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Novel Au nano-particle catalysts immobilized on both titanium(IV)- and alkylthiol-functionalized SBA-15 type ordered mesoporous silicate supports were developed. The bi-functionalized SBA-15 type support could be synthesized by a one-pot method. To the synthesized supports, Au was immobilized by the reaction of the alkylthiol groups on the supports with AuCl4−, following reduction with NaBH4. The immobilized amount and the formed structures and the electronic property of the Au species depended on the loading of alkylthiol. The moderate size (2–3 nm) nano particulate Au sites formed on Ti(0.5)-SBASH(0.5) were negatively charged. The aerobic alcohol oxidation activity of the catalysts depended on the loading of alkylthiol and the structure of the Au nano-particles. The non-thiol-functionalized catalyst (Au/Ti(0.5)-SBASH(0)) composed of the large (5–30 nm) and the higher thiol-loaded catalyst (Au/Ti(0.5)-SBASH(8)) composed of the small cationic Au species were almost inactive. The most active catalyst was Au/Ti(0.5)-SBASH(0.5) composed of the electron-rich Au nano-particles formed by the electron donation from the highly dispersed thiol groups. Styrene oxidation activity in the presence of 1-phenylethanol with O2 depended on the loadings of titanium(IV) on the Au/Ti(x)-SBASH(0.5). The titanium(IV) sites trapped the H2O2 generated through the alcohol oxidation reaction, and also contributed to the alkene oxidation by activating the trapped H2O2. [ABSTRACT FROM AUTHOR]

Community drinking water sources are increasingly contaminated by various point and non-point sources, with emerging organic contaminants and microbial strains posing health risks and disrupting ecosystems. This study explores the use of zinc oxide nanoparticles (ZnO-NPs) as a non-specific agent to address groundwater contamination and combat microbial resistance effectively. The ZnO-NPs were synthesized via a green chemistry approach, employing a sol-gel method with lemon peel aqueous extract. The catalyst was characterized using techniques including XRD, ATR-FTIR, SEM-EDAX, UV-DRS, BET, and Raman spectroscopy. ZnO-NPs were then tested for photodegradation of quinoline yellow dye (QY) under sunlight irradiation, as well as for their antibacterial and antioxidant properties. The ZnO-NP photocatalyst showed significant photoactivity, attributed to effective separation of photogenerated charge carriers. The efficiency of sunlight dye photodegradation was influenced by catalyst dosage (0.1–0.6 mg L−1), pH (3–11), and initial QY concentration (10–50 mg L−1). The study developed a first-order kinetic model for ZnO-NPs using the Langmuir–Hinshelwood equation, yielding kinetic constants of equilibrium adsorption and photodegradation of Kc = 6.632 × 10−2 L mg−1 and kH = 7.104 × 10−2 mg L−1 min−1, respectively. The results showed that ZnO-NPs were effective against Gram-positive bacterial strains and showed moderate antioxidant activity, suggesting their potential in wastewater disinfection to achieve sustainable development goals. A potential antibacterial mechanism of ZnO-NPs involving interactions with microbial cells is proposed. Additionally, Gaussian Process Regression (GPR) combined with an improved Lévy flight distribution (FDB-LFD) algorithm was used to model QY photodegradation by ZnO-NPs. The ARD-Exponential kernel function provided high accuracy, validated through residue analysis. Finally, an innovative MATLAB-based application was developed to integrate the GPR_FDB-LFD model and FDB-LFD algorithm, streamlining optimization for precise photodegradation rate predictions. The results obtained in this study show that the GPR and FDB-LFD approaches offer efficient and cost-effective methods for predicting dye photodegradation, saving both time and resources. [ABSTRACT FROM AUTHOR]

Nano metal oxides (NMOs), with their unique physico-chemical properties and low toxicity, have become a focus of research in heterogeneous catalysis. Their distinct characteristics, which can be tailored based on size and structure, make them highly efficient catalysts. NMOs have the potential to significantly contribute to the degradation of numerous environmental pollutants through photolytic decomposition. This work comprehensively analyzes the synthesis, catalytic performance, and applications of photocatalytically active metal oxides, specifically titanium, zinc, copper, iron, silver, tin, and tungsten oxides. The primary objective is to demonstrate how the effectiveness of photocatalytic processes can be enhanced and optimized by incorporating metals, non-metals, and metalloids into their structure and forming heterostructures. Furthermore, the aim is to understand the underlying process of photocatalytic oxidation thoroughly. Photocatalysis, a promising approach in advanced oxidation processes, has garnered significant interest in these fields. [ABSTRACT FROM AUTHOR]

