The development of a visible light-responsive photocatalyst for the synthesis of fine chemicals is a promising strategy for sustainable chemical transformations. In this work, a series of bismuth molybdate (BMO) materials were synthesized via hydrothermal or solvothermal methods using H2O or ethylene glycol as solvent with varying amounts of urea, and applied for the photocatalytic reduction of nitrobenzene to aniline in alcohol. The characterization results revealed that the amount of urea significantly influenced the phase composition and morphology of BMO materials synthesized in H2O. In contrast, the addition of urea to ethylene glycol up to a molar urea to Bi ratio of 10 to 1 did not alter the phase composition, which remained as pure Bi2MoO6. However, the presence of urea affected its morphology, increasing the amount of urea led to larger agglomerated spheres and eventually to broken spherical structures. The BMO materials synthesized in ethylene glycol show much higher photocatalytic activity for nitro group reduction than their counterparts prepared in water. Furthermore, the obtained results show that the type of alcohol used has a significant impact on the aniline formation as well as the transformation of the formed intermediates. When using methanol, complete nitrobenzene conversion was reached within 2 h of blue LED irradiation with 94% aniline selectivity. Finally, a mechanism for the reduction of nitrobenzene in alcohols over Bi2MoO6 under blue LED light irradiation was suggested.

Alkoxycarbonylation of olefins is a pivotal transformation in the production of esters; however, attaining high regioselectivity in this transformation, specifically using industrially relevant aliphatic olefins, remains a formidable challenge. To date, this objective has been achieved exclusively through the integration of precious Pd catalysts and costly phosphine ligands in a pressurized CO environment at high temperatures. In this study, we present a novel cobalt-catalyzed light-driven protocol for achieving excellent regioselectivity under mild conditions. Specifically, we demonstrate the efficacy of converting propylene, as well as terminal and internal linear olefins, to the corresponding terminal esters with over 90% regioselectivity, accompanied by a wide range of alcohols. Control experiments and DFT computations reveal that light promotes the formation and maintains the concentration of the key species HCo(CO)(3).

A novel rapid solvent-free approach for the preparation of a nanocomposite containing the solid solution of zinc indium sulfide (ZIS), binary indium sulfide and a small amount of zinc sulfide is reported herein. In just 15 min of processing the elemental mixture of zinc, indium and sulfur in a planetary ball mill, a considerable amount of nanocrystalline ZIS, with an admixture of binary intermediates was obtained via mechanochemical synthesis (ZIS-15). The detailed investigation of lattice parameters via Rietveld refinement of the XRD data has shown the continuous shrinkage of unit cell upon incorporation of zinc into the lattice of indium sulfide, thus pointing to the formation of a solid solution. When milling was prolonged for a further 15 min (ZIS-30), the color changed from brown to orange and the amount of ZIS further increased, albeit it was not possible to completely transform binary intermediates into ZIS. The zeta potential values were documented to be -21.6 and -11.5 mV for ZIS-15 and ZIS-30, respectively, documenting different surface properties. The difference is most probably caused by the higher content of binary indium sulfide in ZIS-15. The obvious difference was evidenced also in the photocatalytic activity to decompose rhodamine B dye, which was 2.5 times higher in the case of ZIS-15, thus the presence of higher number of binary sulfides seems to be beneficial. ZIS-15 was capable of degrading also noncolored diclofenac sodium. Thus, the actual inability to achieve a complete conversion to ZIS in 30 min is used as a benefit to obtain a photocatalyst with better activity here. The proposed study also highlights a great suitability of solvent-free mechanochemical synthesis for the sustainable production of nanocrystalline semiconductor photocatalysts, as the calculated E-factor of 22.9 is much lower than when using traditional hydrothermal synthesis. This also accounts for the atom economy, as we are using only the reactants forming the product, whereas the classical chemistry uses salts.

