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The native forest of northwestern Argentina, as part of the Chaco region, is a rich and unexploited source of phytochemical compounds for medicinal/cosmetic applications. In the present study, fruit, leaf, branch, and bark organs of the native trees Sarcomphalus mistol (Mistol, M) and Schinopsis lorentzii (Quebracho Colorado santiagueño, QC) were harvested, and aqueous plant extracts (PE) were prepared. The spectroscopic (UV–Vis absorbance, diffuse reflectance, ATR-FTIR) and antioxidant (TEAC, Folin–Ciocalteu) properties of PE were characterized and used as TiO2 coating material to obtain a series of TiO2@PE nanocomposites. These materials showed almost null photocatalytic activity compared to aqueous suspensions of bare TiO2, displaying yellowish to brownish coloration and high long-term stability in both freshwater and seawater model solutions. The loss of photocatalytic activity in TiO2@PE was associated with the combination of the internal filter effect and the antioxidant/radical capacity exerted by the phytochemicals of the PE coating, with higher broadband photoprotection for the nanocomposites prepared with QC extracts. Thus, this study shows the potential capacity of the forest resources of the Chaco region of Argentina for the development of new cosmetic and/or sun protection formulations. [ABSTRACT FROM AUTHOR]

Photocatalytic air purification is widely regarded as a promising technology, but it calls for more efficient photocatalytic materials and systems. Here we report a strategy to introduce an in-situ water (self-wetting) layer on WO3 by coating hygroscopic periodic acid (PA) to dramatically enhance the photocatalytic removal of hydrophilic volatile organic compounds (VOCs) in air. In ambient air, water vapor is condensed on WO3 to make a unique tri-phasic (air/water/WO3) system. The in-situ formed water layer selectively concentrates hydrophilic VOCs. PA plays the multiple roles as a water-layer inducer, a surface-complexing ligand enhancing visible light absorption, and a strong electron acceptor. Under visible light, the photogenerated electrons are rapidly scavenged by periodate to produce more •OH. PA/WO3 exhibits excellent photocatalytic activity for acetaldehyde degradation with an apparent quantum efficiency of 64.3% at 460 nm, which is the highest value ever reported. Other hydrophilic VOCs like formaldehyde that are readily dissolved into the in-situ water layer on WO3 are also rapidly degraded, whereas hydrophobic VOCs remain intact during photocatalysis due to the "water barrier effect". PA/WO3 successfully demonstrated an excellent capacity for degrading hydrophilic VOCs selectively in wide-range concentrations (0.5−700 ppmv). Photocatalytic air purification is promising but it calls for more efficient photocatalytic materials and systems. Here, the authors report a strategy to introduce an in-situ water layer on WO3 by coating hygroscopic periodic acid that effectively remove hydrophilic volatile organic compounds. [ABSTRACT FROM AUTHOR]

In this research, a novel LaCdSe-GO-TiO2 (LCS-G-T) has been synthesized by utilizing a high powersonic method under controlled condition. From the structural morphology, it is apparent that the composite is a good example of size control and low-cost synthesis with an ultrasound and scavenger effect. The synthesized LaCdSe-GO-TiO2 (LCS-G-T) composite has given a good efficiency for photocatalytic water splitting for hydrogen evolution. The implementation of high ultrasonic power has increased, the surface area decreased the particle size, due to the collapse by micro-bubbles occurred and formation of crystal enhancement. Different characterizations have been carried out for "as-prepared" composites, such as X-ray diffraction (XRD) for checking the crystallinity, scanning electron microscopy (SEM) for structural morphology, energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectra (DRS), and photoluminescence (PL) spectra, and a standard three-electrode system has been used in a cyclic voltammetry test. The LaCdSe-GO-TiO2 has exposed a good photocatalytic activity in the presence and absence of several scavengers. Moreover, the applied high powersonic for hydrogen production can significantly influence the photocatalytic activity of LaCdSe-G-T. The implemented high powersonic produces electric field bridge and helps the conversion of electron from photon. [ABSTRACT FROM AUTHOR]