Telomere shortening and the induction of senescence and/or cell death may result from inhibition of telomerase activity in cancer cells. Herein, the properties of carbazole–triazole compounds targeting telomerase in human breast cancer cells are explored. All derivatives were evaluated for loss of viability in MCF-7 breast cancer cells, with compound 5g identified as the most potent within the examined series. Green synthesis was employed using water, a reusable nano-Fe2O3-catalyzed reaction, and an electrochemical method for the synthesis of tetrahydrocarbazole and triazoles. The crystal data of compound 4 is also reported. Furthermore, in silico analysis predicted that compound 5g may target human telomerase. Molecular docking analysis of compound 5g towards hTERT predicted a binding affinity of −6.74 kcal/mol. In flow cytometry assays, compound 5g promoted apoptosis and cell cycle arrest in the G2-M phase. Finally, compound 5g inhibited the enzymatic activity of telomerase in human breast cancer cells. In conclusion, a green synthesized series of carbazole–triazoles that target telomerase in cancer cells is reported. [ABSTRACT FROM AUTHOR]

Metal–Organic Frameworks (MOFs) can be a good alternative to conventional catalysts because they are non-toxic and can be selective without compromising efficiency. Nano MOFs such as UiO-66 have proven themselves to be competitive in the catalytic family. In this study, we report the excellent catalytic behavior of UiO-66 MOF in the reduction of a model reaction: 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) over MOF-5 (Zn-BDC) and MIL-101 (Fe-BDC). Nano UiO-66 crystals were synthesized by a hydrothermal process and characterized by Powder X-ray Diffraction, Diffused Reflectance UV-Vis spectroscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. The catalysts' performance during the hydrogenation reduction reaction from 4-NP to 4-AP was investigated in the presence of a reducer, NaBH4. The UiO-66 nano crystals exhibited excellent catalytic behavior owing to its large surface area and Lewis acidic nature at the metal nodes. Furthermore, UiO-66 showed excellent recyclability behavior, verified during repeated consecutive use in a sequence. The catalyst yielded similar catalytic behavior during the reduction of nitrophenols at each cycle, which is a novel finding. [ABSTRACT FROM AUTHOR]

Sillenite materials have been the focus of intense research in recent years due to their unique properties and distinct structure with the I23 space group. This electronic structure has reflected high-quality applications and results for some environmental processes such as photocatalysis. This paper investigates the synthesis of a new sillenite, Bi12SnO20, and its characteristics, emphasizing its potential for photocatalytic applications. The sillenite Bi12SnO20 has been synthesized through the co-precipitation method by mixing the appropriate ratio of Bi and Sn ions. The obtained particles after precipitation and drying were characterized by thermogravimetric analysis (TGA) and then calcined at different temperatures based on this analysis. The phase has been identified by structural analysis using X-ray diffraction (XRD), and its morphology after identification was carried out by scanning electron microscopy (SEM). The calcination temperature has been found to have a critical role in obtaining the phase, where the phase was found to be formed at temperatures between 310 and 400 °C and changed to other phases within higher temperatures. The physicochemical properties of this sillenite were also studied by Fourier-transform infrared spectroscopy (FTIR) and UV Visible Spectrometer (UV-Vis). To study the obtained phases at different calcination temperatures, performance testing was performed under visible light to remove different contaminants, which are Tetracycline, Bisphenol A, and Rhodamine B. The phase Bi12SnO20 obtained at 350 °C with a catalyst dose of 1 g/L showed the highest performance for removing these pollutants with concentrations of 20 mg/L, with an efficiency of almost 100% within 2 h. This work will be useful as an important resource and strategy for the development of this sillenite material in its pure phase. [ABSTRACT FROM AUTHOR]