The palladium-catalyzed Suzuki-Miyaura cross coupling reaction to forge carbon-carbon bonds fundamentally changes the practice of organic synthesis. Herein an isolated palladium catalyst supported on polymeric carbon nitride (Pd/PCN) for efficient cross coupling of bromobenzene and phenylboronic acid at room temperature is reported. It is demonstrated that the Pd/PCN catalyst with a 2 wt% Pd loading achieves the highest mole-specific activity. In addition, the size of supported Pd can strongly affect the reaction performance: the isolated Pd species exhibit higher activity compared to the Pd nanoparticles. The continuous flow tests demonstrate that the catalytic properties of the Pd/PCN catalyst strongly depend on the reaction atmosphere: Pd-catalyzed self-coupling of phenylboronic acid as a side reaction is more pronounced under an O2 flow than in an Ar flow. Detailed mechanistic investigations through in situ infrared spectroscopy reveal the role of the base K2CO3 in activating the phenylboronic acid.

This study introduces the innovative Bi4O5I2/Bi2O2.33 heterojunction for diclofenac (DF) degradation. Pharmaceutical pollutants, especially DF, pose significant threats to water sources, necessitating efficient treatment methods. Bi2O2.33, renowned for its unique ferromagnetic properties, emerges as a promising photocatalyst for pollutant degradation. Bi4O5I2, known for strong visible light absorption and stability, holds potential for environmental applications. Interestingly, the inclusion of titanium dioxide (TiO2) in the composite catalysts significantly influences their observed ferromagnetic properties, as revealed by Electron Paramagnetic Resonance (EPR) spectroscopy, by influencing the interactions within the Bi4O5I2/Bi2O2.33 heterojunction and influencing its structure, morphology, and spin behavior. This interaction results in enhanced EPR and Ferromagnetic Resonance (FMR) signals, indicating intriguing spin interactions, polarization effects, charge transfers, surface dynamics, and stabilized magnetic domains. While the enhanced ferromagnetism holds promise for efficient charge separation and potential applications in environmental remediation, the expected boost in visible light-driven activity was not fully realized. This limitation is attributed to TiO2 inherent inability to directly absorb visible light, hindering its utilization for enhanced photocatalysis within the heterojunction. Nevertheless, these findings elucidate the multifaceted role of TiO2 in modulating the magnetic properties of these catalysts, offering valuable insights for future advancements in the design of advanced photocatalysts for effective environmental remediation.

As a visible light-responsive photocatalyst with a unique structure, the development of bismuth molybdate (BMO) materials for the efficient degradation of pollutants has attracted considerable attention. In this work, BMO materials with molar Bi/Mo precursor ratios between 1.1:1 and 3.0:1 were synthesized by a solvothermal process using ethylene glycol as a solvent and subsequently calcined. To investigate the influence of this ratio on the structural, textural, and optical properties of the BMO materials, they were comprehensively characterized using complementary methods. The characterization results showed that the Bi/Mo ratio had no influence on the size of the spherical microstructure formed; however, it significantly affected the shape of the Bi2MoO6 nanostructure that builds the microstructure. In addition, at Bi/Mo ratios of 2.3:1 or higher, a heterojunction is formed, consisting of irregularly shaped Bi2MoO6 nanoplates and a Bi-rich phase with low Mo content. To assess the performance of the BMO materials, the model substances diclofenac sodium (DCF) and ciprofloxacin (CIP) were photocatalytically degraded by irradiation with blue LED light (lambda max = 467 nm). For BMO synthesized with a Bi/Mo ratio of 2.3:1 or higher, improved degradation and mineralization performance were observed. Within 180 min, 98% of the DCF was degraded, and the TOC content decreased by 80%. CIP was completely degraded during this period, and mineralization reached 44%. The boosted photocatalytic performance is attributed to the close contact between Bi2MoO6 and the Bi-rich Bi x Mo y O z phase, which creates an internal electric field, leading to improved charge transfer efficiency and suppressed photoelectron-hole recombination. Finally, experiments in recirculation mode were carried out to evaluate the photocatalytic stability of the synthesized BMO catalyst.

