Oxide Photocatalysts Research Articles

Synthesis of BiOBr/graphene oxide photocatalyst assisted by sodium dodecyl sulfate for efficient degradation of organic pollutants

Surfactant‐assisted synthesis of photocatalysts for water treatment has received extensive attention from researchers. In this paper, a novel and efficient BiOBr/graphene oxide (BiOBr/GO) photocatalyst assisted by sodium dodecyl sulfate (SDS) was synthesized by a simple solvothermal method. Compared with use of other surfactants, like polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), BiOBr/GO (SDS) shows outstanding photocatalytic degradation activity under optimal conditions: The degradation rate constants of BiOBr/GO (SDS) for oxytetracycline (OTC), tetracycline hydrochloride (TCH), brilliant blue (BB), and Rhodamine B (RhB) are 0.073, 0.057, 0.166, and 0.626 min−1, which are 2.8, 1.8, 9, and 1.5 times larger than pure BiOBr, respectively. In addition, after five cycles, BiOBr/GO (SDS) exhibits superior cycling stability. The enhanced photocatalytic performance can benefit from the introduction of SDS and GO. With the assistance of SDS in the preparation process, BiOBr/GO (SDS) nanosheets have good adsorption performance and dispersion effect, which is favorable for raising their specific surface area. Meanwhile, the electron capture effect of GO improves the transfer and separation efficiency of photogenerated carriers. Moreover, the possible degradation pathway for TCH is identified through liquid chromatography–mass spectrometry (LC–MS). This research can become a valuable reference for synthesizing photocatalysts with visible light response to degrading organic pollutants such as antibiotics and dyes.

Silver nanoparticles-promoted bismuth titanate perovskite nanosheets photocatalyst for water purification

Photocatalysis is a recognized approach in the detoxification of pollutants and in water splitting. Such process is more appealing when it is driven by visible or solar light. In this context, we synthesized bismuth titanate perovskite oxide (Bi4Ti3O12, BTO) photocatalyst by sol–gel hydrothermal process. The resulting BTO materials was affected by the titania source and by the synthesis medium pH parameter. Titanium butoxide [Ti(n-BuO)4] was much better than titanium isopropoxide [Ti(i-PrO)4] in producing regular nanosheets with higher surface area, while 75 ml of 5.0 M sodium hydroxide was the optimum concentration for the synthesis of regular, thin, porous, almost equal size nanosheets. The photocatalytic activity of BTO was improved by loading silver nanoparticles (AgNPs) by photo-assisted reduction. The optimum weight percent of loading AgNPs was found to be 1.5 % because it led to the highest light absorbance, the smallest band gap energy, the minimum rate of electron-hole recombination. The photocatalytic degradation efficiency of 1.5 wt% Ag/BTO reached as high as 99.0 % of rhodamine B (RhB, 100 ml, 6 ppm of initial concentration) under 70 min of irradiating visible light (>420 nm). Moreover, pH had a strong influence on the photocatalytic activity of 1.5 wt% Ag/BTO, with pH = 3.0 was the optimum, owing to its impact on the interaction between the positively-charged photocatalyst surface and the negatively-charged RhB molecules. It was found that superoxide radicals played key role in the photocatalytic activity.

MXene quantum dots decorated g-C3N4/BiOI heterojunction photocatalyst for efficient NO deep oxidation and CO2 reduction

The photocatalytic performance of g-C3N4 is greatly limited by the severe charge recombination due to its s-triazine unit structure. Hence, enhancing the separation of photogenerated carriers is the pivotal factor for high-efficiency photocatalysis of g-C3N4. In this work, we construct a MXene quantum dots (MQDs) decorated BiOI/g-C3N4p-n heterojunction photocatalyst. The interfacial charge separation and transfer are substantially promoted, due to the synergistic effect of the internal electric field (IEF) of BiOI/g-C3N4 heterojunction and strong electron-withdrawing capability of MQDs. Furthermore, the introduction of BiOI with a low band gap and MQDs with large specific areas and rich surface terminals lead to enhanced light absorption and active sites. As a result, the ternary g-C3N4/MQDs/BiOI photocatalyst achieves a much higher NO removal rate of 42.23 % and discharges less NO2 intermediate than the individual and binary ones. Meanwhile, the g-C3N4/MQDs/BiOI photocatalyst also exhibits the most effective CO2 photoreduction, with a CO production rate of 57.8 μmol·g−1·h−1 and a CH4 production rate of 3.6 μmol·g−1·h−1, surpassing all other photocatalysts in this study. In addition, the designed composite photocatalyst shows remarkable stability. The photocatalytic mechanisms are studied by the trapping experiment and in-situ Fourier Transform Infrared (FTIR) Spectra. This work paves a new avenue for enhancing charge separation and thus improving performances of g-C3N4-based photocatalysts by integrating a p-n heterojunction and a co-catalyst, which would accelerate commercial deployment of emerging photocatalysts.