In response to the increasing global demand for sustainable energy alternatives, this research explores the efficient conversion of sugarcane bagasse to bio-oil through hydrothermal liquefaction (HTL) processes with modified Zeolite Socony Mobil-5 catalysts (ZSM-5). The study systematically investigates the impact of feedstock quantity, reaction temperature, duration, and catalyst loading on bio-oil yield and quality. Optimisation experiments revealed that a feedstock amount of 10 grammes, an HTL temperature of 340 °C for 60 min and a ZSM-5 catalyst loading of 3 grammes resulted in the highest bio-oil yield. Furthermore, the introduction of Ni and Fe metals to ZSM-5 exhibited enhanced catalytic activity without compromising the structure of the zeolites. Comprehensive characterisation of modified catalysts using SEM-EDS, XRD, TGA, TEM, and FTIR provided insight into their structural and chemical properties. The successful incorporation of Ni and Fe into ZSM-5 was confirmed, highlighting promising applications in hydrothermal liquefaction. Gas chromatography–mass spectrometry (GC-MS) analysis of bio-oils demonstrated the effectiveness of the 2% Fe/ZSM-5 catalyst, highlighting a significant increase in hydrocarbon content. FTIR analysis of the produced bio-oils indicated a reduction in functional groups and intensified aromatic peaks, suggesting a shift in chemical composition favouring aromatic hydrocarbons. This study provides valuable information on HTL optimisation, catalyst modification, and bio-oil characterisation, advancing the understanding of sustainable biofuel production. The findings underscore the catalytic prowess of modified ZSM-5, particularly with iron incorporation, in promoting the formation of valuable hydrocarbons during hydrothermal liquefaction. [ABSTRACT FROM AUTHOR]

The bulk and surface properties of materials based on nickel and aluminum oxides and hydroxides, as such or after reduction processes, are reviewed and discussed critically. The actual and potential industrial applications of these materials, both in reducing conditions and in oxidizing conditions, are summarized. Mechanisms for reactant molecule activation are also discussed. [ABSTRACT FROM AUTHOR]

This work developed new electrocatalysts for direct alcohol oxidation fuel cells (DAFCs) by using graphene and reduced graphene oxides (GO and rGO) as supporting nanomaterials for copper–nickel (CuNi) nanocomposites. The manufacture of CuNi, CuNi-GO, and CuNi-rGO nanocomposites was realized through the adaptation of Hummer's method and hydrothermal techniques, with subsequent analysis using a range of analytical tools. The electrocatalytic behavior of these materials in DAFCs, with methanol and ethanol as the fuels, was scrutinized through various methods, including cyclic voltammetry, linear sweep, chronoamperometry, and electrochemical impedance spectroscopy. This investigation also assessed the stability and charge transfer dynamics. The rGO-based CuNi nanocomposite demonstrated a remarkable performance boost, showing increases of approximately 319.6% for methanol and 252.6% for ethanol oxidation compared to bare CuNi. The integration of silver nanoparticles into the Ag-CuNi-rGO electrode led to a current density surge to 679.3 mA/g, which signifies enhancements of 254.2% and 812.6% relative to the CuNi-rGO and CuNi electrodes, respectively. These enhancements are ascribed to the augmented densities of hot sites and the synergistic interactions within the nanocatalysts. The findings underscore the potential of Ag and rGO as effective supports for CuNi nanocomposites, amplifying their catalytic efficiency in DAFC applications. [ABSTRACT FROM AUTHOR]

To promote environmental development and sustain resource circularity, recycling metals from electronic waste is essential. Electronic waste is a significant secondary source of metals, with its production increasing rapidly and most remaining unrecycled. In solar panels, copper is the second-most-valuable metal after silver. We propose an innovative method to recycle copper from waste solar panels and convert it into copper oxide nanoparticles (CuONPs) using a green synthesis method. Synthesizing CuONPs is advantageous due to their large surface area compared to bulk material. Nitric acid, a strong oxidizing agent, was used to leach copper from solid copper wires in waste solar panels. A green synthesis method, following a bottom-up approach, was employed using Piper nigrum fruit extract to synthesize CuONPs. The synthesized nanoparticles were characterized using various qualitative and quantitative techniques. Spectroscopic analysis confirmed the formation of CuONPs, and transmission electron microscopy revealed that the nanoparticles were spherical with sizes up to 60 nm. Biomolecules from the Piper nigrum extract were detected on the surface of the crystalline CuONPs. These nanoparticles exhibited antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus using a well-diffusion method, showing a larger zone of inhibition for E. coli compared to S. aureus. This research demonstrates the complete recovery of copper from waste solar panels and its conversion into useful CuONPs, which have potential medicinal applications. [ABSTRACT FROM AUTHOR]