Titanium oxide semiconductors are considered effective photocatalysts for the degradation of organic pollutants. The photocatalytic activity of titanium dioxide is influenced by several factors, one of which is its phase composition, with anatase being considered the phase with the highest photocatalytic activity. In this work, a simple acid-assisted sol–gel process was used to synthesize a pure anatase phase by varying the synthesis and calcination temperature. The synthesized materials were characterized using various techniques and tested under simulated sunlight irradiation for the photocatalytic degradation of the drug diclofenac sodium (DCF), for which the pseudo-first-order apparent degradation rate constant and mineralization efficiency were determined. A pure anatase phase with high photocatalytic activity (up to 97% TOC removal) was obtained when TiO2 was synthesized at between 70 °C and 100 °C and calcined at between 400 °C and 500 °C. Furthermore, the obtained data were used to predict the optimal anatase synthesis and calcination temperatures for DCF removal using a response surface methodology (RSM) method. The model predicted a synthesis temperature of 71 °C and a calcination temperature of 440 °C, which should result in a pseudo-first-order DCF decay rate constant of 0.055 min−1 and a TOC removal rate of 100%. The experimentally determined values for the degradation rate (0.063 min−1) and TOC removal (97%) were in good agreement with the model’s predicted values.

Exfoliation into a 2D nanosheet structure can lead to enhanced surface activity and unique optical and electronic properties in polymeric carbon nitride (PCN). In this study, four common exfoliation strategies (liquid ultrasonication, thermal oxidation, hydrothermal oxidation, and chemical oxidation) were adopted, and their effects on the structural and electronic changes in PCN were analyzed in detail. This allows us to understand the relationship between the exfoliation mechanism and the structural/optical properties. Here, we demonstrate that the thermal and ultrasonic exfoliation methods can effectively reduce the thickness of PCN while preserving its original structure. In contrast, the chemical and hydrothermal treatments can strongly affect the morphology and structure of PCN, leading to a decreased performance in phenol photodegradation. Therefore, depending on the employed exfoliation method, the surface area, functionalization, band edge positions, charge carrier generation, and mobility are influenced differently up to the point where semiconducting behavior is entirely lost. Our results allow conclusions about the applicability of the different exfoliation methods to obtain distinct material properties for photocatalytic applications.

Photocatalytic transformation of organics is a promising alternative to conventional synthetic methodologies. ZnIn2S4 is active in photocatalytic redox reactions, but its performance is hindered by fast charge carrier recombination, and optimizing its properties through synthesis or modification is complicated. Herein, Zn-In-S based composites were prepared via a facile solvothermal method by varying the ratio of sulfide precursor (TAA) with a fixed Zn/ In molar ratio of 1: 2. The phase composition of the obtained materials depends on the amount of TAA. At lower ratios, composites consisting of crystalline In(OH)3 and unknown ZnxInySz phase were formed. Pure-phase ZnIn2S4 was obtained when the feed molar ratio of zinc and TAA was 1: 6 or higher. The photocatalytic oxidation of benzyl alcohol (BA) and reduction of nitrobenzene (NB) in a coupled system were applied to evaluate the activity of Zn-In-S-based composites. Under visible light irradiation, the ZnxInySz/ In (OH)3 composite (ZIS14) synthesized with a molar ratio of Zn to TAA of 1: 4 exhibited boosted and optimal performance compared to the bare ZnIn2S4 and other samples. After 5 hours of irradiation, the BA conversion and benzaldehyde (BAD) yield were 57 % and 55 %, respectively, and the NB conversion and aniline (AN) yield were 70 % and 35 %, individually, outperforming previous studies under similar experimental conditions. This work not only elucidates the photoredox process of BA and NB in one system, but also has significant implications for understanding the complex hydro/solvothermal processes involved in the fabrication of multicomponent sulfides.