A Photoinduced Annulation Strategy Towards a Novel Polycyclic Heteroaromatic Chromophore: Scope, Mechanism, Properties and Applications.

This article reports a detailed mechanistic and kinetic study of an unusual photoreaction leading to the (diazonia)tetrabenzonaphthacene skeleton. The photo‐triggered double intramolecular nucleophilic aromatic substitution (SNAr∗) has been investigated by varying the leaving groups. Photoreaction quantum yields have been determined and mechanistic insights have been supported by theoretical calculations using DFT and TD‐DFT methods. Additionally, we show that this light‐triggered formed diazonia constitutes a potent photosentitizer with a singlet oxygen generation quantum yield of 55 %, both in organic solvents and in water, which is an extremely relevant value in view of PDT applications or use as an oxidation photocatalyst in aqueous media. Once again, the experimental observations were supported by TD‐DFT calculations showing a large density of triplet states below the S1 excited state along with large spin‐orbit couplings. The reaction is not restricted to solutions but can also occur in solid PDMS matrices thus allowing for photochemical encoding of information that will progressively vanish upon prolonged UV‐exposure.

Enhanced photocatalytic activity of green synthesized zinc oxide nanoparticles using low-cost plant extracts

Developing stable and highly efficient metal oxide photocatalysts remains a significant challenge in managing organic pollutants. In this study, zinc oxide nanoparticles (ZnO NPs) were successfully synthesized using various plant extracts, pomegranate (P.M), beetroot roots (B.S), and seder, along with a chemical process. The produced ZnO NPs were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), Field Emission Scanning Electron Microscope (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM), and Surface Area. For all prepared samples, the results indicated that the composition of the plant extract affects several characteristics of the produced particles, such as their photocatalytic properties, energy bandgap (Eg), particle size, and the ratio of the two intensity (0 0 2) and (1 0 0) crystalline planes. The particle size of the produced NPs varies between 20 and 30 nm. To examine NPs' photocatalytic activity in the presence of UV light, Methyl Orange (MO) was utilized. The Eg of ZnO synthesized by the chemical method was 3.16 e. V, whereas it was 2.84, 2.63, and 2.59 for P.M, Seder, and B.S extracts, respectively. The most effective ZnO NPs, synthesized using Beetroots, exhibited a degradation efficiency of 87 ± 0.5% with a kinetic rate constant of 0.007 min−1. The ratio of the two intensity (0 0 2) and (1 0 0) crystalline planes was also examined to determine a specific orientation in (0 0 2) that is linked to the production of oxygen vacancies in ZnO, which enhances their photocatalytic efficiency. Furthermore, the increase in photocatalytic effectiveness can be attributed to the improved light absorption by the inter-band gap states and effective charge transfer.

Facile synthesis of Pt clusters decorated TiO2 nanoparticles for efficient photocatalytic degradation of antibiotics

AbstractTiO2 has attracted much attention in the field of photocatalytic degradation of antibiotics due to its good photostability, nontoxicity, and low cost. However, the rapid recombination of photogenerated carriers limits the further improvement of its photocatalytic activity. Here, a facile microwave‐assisted hydrothermal method has been developed to prepare Pt clusters decorated TiO2 nanoparticles. Pt clusters ranging in size from 1 to 2 nm are uniformly distributed across the surface of the TiO2 matrix. A pronounced charge transfer phenomenon is discernible between the Pt and TiO2 components. It is revealed that the charge transfer enables faster transfer and separation of photogenerated electrons and holes, which are beneficial for the improvement of photocatalytic degradation of both ofloxacin and levofloxacin. The degradation capability can be attributed to the efficient generation of •OH or •O2− species within the solution. The parallel adsorption model of TiO2 on antibiotic molecules is verified, and the degradation reaction pathway has been elucidated. This work provides a facile method for optimizing the performance of TiO2 photocatalysts, which can be extended to other oxide photocatalysts.