A novel decatungstate incorporated MOF of {[Cu(NPY)2(H2O)]2(W10O32)}·2DMF·3H2O (CuW–NPY; NPY = 3-amino-4,4′-bipyridine) has been synthesized by a diffusion method, and structurally characterized by elemental analyses, IR spectrum, UV–Vis spectrum, diffuse reflectance spectrum, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. CuW–NPY represents a novel decatungstate-based MOF with 1D quadrilateral channels (9.1 Å × 5.6 Å) constructed from Cu–NPY square grids and [W10O32]4− polyoxoanions via strong intermolecular hydrogen bonds and electrostatic interactions. Interestingly, CuW–NPY exhibits remarkable photocatalytic activities for the oxidation of cyclohexane to cyclohexanol and cyclohexanone with O2 under visible-light irradiation. The successful synthesis of CuW–NPY not only enriches decatungstate-based hybrid materials, but also represents the advantages of the decatungstate incorporated MOF for the selective oxygenation of organic compounds by O2. [ABSTRACT FROM AUTHOR]

In this investigation, a nanocomposite made of CuO/Fe2O3 mixed oxides was fabricated as a visible-light-responsive nanocomposite via a one-pot program. The photocatalytic efficacy of the manufactured material was checked via accomplishing the photocatalytic remediation of ciprofloxacin (CIP). Incorporation of 3 wt.% CuO to Fe2O3 was sufficient to bring about an efficient photocatalyst with declined bandgap energy. 0.9 gL–1 of the fabricated heterojunction was able to completely destroy CIP when irradiated by Vis light for 40 min. The appreciative photocatalytic enhancement of the accomplished heterojunction could be connected with the enrichment of the absorbed Vis light as well as the hindrance of the recombination amid photo-engendered charge carriers. This probe is a good application to develop heterojunction of excellent capability for the photocatalytic destruction of CIP beneath Vis light irradiation. [ABSTRACT FROM AUTHOR]

CdS/g-C3N4 (CdS/CN) type II heterojunction photocatalyst was prepared by an improved successive ionic layer adsorption and reaction process. TEM results show that the CdS nanoparticles (CdS NPs) were successfully loaded on the surface of CN. The results of PL and PEC display that the construction of CdS/CN heterojunction benefits the transmission of the photogenerated carriers and effectively inhibits the photogenerated carrier recombination in photocatalytic process. The photodegradation experiments exhibit that the 3-CdS/CN photocatalyst possesses the highest photodegradation performance over the other samples. The yields of H2 and CH4, in the presence of the best CdS/CN photocatalyst (1-CdS/CN) are 50 and 13 times stronger, respectively, than in the case of the pure CN in the photoreduction process of CO2. The CN coupling effectively improves the photocatalytic performance of CdS-based photocatalyst and inhibits the hole-induced photocorrosion of CdS NPs. A possible type II heterojunction photocatalytic mechanism has been provided. [ABSTRACT FROM AUTHOR]

Synthesis of new mixed anion compounds under visible light has been considered as an elegant strategy of photocatalyst development for efficient solar light harvesting applications. Through combined experimental and theoretical studies, we show that a new single layer Sillen-Aurivillius perovskite Bi4Ti0.5W0.5O8Cl is a good photocatalyst under visible light. This compound prepared by a solid-state reaction method has an energy gap of 2.36 eV and the visible-light-driven photocatalytic activities for degrading Rhodamine B are much better than Bi4NbO8Cl. We conclude from density functional theory calculations that its promising water-splitting application is due to its direct band gap and more stronger hybridization between Bi-6s and O-2p orbitals than Bi4NbO8Cl.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Polyoxometalates arise as significant catalysts in the field of organic chemistry due to their diverse properties and functions. Recent progress based on experimental evidence and density functional theory (DFT) calculations provides valuable information to demystify the chemistry of decatungstate anion, W10O324−. Particularly, functionalization of aldehydes by homolytic C–H bond cleavage can be efficiently achieved when it is catalyzed by this polyoxometalate. Two reaction mechanisms have been formulated to account for the role of W10O324− in organic chemical reactions: the single electron transfer and the hydrogen atom transfer (HAT) mechanisms. In this contribution, the HAT pathway for the acylation of dimethyl maleate is experimentally and quantum-chemically explored in detail. Results based on DFT calculations under the unrestricted formalism suggest that the acylation occurs in a barrierless process upon the formation of the lowest-in-energy triplet excited state of W10O324−. These outcomes agree well with the experimental evidence since the acylated adduct was produced at a 90% yield; in this regard, side reactions like radical couplings and decarbonylation resulted in less competitiveness. The current work may therefore help in the comprehension of the mechanistic details leading to the synthesis of organic compounds photocatalyzed by polyoxometalates, even under solar radiation. [ABSTRACT FROM AUTHOR]