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (⋅O2−) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron–hole separation, and larger specific surface area.

The nature of the support can fundamentally affect the function of a heterogeneous catalyst. For the novel type of isolated metal atom catalysts, sometimes referred to as single-atom catalysts, systematic correlations are still rare. Here, we report a general finding that Pd on nitride supports (non-metal and metal nitride) features a higher oxidation state compared to that on oxide supports (non-metal and metal oxide). Through thorough oxidation state investigations by X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), CO-DRIFTS, and density functional theory (DFT) coupled with Bader charge analysis, it is found that Pd atoms prefer to interact with surface hydroxyl group to form a Pd(OH) x species on oxide supports, while on nitride supports, Pd atoms incorporate into the surface structure in the form of Pd−N bonds. Moreover, a correlation was built between the formal oxidation state and computational Bader charge, based on the periodic trend in electronegativity.

The accumulation of active pharmaceutical ingredients in the aqueous environment is a serious problem that will become even more concerning in the future. In this work, the photocatalytic degradation of ciprofloxacin (CIP) in aqueous solution was assessed over P25-TiO2 coated open microchannels with gravity-driven flow under UV-A irradiation. The deposition of different amounts of TiO2 in the microchannels was carried out via a facile, selfdeveloped procedure. The degradation kinetics of ciprofloxacin was described via the Langmuir-Hinshelwood mechanism. Since the flow characteristics in the microchannel had influence on the concentration distribution of CIP in the microchannel, the coupled momentum and mass conservation law was solved numerically in MATLAB 2023a (2D case) as well as in ANYS Fluent 2023 R1 (2D and 3D cases). Although the implemented 2D model in MATLAB 2023a allowed the preliminary estimation of the selected kinetic parameters, namely adsorption equilibrium constant and specific Langmuir-Hinshelwood rate constant, the sensitivity of the model was not satisfactory which was attributed to the empirical correlations used for the estimation of the external mass transfer coefficient. The 2D and 3D models in ANSYS Fluent 2023 R1 predicted efficiently the outlet concentration of ciprofloxacin for different inlet CIP concentrations and liquid phase flow rates. Therefore, the as developed 2D and 3D models in ANSYS Fluent 2023 R1 can be used for the design of reactors containing coated microchannels with gravity-driven flow for photocatalytic degradation of active pharmaceutical ingredients.

This work aims the experimental and numerical characterization of gas–liquid flow in an open multichannel falling film microreactor containing 64 coated microchannels, and a split & curve structure for the flow distribution. The operating flowrate range, the flow distribution, and the residence time of the liquid in the single channels were assessed via self-designed pulse input tracer experiments.3D simulations based on Volume of Fluid (VoF) multiphase model were developed in ANSYS Fluent considering a representative section of a single microchannel. Simulation results indicate that backflow phenomena and an increase in film thickness along the channel length are the main reasons for the high film thickness observed experimentally. While flow rate has only a marginal effect on both processes, the plate inclination angle had considerable contribution in overflow and flow stability. Finally, the numerically calculated transversal wetted area was mainly determined by the defined GLS contact angle at the sidewalls.

In this study, magnetic MFe 2 O 4 (MFO, M = Ni, Co)/RGO heterogeneous catalysts have been synthesized by a facile solvothermal method. To characterize their morphological, structural, magnetic, and optical properties, the materials were analyzed by complementary chemical–physical methods. Moreover, the obtained results were compared with those obtained from pristine MFe 2 O 4 and individual synthesized RGO. The MFO/RGO composites are composed of thin RGO layers and approximatively spherical aggregates of small crystalline MFO nanoparticles. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride was applied to access the catalytic activity of the synthesized composites. Among these synthesized materials, NiFe 2 O 4 /RGO was highly active in this reaction. The combination of RGO layers and NiFe 2 O 4 nanoparticles is assumed to be responsible for its high activity. Furthermore, NFO/RGO was catalytically active for six cycles adding fresh 4-nitrophenol (4-NP) to the reaction mixture.