A comprehensive review on the application of semiconductor nanometal oxides photocatalyst for the treatment of wastewater

A comprehensive review on the application of semiconductor nanometal oxides photocatalyst for the treatment of wastewater

Quantitative Analysis of the Synergy of Doping and Nanostructuring of Oxide Photocatalysts.

In this paper, the effect of doping and nanostructuring on the electrostatic potential across the electrochemical interface between a transition metal oxide and a water electrolyte is investigated by means of the Poisson-Boltzmann model. For spherical nanoparticles and nanorods, compact expressions for the limiting potentials at which the space charge layer includes the whole semiconductor are reported. We provide a quantitative analysis of the distribution of the potential drop between the solid and the liquid and show that the relative importance changes with doping. It is usually assumed that high doping improves charge dynamics in the semiconductor but reduces the width of the space charge layer. However, nanostructuring counterbalances the latter negative effect; we show quantitatively that in highly doped nanoparticles the space charge layer can occupy a similar volume fraction as in low-doped microparticles. Moreover, as shown by some recent experiments, under conditions of high doping the electric fields in the Helmholtz layer can be as high as 100 mV/Å, comparable to electric fields inducing freezing in water. This work provides a systematic quantitative framework for understanding the effects of doping and nanostructuring on electrochemical interfaces, and suggests that it is necessary to better characterize the interface at the atomistic level.

Mesoporous aluminosilicate materials supported zinc oxide photocatalytic degradation of pharmaceutical pollutants

The current study focuses on the creation of catalysts that have several uses. Supports for attaching ZnO catalysts are made of mesoporous alumino-silicate materials with varying SiO2/Al2O3 ratios (type Siral), and the amount of Al in them ranges from 20 % to 70 %. The alumino-silicate support materials are great for loading active components because they have a lot of surface area, a well-defined regular structure, and few mesopores that are spread out. We carry out the synthesis of the mesoporous alumino-silicate-supported zinc oxide photocatalyst (Siral/ZnO) using a mechano-chemical grinding approach. Different characterization methods, such as UV–visible spectroscopy, X-ray powder diffraction (XRD), SEM, and Brunauer-Emmett-Teller (BET), evaluate the properties of the heterogeneous catalysts and the effectiveness of ZnO addition. We use these supports to enhance their catalytic efficiency by examining responses related to the decomposition of pharmaceutical contaminants and pigments like Ibuprofen (IBP). The finding results revealed that mesoporous structure of Siral/ZnO NCs with an average crystallite size of 1–50 nm with the Type IV N2 adsorption and desorption isotherms show a noticeable photocatalytic activity under UV–visible light irradiation. The efficiency of the photo-degradation increases with increasing the weight percentage from 5 wt% to 60 wt% of ZnO NPs, and it reaches 85.18 % for Siral70/60 % ZnO after 4 h. Siral/ZnO NCs photocatalysts exhibit exceptional photostability and reusability when it comes to the degradation of organic molecules.

Efficient photocatalytic degradation of ethylenethiourea with zinc oxide photocatalysts: Parameters optimization, mechanism insight, exploration of degradation pathways and toxicity assessment

Traditional advanced oxidation processes (AOPs) for the removal of toxic and refractory ethylenethiourea (ETU) is uneconomical because of the demand for continuous chemical input and full-scale systems. Herein, ETU was efficiently mineralized without sacrificial reagents for the first time through the utilization of ZnO nano-photocatalysts which were synthesized by the adjustment of ratio between the precursor ZnCl2 and alkaline source KOH during hydrothermal process. Compared to other ZnO samples, ZnO-1/3 (1:3 molar (M) ratio of ZnCl2 to KOH) exhibited higher apparent rate constant (0.00661 min−1) towards the degradation of ETU because of more effective electron-hole separation. The optimum conditions for ETU degradation (ZnO-1/3 dosage of 0.4 g/L, initial ETU concentration of 10 mg/L and photocatalytic reaction temperature of 35 °C) were acquired according to the outcome of the response surface methodology (RSM) based on the Box-Behnken design (BBD), and the predicted maximum removal efficiency of ETU reached 93.17 % and was consistent with the experimental results under this optimum conditions. The h+ and •OH were proved to the main reactive species during the photocatalytic process by the free radical capture experiments and electron spin resonance (ESR) analysis. Furthermore, the possible degradation pathways of ETU were suggested based on the identified degradation intermediates, and the reduced toxicity of intermediates was also demonstrated through the quantitative structure–activity relationship (QSAR) prediction and the growth of mung bean seedlings. Hence, photocatalysis with ZnO can be regarded as a promising alternative for ETU elimination.

