were optimized. The physical and optical properties of both semiconductors Fe2O3 and WO3 were correlated with the photo-electrochemical characterization to establish the energy diagram of the hetero-junction Fe2O3/WO3/electrolyte. The XRD, UV–visible and BET analyses were performed for both prepared compounds. Fe2O3 and WO3 have the band gap values of 2.18 and 2.66 eV, respectively and their optical transition is directly allowed. The flat band potentials, determined from the capacitance−2 – potential (C−2–E) plots are found to be − 0.16 and 0.47 VSCE, respectively. The absorption of visible light produces a transfer of electrons from the conduction band of Fe2O3 (− 0.61 VSCE) toward low trapping of WO3–CB energy sites (0.04 VSCE), which promotes the separation of charge carriers and therefore accelerates the PSR degradation. Under solar light illumination and the following conditions: pH ∼ 8, T ∼ 25 °C, and a catalyst dose of 1 mg/mL, total degradation of 10 mg/L of PSR is obtained. The chemical oxygen demand test confirms that most of Ponceau S Red dye was completely mineralized by photocatalytic process. [ABSTRACT FROM AUTHOR]

In the present study Co3O4 and Sr‐Co3O4 nanoparticles were prepared by sol‐gel and co‐precipitation methods and tested as photo‐catalysts for the degradation of methylene blue (MB, model molecule of the thiazine dyes class) and malachite green (MG, model molecule of the triphenylmethane category)under solar light irradiation. To study the photocatalytic activity, Co3O4 was doped by three different weight percentages of strontium (5%, 10%, and 15%). Among these, 10 wt% Sr‐Co3O4, named as (10)Sr‐Co3O4, showed maximum photodegradation efficiency toward both MB and MG. Their structural and morphological characteristics, chemical composition, surface area, and optical properties were investigated by FT‐IR spectroscopy, X‐ray diffraction (XRD), Field Emission Scanning Electron Microscopy – Energy Dispersive Spectroscopy (FE‐SEM‐EDX), UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) analysis. The XRD investigations of Co3O4 and (10)Sr‐Co3O4 catalysts indicated retention of structure. The effect of initial pH, initial concentration of the dyes and photocatalysts dose was properly investigated. The results demonstrated the enhanced photocatalytic activity of (10)Sr‐Co3O4 compared to that of pristine Co3O4 due to Sr doping that improves electron‐hole (e–/h+) pairs separation mediated by charge migration on the Sr‐Co3O4 structure. The as‐prepared photocatalyst exhibited a remarkable photocatalytic efficiency towards both the dyes. (10)Sr‐Co3O4 and Co3O4 degraded 96% and 88% of MB at pH = 11, and 92% and 85% of MG at pH = 9, respectively in 90 min. Moreover, it was demonstrated that the photodegradation of MB and MG by Sr‐Co3O4 and Co3O4 followed a pseudo‐first‐order kinetics. Both the photocatalysts showed good stability during recycling maintaining high performances after five cycles. Finally, the active species were identified using various scavengers by trapping holes and radicals generated during the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

Water contamination is now a big issue all around the world. So the discovery and progress of efficient and long‐lasting visible‐light‐active photocatalysts are the most difficult current research fields. Using a simple sonication process followed by thermal polymerization, a p‐n heterojunction structure of g‐C3N4/Bi4Ti3O12 (g‐C3N4/BTO) photocatalyst was prepared. The photocatalyst's morphologies, structures, and optical characteristics were meticulously investigated using XRD, FT‐IR, SEM, TEM, EDAX, and UV–DRS. The increased photodegradation efficiency might be attributed to the p‐n heterojunction of g‐C3N4/BTO, which has a high oxidative capacity, a smaller bandgap, greater visible‐light absorption capacity, and a decreased recombination rate of photo‐excited electron‐hole pairs. At pH 3, maximal photodegradation of 98% for RhB and 93% for MG dye was reported in 20 and 30 min, respectively. Furthermore, rhodamine B (RhB) and malachite green (MG) photocatalytic degradation proceeded at pseudo‐first‐order rates, with K values of 0.193 min–1 and 0.089 min–1, approximately. Based on the experimental results, a plausible mechanism for the improved photocatalytic activity was proposed. Meanwhile, the recycling experiment validated the g‐C3N4/BTO's high stability and endurance. The matching band locations and successful charge separation might be the mechanism underlying the improvements of photodegradation. Apart from that, based on the scavenger test, photogenerated superoxide radical (O2−·${O}_2^{ - \cdot }$ and holes (h+) might be the major radicals in the degradation process. This research is likely to pave the way for the development of innovative visible‐light‐driven materials via nanostructure design. [ABSTRACT FROM AUTHOR]