Various human activities like mining and extraction of mineral oils have been used for the modernization of society and well-beings. However, the by-products such as petrochemical wastes generated from such industries are carcinogenic and toxic, which had increased environmental pollution and risks to human health several folds. Various methods such as physical, chemical and biological methods have been used to degrade these pollutants from wastewater. Advance oxidation processes (AOPs) are evolving techniques for efficient sequestration of chemically stable and less biodegradable organic pollutants. In the present review, photocatalytic degradation of petrochemical wastes containing monoaromatic and poly-aromatic hydrocarbons has been studied using various heterogeneous photocatalysts (such as TiO, ZnO and CdS. The present article seeks to offer a scientific and technical overview of the current trend in the use of the photocatalyst for remediation and degradation of petrochemical waste depending upon the recent advances in photodegradation of petrochemical research using bibliometric analysis. We further outlined the effect of various heterogeneous catalysts and their ecotoxicity, various degradation pathways of petrochemical wastes, the key regulatory parameters and the reactors used. A critical analysis of the available literature revealed that TiO is widely reported in the degradation processes along with other semiconductors/nanomaterials in visible and UV light irradiation. Further, various degradation studies have been carried out at laboratory scale in the presence of UV light. However, further elaborative research is needed for successful application of the laboratory scale techniques to pilot-scale operation and to develop environmental friendly catalysts which support the sustainable treatment technology with the 'zero concept' of industrial wastewater. Nevertheless, there is a need to develop more effective methods which consume less energy and are more efficient in pilot scale for the demineralization of pollutant. [ABSTRACT FROM AUTHOR]

Fabrication of mesoporous ZnO nanorods photocatalysts exploiting a facile one-pot regime of zinc methoxide and F127 triblock copolymer as a surfactant was conducted. The impact of decoration with platinum on the photocatalytic efficacy, crystallinity, morphology, and physical aspects of mesoporous Pt@ZnO nanorods accommodating various proportions of Pt was interrogated. TEM micrographs affirmed that the fabricated mesoporous ZnO nanorods displayed nanorods architecture and platinum was doped on the surface of mesoporous ZnO nanorods as dots. The measured lattice spacing of the (002) plane of ZnO was found to be about 0.270 nm, affirming the development of the ZnO lattice architecture. On the other hand, the consistent lattice spacing of the (111) plane of Pt was 0.220 nm, endorsing the progression of the metallic platinum lattice architecture. Evidently, the surface area possessed by the fabricated mesoporous ZnO nanorods was 200 m2/g; up to our knowledge, this large surface area wasn't attained previously. Furthermore, the average pore diameter and the total pore volume possessed by the fabricated mesoporous ZnO nanorods photocatalyst were 6.90 nm and 0.140 cm3/g, respectively. Ciprofloxacin (CIP) was photocatalytically degraded adopting mesoporous ZnO nanorods photocatalyst with a performance of 10%, whereas the photocatalytic performance toward CIP destruction was enhanced up to 100% upon doping ZnO nanorods photocatalyst with 0.6 wt.% Pt. Also, doping of the mesoporous ZnO nanorods photocatalyst with 0.6 wt.% Pt enhanced the photocatalytic degradation rate by 14 times compared with that of mesoporous ZnO nanorods photocatalyst. This conclusion could be attributed to the development of a high concentration of hydroxyl radicals, the accelerated dissipation of ciprofloxacin molecules to the active centers of the developed photocatalyst in addition to the reduced light scattering owing to the large surface area and high pore volume of the photocatalyst. [ABSTRACT FROM AUTHOR]