Built-in electric field mediated S-scheme charge migration and Co-N4(II) sites in cobalt phthalocyanine/MIL-68(In)-NH2 heterojunction for boosting photocatalytic nitric oxide oxidation

The efficiency of photocatalytic Nitric Oxide(NO) oxidation is limited by the lack of oxygen(O2) active sites and poor charge carrier separation. To address this challenge, we developed a molecular Cobalt Phthalocyanine modified MIL-68(In)–NH2 photocatalyst with a robust Built-in electric field(BIEF). In the 2 % CoPc-MIN sample, the BIEF strength is increased by 3.54 times and 5.83 times compared to pristine CoPc and MIL-68(In)–NH2, respectively. This BIEF facilitates the efficient S-scheme charge transfer, thereby enhancing photogenerated carrier separation. Additionally, the Co-N4(II) sites in CoPc can effectively trap the separated photoexcited electrons in the S-scheme system. In addition, the Co-N4(II) sites can also serve as active sites for O2 adsorption and activation, promoting the generation of superoxide radical (O2–), thereby driving the direct conversion of NO to nitrate(NO3–). Consequently, the 2 % CoPc-MIN sample exhibits a remarkable photocatalytic NO removal efficiency of 79.37 % while effectively suppressing the formation of harmful by-product nitrogen dioxide(NO2) to below 3.5 ppb. This study provides a feasible strategy for designing high-efficiency O2 activation photocatalysts for NO oxidation.

Oxygen vacancy-suppression strengthened the internal electric field in ZnIn2S4/BiVO4 S-scheme heterojunction to boost photocatalytic removal of aqueous pollutants

The impact of internal electric field intensity (IEF) within step-scheme (S-scheme) heterojunctions is profound on photocatalytic performance. Furthermore, the presence of oxygen vacancies in the photocatalysts has a significant influence on their photocatalytic characteristics. Thus, a ZnIn2S4/BiVO4 S-scheme heterojunction was strategically engineered for photocatalytic degradation. The modulation of oxygen vacancy levels in the oxidation photocatalyst (OP) was utilized to adjust the IEF within the S-scheme heterojunctions. BiVO4 with controlled oxygen vacancies was synthesized using a simple approach, and the impact of oxygen vacancies on the charge transfer across the heterojunction was thoroughly examined. Subsequently, various characterization results, verified that the IEF in the heterojunction with suppressed oxygen vacancy levels (10 %BV-600) was stronger, while those with elevated vacancy levels (10 %BV-400) showed weaker IEFs. Comprehensive results confirmed that the S-scheme heterojunction is formed between ZnIn2S4 and BiVO4. Under visible irradiation, the 10 %BV-600 sample demonstrated remarkable photocatalytic activity, achieving a 96.4 % degradation of methyl orange within 60 min. Intriguingly, the rate constants for methyl orange removal for the 10 %BV-600 sample were approximately 3 and 27 times greater than those of the individual ZnIn2S4 and BiVO4, respectively. Moreover, the photocatalytic performance of the 10 %BV-400 sample, which had a lower IEF, was inferior to that of the 10 %BV-600 sample. These results underscore the superior photocatalytic capabilities of heterojunctions with a strengthened IEF due to suppressing oxygen vacancy. This work provides insights into the role of oxygen vacancy in regulating IEF intensity in heterojunctions.

Visible‐light‐driven selective aerobic oxidation of olefins over bifunctional photocatalyst Cu‐BTC‐TiO2 in water

Metal organic frameworks (MOFs) as semiconductor‐like materials, are considered to be promising photocatalysts for heterogeneous phtotocatalytic oxidation of styrene. Herein, copper‐based MOFs and titanium dioxide composite bifunctional photocatalyst (Cu–benzene‐1,3,5‐tricarboxylate‐titanium dioxide, Cu‐BTC‐TiO2) wereas synthesized, and the selective oxidation of styrene was achieved under mild conditions of oxygen and water. Cu‐BTC‐TiO2 nanoparticles (NPs) exhibited more than three times higher styrene conversion than Cu‐BTC and TiO2 individually under same condition, and the desired product benzaldehyde can be obtained with up to 82% yield. The improved performance may be attributed to the acid site of Cu‐BTC, which is conducive to the adsorption and activation of styrene. In addition, the formation of heterojunction between Cu‐BTC and TiO2 can regulate the band gap of photocatalyst, which is favorable for light absorption, and facilitate the separation, transportation and utilization of photogenerated electron holes. The present protocol features good functional group tolerance, mild reaction conditions, and the reusability of catalyst.