Heterogeneous semiconductor photocatalysis has attracted researcher's attention in wastewater treatment owing to the improved surface area, optical properties, and charge transfer rate for boosted degradation of organic pollutants. Thus, the g-C 3 N 4 /Ag/TiO 2 was prepared following a hydrothermal route for the degradation of azo dye tartrazine (TA) used as a food colourant under solar light. Before application, the composite and pristine materials were interrogated for physicochemical and structural properties using SEM, TEM, EDS, XPS, XRD, UV–vis DRS, PL, BET, Raman, and FTIR spectroscopy. The PL and electrochemical analysis revealed that the CNAT composite had a high charge transfer rate that was coupled with low charge carrier complexation. The degradation efficiency of 91 % was realized in 180 min and the rate of pseudo-first-order kinetics of 0.01143 min−1 was obtained. The CNAT catalyst also displayed high removal efficiency towards a cocktail of naproxen (NPX) and TA. The improved removal efficiencies stem from increased visible usage, reduced charge carrier compounding, and formation of Z-scheme heterojunction with high redox capabilities. The total organic carbon removal reached 95 % while CNAT showed high convincing stability even after four cycles. Given the above results, the hydrothermally prepared composite catalyst can be extended to other organic pollutants such as pharmaceuticals, pesticides, and reduction of inorganics. • CNAT with the mixture of (TA and NPX) had 98 % TA and 40 % NPX degradation efficiency after synthesized by hydrothermal method. • Anatase CNAT composite was stable after four cycles. • Synthesized composite had high degradation efficiency. • Mineralization of TA and NPX, and degradation pathway was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Z-scheme FeS/MgIn 2 S 4 heterojunction was obtained for photocatalysis-PMS removal of TCH. • FeS/MgIn 2 S 4 hybrid exhibited the better activity than FeS and MgIn 2 S 4. • Z-scheme interface between FeS and MgIn 2 S 4 facilitated for charge transfer and migration. Photocatalysis induced peroxymonosulfate (PMS) oxidation has been confirmed as a potential route to eliminate antibiotics of wastewater. To boost the solar-light driven photocatalysis-PMS activity of MgIn 2 S 4 for tetracycline hydrochloride (TCH) degradation, Z-scheme FeS/MgIn 2 S 4 heterojunction was fabricated via the solvothermal approach. The Z-scheme structure between FeS and MgIn 2 S 4 was likely to separate and migrate photo-generated e−/h+ pairs and to suppress the recombination of charge carriers. In addition, S defects and Fe2+/Fe3+ couples were likely to form active radicals, including SO 4 −, OH, and O 2 −. For comparison to FeS and MgIn 2 S 4 , FeS/MgIn 2 S 4 hybrids exhibited the better photocatalysis-PMS activity for TCH removal. The removal efficiency of TCH over 3-FeS/MgIn 2 S 4 with a nominal Fe/Mg molar ratio was 98.88 % within 140 min, and declined to 90.97 % after five cycle times. The deactivation of 3-FeS/MgIn 2 S 4 was attributed to the valence states variation of surface components under long-term irradiation. [ABSTRACT FROM AUTHOR]

• Cu 2 O with 1-shell, 2-shell and 3-shell is successfully synthesized. • The activity of Cu 2 O for PAA activation improves as the shell increases. • The increased shell improves the photothermal conversion efficiency of Cu 2 O. • High photothermal conversion promotes in-situ activation of PAA. Advanced oxidation processes based on light-mediated peracetic acid (PAA) activation are novel degradation systems for wastewater purification. In this work, different shells of Cu 2 O are controllably synthesized and used to activate PAA under simulative solar light. Interestingly, the k obs in the system without temperature control is 2.47 times that in the temperature-controlled system, implying the important role of the photothermal conversion effect in PAA activation. Reactive oxygen species identification demonstrates that photothermal promotes the decomposition of PAA into radical OH with higher redox potential instead of R–O, which together with non-radical 1O 2 achieves a high mineralization rate (72.49%). The core–shell structure enhances light absorption and photogenerated charge separation of Cu 2 O, thereby improving photothermal conversion efficiency. Meantime, the in-situ photothermal conversion effect expedites the diffusion of ROS and the cycle of active Cu(Ⅱ)/Cu(Ⅰ) ultimately achieves the high-efficiency and long-lasting PAA activation. This work provides novel strategies for solar energy utilization and PAA activation processes in wastewater purification. [ABSTRACT FROM AUTHOR]