This review article provides useful information on TiO2 and ZnO photocatalysts and their derivatives in removing organic contaminants such as dyes, hydrocarbons, pesticides, etc. Also, the reaction mechanisms of TiO2 and ZnO photocatalysts and their derivatives were investigated. In addition, the impact of adding metallic (e.g., Ag, Co, Pt, Pd, Cu, Au, and Ni) and non-metallic (e.g., C, N, O, and S) cocatalysts to their structure on the photodegradation efficiency of organic compounds was thoroughly studied. Moreover, the advantages and disadvantages of various synthesis procedures of ZnO and TiO2 nanocatalysts were discussed and compared. Furthermore, the impact of photocatalyst dosage, photocatalyst structure, contaminant concentration, pH, light intensity and wavelength, temperature, and reaction time on the photodegradation efficiency were studied. According to previous studies, adding metallic and non-metallic cocatalysts to the TiO2 and ZnO structure led to a remarkable enhancement in their stability and reusability. In addition, metallic and non-metallic cocatalysts attached to TiO2 and ZnO demonstrated remarkable photocatalytic efficiency in removing organic contaminants. [ABSTRACT FROM AUTHOR]

The TiO2-Eu and TiO2-La systems were successfully synthesized using the microwave method. Based on the results of X-ray diffraction analysis, it was found that regardless of the analyzed systems, two crystal structures were noted for the obtained samples: anatase and rutile. The analysis, such as XPS and EDS, proved that the doped lanthanum and europium nano-particles are present only on the TiO2 surface without disturbing the crystal lattice. In the synthesized systems, there were no significant changes in the bandgap energy. Moreover, all the obtained systems were characterized by high thermal stability. One of the key objectives of the work, and a scientific novelty, was the introduction of UV-LED lamps into the metronidazole photo-oxidation pathway. The results of the photo-oxidation study showed that the obtained TiO2 systems doped with selected lanthanides (Eu or La) show high efficiency in the removal of metronidazole, and at the same consuming nearly 10 times less electricity compared to conventional UV lamps (high-pressure mercury lamp). Liquid-chromatography mass-spectrometry (LC-MS) analysis of an intermediate solution showed the presence of fragments of the degraded molecule by m/z 114, 83, and 60, prompting the formulation of a plausible photodegradation pathway for metronidazole. [ABSTRACT FROM AUTHOR]

In this study, graphene quantum dots (GQDs) have been incorporated into the g-C3N4/ZIF-67 heterojunction system as a photosensitizer to enhance photocatalytic conversion of CO2-to-CO. The GQDs are deposited onto the surface of g-C3N4/ZIF-67 using a simple water bath procedure. As expected, GQDs/g-C3N4/ZIF-67 presents outstanding performance in CO2 photoreduction. Among the GQDs/g-C3N4/ZIF-67 ternary photocatalysts, 7 GQDs-CN/ZIF-67 exhibits the best photocatalytic CO2 reduction ability with a CO yield of 51.71 μmol g−1, which is 5.05 and 1.87 times more than pristine g-C3N4 (10.24 μmol g−1) and g-C3N4/ZIF-67 (27.65 μmol g−1), respectively. This result shows that upon combination of GQDs with ZIF-67/g-C3N4, GQDs can be used as photosensitizers to improve the optical absorption capacity of the photocatalyst. Furthermore, GQDs serve as electron channels, facilitating the transport of photo-induced electrons from ZIF-67 to g-C3N4, which promotes photogenerated carrier separation efficiency. This study innovatively adds GQDs to the heterojunction and applies the prepared ternary composite to the CO2 photoreduction, which inspires a novel direction for the design of non-noble metal photocatalysts. [ABSTRACT FROM AUTHOR]