Photocatalytic CO 2 reduction was studied over SrTiO 3 -based catalysts in a high-purity gas-phase photoreactor. Depending on the catalyst composition different main products were obtained.

Using a series of ordered mesoporous TiO2 (om-TiO2) with and without Ce or Cu doping, the effects of structure, metal doping and residual template species in the structure are systematically evaluated in terms of products formed during a CO2 photoreduction process. It is found that the ordered mesoporous structure contributes significantly in the hydrogen evolution reaction from the splitting of gaseous water. No cocatalyst was needed to achieve high hydrogen yields. While carbon-containing products are also observed, the presence of remainders of the organic template used in the synthesis process does not allow an unambiguous identification of the source of products. Small amounts of metal doping do not majorly influence the hydrogen evolution, thus the mesoporous structure can eventually be identified as the main cause for the improved performance.

2D ZnIn 2 S 4 nanosheets were synthesized via a trisodium citrate-assisted hydrothermal method and used for the oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran and 5-formyl-2-furan with atmospheric O 2 under visible light irradiation.

Optimization based on mathematical models has received growing attention in materials science. The first part of the work aims to optimize the photocatalytic activity of CaTiO3 for rhodamine B (RhB) degradation under UV-A irradiation, based on two developed mathematical models. Thirty hydrothermal syntheses of CaTiO3 were carried out according to the Box-Behnken design, consid-ering synthesis temperature (X1), duration (X2), and concentration of shaping agent (X3) as input variables for two different Ca2+ sources: Ca(NO3)2 and CaCl2 (X4). The conversion of the studied pollutant after 4 h was situated in the range of 20-80%. Second-order regression and feedforward backpropagation artificial neural network models were developed, considering the synthesis con-ditions (X1, X2, X3, X4) as input and the conversion as output variables. The proposed model-based methodology for the optimization of CaTiO3 photocatalytic efficiency finally directed to the ex-perimentally attained value of 96% for 200 degrees C (X1, opt), 23.17 h (X2, opt), 0.67 M (X3, opt), CaCl2 (X4, opt). Furthermore, in the second part of the study, the morphological, structural, textural, and optical properties of selected CaTiO3 samples were investigated via scanning electron mi-croscopy, X-ray diffractometry, N2 sorption, and diffuse reflectance spectroscopy. Finally, the ki-netic parameters for adsorption (kads: 0.10-0.67 m center dot h-1), desorption (kdes: 79-150 mmol center dot m-2 center dot h-1), degradation (kdegr: 0.001-0.010 mmol center dot m-2(1-alpha)center dot W-alpha center dot h-1), and intensity exponent (alpha: 0.54-0.55) were fitted using an optimization procedure, considering the experimentally determined and model-predicted apparent reaction rate constants. The obtained kinetic parameters were corre-lated with the specific surface area of the catalysts and the conversion of RhB.

Knowledge of the chemical stability of active pharmaceutical ingredients (APIs) is an important issue in the drug development process. This work describes a methodical approach and a comprehensive protocol for forced photodegradation studies of solid clopidogrel hydrogen sulfate (Clp) under artificial sunlight and indoor irradiation at different relative humidities (RHs) and atmospheres. The results showed that, at low RHs (up to 21%), this API was relatively resistant to simulated sunlight as well as indoor light. However, at higher RHs (between 52% and 100%), more degradation products were formed, and the degradation rate increased with rising RH. The influence of oxygen on the degradation was relatively low, and most degradation reactions proceeded even in humid argon atmosphere. The photodegradation products (DP) were analyzed with two different HPLC systems (LC-UV, LC-UV-MS) and selected impurities were separated by a semi-preparative HPLC and identified by high resolution mass spectrometry (ESI-TOF-MS) and 1H NMR techniques. Based on the obtained results, a light induced degradation pathway could be proposed for Clp in solid state.