• Easy to make graphene-based visible light active photocatalyst (N en G-RhB) via condensation. • The N en G-RhB photocatalyst appears to be a noteworthy development, demonstrating its efficiency in the degradation of industrial orange g in the presence of solar light as well as the oxidative cyclization of aromatic thioamide. • Its potential for useful applications in solar-driven catalysis and environmental remediation is shown by the remarkable degradation efficiency of 97.29 % for the industrial dye and a high conversion rate of 92.5 % for the cyclization. This may open the door to more eco-friendly and productive procedures across a range of sectors. Functionalized photocatalysts have shown to be an effective method for oxidative cyclization processes and the degradation of organic poisons like chemicals and dyes. In this study, we report the facile, environmentally friendly, room-temperature (RT) synthesis and development of a graphene-based visible light active photocatalyst (NenG-RhB) which is thermodynamically converted to nitrogen-enriched graphene (NenG) covalently bonded to a light-harvesting RhB molecule [9-(2-Carboxyphenyl)-6-(diethylamino)-N, N‑diethyl-3H-xanthen-3-iminium chloride)]. The NenG-RhB photocatalyst is extremely effective, resulting in good oxidative cyclization of aromatic thioamide (92.5 %) and degradation efficiency of industrial orange G (97.29 %) under solar light. The current research focuses on the invention and implementation of a nitrogen-enrich graphene-based photocatalyst for direct solar medicinal chemical synthesis and industrial dye degradation in wastewater using solar light. [ABSTRACT FROM AUTHOR]

The rise of nanoplastics (NPs) as a water pollutant poses threats to aquatic ecosystems and human health. This study presents an approach that combines solar and water-driven energy sources with advanced materials to degrade NPs. For this purpose, a SnO 2 /g-C 3 N 4 /PVDF-HFP piezo-photocatalyst has been developed. The SnO 2 /g-C 3 N 4 photocatalyst with Z-Scheme charge transfer demonstrates high activity under simulated solar light. Simultaneously, ultrasound waves, employed to mimic water motion, serve to activate the piezoelectric properties of g-C 3 N 4 , thereby enhancing charge separation. Moreover, the immobilization of SnO 2 /g-C 3 N 4 onto piezoelectric poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber mats augments its piezocatalytic efficiency and prevents dispersion in the reaction media. During the piezo-photocatalytic process, generated reactive species attack polystyrene (PS) NPs and introduce oxygen-based functional groups. This leads to surface corrosion, fragmentation, and 46 % mineralization in just 15 h under mild conditions, outperforming existing literature. Overall, this research emphasizes the importance of harnessing renewable energy sources for NP remediation. [Display omitted] • PVDF-HFP serves as a piezoelectric substrate for Z-scheme SnO 2 /g-C 3 N 4 photocatalyst. • The piezo-photocatalytic process harness solar and water energy for NPs degradation. • PS NPs present surface erosion and fragmentation after 15 h of treatment. • The degraded NPs contain new functional groups. • 15 h of irradiation in mild conditions results in 46 % NPs mineralization. [ABSTRACT FROM AUTHOR]

LaFeO 3 /MgFe 2 O 4 heterojunctions were prepared via the sol-gel route to enhance solar-light induced photo-persulfate degradation of tetracycline hydrochloride (TCH). LaFeO 3 /MgFe 2 O 4 exhibited the better removal efficiency of TCH in comparison to LaFeO 3 and MgFe 2 O 4. The photo-persulfate activity of LaFeO 3 /MgFe 2 O 4 was intensively affected by LaFeO 3 content, pH, and inorganic salts. Under the optimal conditions, 2-LaFeO 3 /MgFe 2 O 4 with a nominal LaFeO 3 content of 10 wt % presented the removal efficiency of 97.01 %, while declined to 85.40 % after ninth-cycle test. The lattice defects formed in LaFeO 3 and MgFe 2 O 4 acted as the active sites for TCH adsorption and photon capture. The oxygen-defected tight interface between LaFeO 3 and MgFe 2 O 4 was favorable for the separation and migration of photo-induce e-/h+ pairs, boosting solar-light response for photo-persulfate activity of LaFeO 3 /MgFe 2 O 4. However, the long-term photo-corrosion inevitably induced to the change in valance states of surface compositions, weakening the photo-persulfate performance in TCH elimination. [Display omitted] • LaFeO 3 /MgFe 2 O 4 hybrids were prepared via the sol-gel approach. • LaFeO 3 /MgFe 2 O 4 had the strong solar-light photo-persulfate activity for TCH degradation. • The tight interface favored the transfer and migration of photo-induced e-/h+ pairs. • Photo-induced radicals and Fe2+/Fe3+ couples promoted the persulfate oxidation. [ABSTRACT FROM AUTHOR]