Construction of novel Cd-based coordination polymer composite with enhanced solar light driven photocatalysis toward simultaneous chlortetracycline degradation and Cr(VI) reduction

Coordination polymers (CPs) can be easily functionalized to prepare composite materials to improve their properties. In this study, we report the designed of iron-modified Cd-based coordination polymer composite (Fe@Cd-CP) and photocatalytic activity in removal of antibiotic contaminant and heavy metal. The two-dimensional (2D) layered {[Cd(4-padpe)(1,3-BDC)]⋅H2O}n (Cd-CP) was firstly synthesized by hydrothermal method. Interestingly, the introduction of iron significantly improved photocatalytic performance compared with the pristine Cd-CP. The Fe@Cd-CP composites were applied as bi-functional photocatalysts for simultaneous oxidation of chlortetracycline (CTC) and reduction of Cr(VI) under sunlight irradiation. Based on the detailed experiments, the enhanced photocatalytic performance could be mainly explained by the introduction of iron, resulting in enhanced the harvesting ability of visible light and facilitated the photogenerated electrons and holes separation. Besides, the results clearly displayed that the Fe@Cd-CP composite had good stability and reutilization. The free radical scavenging experiments revealed that ·OH, ·O2-, and h+ jointly participated in the oxidation degradation CTC and the photogenerated electrons took part in the reduction of Cr(VI). Our work proposed a functional strategy for constructing Cd-CP based photocatalyst for environmental remediation.

Defects induced SnOx-TiO2 nanocomposite thin films for improved visible light driven photocatalysis and photoelectrochemical applications

Advanced oxidative removal of organic pollutants from water bodies using nanoparticles of metal oxide photocatalysts is a concurrent hot topic. In the present study, SnOx-TiO2 heterogeneous nanocomposite thin film photocatalysts have been synthesized using SnO and TiO2 precursors by binder-free doctor blade technique. X-ray diffraction was used to confirm the presence of anatase TiO2 as a major phase at elevated temperatures. Raman spectra analysis confirmed phase transformation and defect induction. X-ray photoelectron spectroscopy was utilized to determine the purity and chemical condition of the synthesized thin films. The porous nature of the thin film surface was observed using field emission scanning electron microscopy. UV–Vis-NIR spectroscopy results showed a reduction of bandgap from 3 eV to 2.6 eV with enhanced light absorption. The superior oxygen evolution reaction, redox nature and charge carrier generation were demonstrated using photo-electrochemical techniques. Improved photoresponse of the photocatalysts was observed using chrono-amperometry technique. The superior visible light-driven photocatalytic activity of the samples was demonstrated utilizing cationic and anionic model pollutant dyes. The reusability of the catalyst is ensured through successive photodecomposition processes. These results show a facile fabrication of defects induced heterogenous nanocomposite photocatalyst thin films with improved visible light activity.

Enhanced photocatalytic degradation of Congo red dye into safe end-products over ZnO@polyaniline/coal composite as low cost catalyst under visible light: Pathways and ecotoxicity

ZnO@polyaniline/coal nanocomposite (ZnO@PANI/C) was synthesized and characterized by different analytical techniques as potential enhanced photocatalyst for the successful oxidation of Congo red dye (CR) into eco-friendly end-products. The investigated CR concentration (5 mg/L) was completely decolorized after 120 min, 100 min, 80 min, and 40 min after the incorporation of ZnO@PANI/C dosages at 0.2 g/L, 0.3 g/L, 0.4 g/L, and 0.5 g/L, respectively. The synergetic studies demonstrate a significant impact of the integrated components (coal, polyaniline (14.2 % oxidation of CR), ZnO (21.6 % oxidation of CR), 43.7 % (PANI/C oxidation of CR), and 64.3 % (ZnO/C oxidation of CR)) on the catalytic activity of ZnO@PANI/C (100 % oxidation of CR), which is higher than that of the individual components. The investigation of TOC content reflects that the complete mineralization can be detected after 100 min and validates the formation of different species of intermediates started by sodium-3-(phenyl diazenyl) naphthalene-1-sulfonate until detecting ethyl benzene. The findings of the oxidizing trapping tests demonstrate the controlling impact of the hydroxyl radicals as the oxidation in the presence of its trapping reagent (Isopropanol) declined to 8.6 %. The oxidation pathway of CR over ZnO@PANI/C involved a progressive series of decarboxylation and dihydroxylation ended by ethylbenzene, which in turn produced nontoxic products such as H2O and CO2. The eco-toxicity tests reflect the efficiency of the photo-oxidation of CR contaminants by ZnO@PANI/C in reducing acute toxicity (LC50 and EC50 > 100) and chronic (ChV > 10) toxicities of CR dye after 60 min of remediation.

Machine learning accelerates the screening of efficient metal-oxide catalysts for photocatalytic water splitting

Photocatalytic water splitting represents a sustainable avenue for hydrogen production, yet the traditional trial-and-error approach for identifying efficient photocatalysts among numerous candidates is cumbersome. In this paper, we introduce a machine learning (ML)-driven approach for rapid screening of promising metal oxide photocatalysts for hydrogen generation. This methodology comprises three key steps: the construction of a comprehensive material library, ML-accelerated material screening, and Density Functional Theory (DFT) calculations for verification. Through this process, we successfully identify ten metal oxides with good energy levels and charge carrier transport properties from an initial library of 860 candidates. Notably, CsYO2 emerges as a standout candidate, exhibiting excellent photocatalytic water-splitting performance on its (001) crystal face, with Y atoms identified as active sites through DFT calculations. This study demonstrates the efficacy of applying machine learning to the precise and rapid screening of vast material databases, paving the way for discovering novel and efficient photocatalysts.

Photocatalytical Degradation of Methyl Orange using laboratory prepared Copper Oxide photocatalyst

Photocatalytical Degradation of Methyl Orange using laboratory prepared Copper Oxide photocatalyst

Isomolar high-entropy engineering and Ac-coordination regulated nanocubic hydroxystannate for synergistic adsorption-photocatalytic acetaldehyde abatement under anoxic conditions

High-entropy materials have attracted increasing attention in many applications due to their unusual properties, yet little is known about the effects of cationic ratios and anionic ligands on their catalytic activity. Herein, a novel isomolar high-entropy and Ac-coordinated hydroxystannate nanocube (iHEOH-Ac) is fabricated using NaOH as precipitant and acetate anion as ligand in one step. The unique strategy simultaneously employing isomolar high-entropy engineering and Ac coordination in iHEOH-Ac synergistically facilitates the formation of oxygen vacancies and acid sites and significantly enhances optical absorption, charge separation and acetaldehyde activation, leading to the highest amount of ROS (•OH and •O2– and h+). The synergistic adsorption-photocatalytic performance of iHEOH-Ac in acetaldehyde abatement outperforms its net photocatalytic mode and other counterparts, with maximum removal ratio up to ∼ 100% under anoxic conditions and reversible deactivation of ∼ 10% over 360 min. This work not only sheds light on the enhancement mechanism on the acetaldehyde oxidation performance through isomolar high-entropy and Ac-coordinated strategy, but also successfully regulates the acetaldehyde oxidation pathways by the reaction mode and anionic coordination environment, providing a new route for the design of high-performance acetaldehyde oxidation photocatalysts under anoxic environments.

Efficient Photocatalytic Partial Oxidation of Aromatic Alcohols by Using ZnIn2S4 under Green Conditions.

The ternary chalcogenide ZnIn2S4 (ZIS) has been synthesized by a simple hydrothermal method in which the carcinogen thiacetamide, universally used as a precursor, has been, for the first time, replaced successfully with the harmless thiourea. ZIS has been used as photocatalyst for the partial oxidation of different aromatic alcohols to their corresponding aldehyde in water solution, under ambient conditions and simulated solar light irradiation. The photocatalytic performance of ZnIn2S4 was better than TiO2 P25. In the presence of ZIS for 4-methoxybenzyl alcohol, piperonyl alcohol, and benzyl alcohol, a selectivity towards the corresponding aldehyde of 99 % for a conversion of 46 %, 75 % for a conversion of 81 %, and 87 % for a conversion of 25 %, respectively, was obtained. For the same alcohols a selectivity of 19 % for a conversion of 41 %, 19 % for a conversion of 13 %, and 16 % for a conversion of 26 %, was observed in the presence of TiO2 P25.