Semi-hydrogenation of acetylene to ethylene over metal oxide-supported Au nanoparticles is an interesting topic. Here, a hydrotalcite-based MMgAlOx (M=Cu, Ni, and Co) composite oxide was exploited by introducing different Cu, Ni, and Co dopants with unique properties, and then used as support to obtain Au/MMgAlOx catalysts via a modified deposition–precipitation method. XRD, BET, ICP-OES, TEM, Raman, XPS, and TPD were employed to investigate their physic-chemical properties and catalytic performances for the semi-hydrogenation of acetylene to ethylene. Generally, the catalytic activity of the Cu-modified Au/CuMgAlOx catalyst was higher than that of the other modified catalysts. The TOR for Au/CuMgAlOx was 0.0598 h−1, which was 30 times higher than that of Au/MgAl2O4. The SEM and XRD results showed no significant difference in structure or morphology after introducing the dopants. These dopants had an unfavorable effect on the Au particle size, as confirmed by the TEM studies. Accordingly, the effects on catalytic performance of the M dopant of the obtained Au/MMgAlOx catalyst were improved. Results of Raman, NH3-TPD, and CO2-TPD confirmed that the Au/CuMgAlOx catalyst had more basic sites, which is beneficial for less coking on the catalyst surface after the reaction. XPS analysis showed that gold nanoparticles exhibited a partially oxidized state at the edges and surfaces of CuMgAlOx. Besides an increased proportion of basic sites on Au/CuMgAlOx catalysts, the charge transfer from nanogold to the Cu-doped matrix support probably played a positive role in the selective hydrogenation of acetylene. The stability and deactivation of Au/CuMgAlOx catalysts were also discussed and a possible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article on the removal of emerging organic pollutants in drinking water and watershed water using zeolite mineral composite photocatalysts. The correction involves fixing citation numbers for references throughout the manuscript. The corrected references cover topics such as photocatalysis, wastewater treatment, heavy metal removal, and pollutant degradation. The document is a compilation of research articles and reviews on zeolites and their applications in environmental remediation, catalysis, and adsorption. The articles discuss the synthesis, characterization, and photocatalytic activity of zeolite-based materials, as well as their use in removing heavy metals and organic pollutants from water. The research highlights the potential of zeolites as efficient and sustainable materials for environmental applications. Additionally, the document includes a collection of scientific articles focusing on the use of clinoptilolite zeolite as a photocatalyst for degrading organic pollutants in wastewater. The articles explore the photocatalytic activity of different catalysts supported on clinoptilolite nanoparticles and investigate the degradation of various organic compounds. The studies demonstrate the potential of these photocatalysts for removing organic pollutants from wastewater and advancing water treatment technologies. Furthermore, the document provides a list of scientific articles discussing the photocatalytic degradation of pollutants like antibiotics, herbicides, dyes, and other organic compounds. The articles examine different photocatalysts and their effectiveness under simulated solar or visible light. They also discuss the use of materials like zeolite, titanium dioxide, [Extracted from the article]

The global issue for proton exchange membrane fuel cell market development is a reduction in the device cost through an increase in efficiency of the oxygen reduction reaction occurring at the cathode and an extension of the service life of the electrochemical device. Losses in the fuel cell performance are due to various degradation mechanisms in the catalytic layers taking place under conditions of high electric potential, temperature, and humidity. This review is devoted to recent advances in the field of increasing the efficiency and durability of electrocatalysts and other electrode materials by introducing structured carbon components into their composition. The main synthesis methods, physicochemical and electrochemical properties of materials, and performance of devices on their basis are presented. The main correlations between the composition and properties of structured carbon electrode materials, which can provide successful solutions to the highlighted issues, are revealed. [ABSTRACT FROM AUTHOR]

One of the most challenging problems for people around the world is the lack of clean water. In the past few decades, the massive discharge of emerging organic pollutants (EOPs) into natural water bodies has exacerbated this crisis. Considerable research efforts have been devoted to removing these EOPs due to their biotoxicity at low concentrations. Heterogeneous photocatalysis via coupling clay minerals with nanostructured semiconductors has proven to be an economical, efficient, and environmentally friendly technology for the elimination of EOPs in drinking water and watershed water. Natural zeolite minerals (especially clinoptilolites) are regarded as appropriate supports for semiconductor-based photocatalysts due to their characteristics of having a low cost, environmental friendliness, easy availability, co-catalysis, etc. This review summarizes the latest research on clinoptilolites used as supports to prepare binary and ternary metal oxide or sulfide semiconductor-based hybrid photocatalysts. Various preparation methods of the composite photocatalysts and their degradation efficiencies for the target contaminants are introduced. It is found that the good catalytic activity of the composite photocatalyst could be attributed to the synergistic effect of combining the clinoptilolite adsorbent with the semiconductor catalyst in the heterogeneous system, which could endow the composites with an excellent adsorption capacity and produce more e−/h+ pairs under suitable light irradiation. Finally, we highlight the serious threat of EOPs to the ecological environment and propose the current challenges and limitations, before putting the zeolite mineral composite photocatalysts into practice. The present work would provide a theoretical basis and scientific support for the application of zeolite-based photocatalysts for degrading EOPs. [ABSTRACT FROM AUTHOR]

In this study, the optical properties of a TiO2 photocatalyst were enhanced with various impregnations of Er3+ and Ni2+ separately, using the impregnation method as photocatalysts for the direct solar photolysis degradation of chloroxylenol. The synthesized Er3+/TiO2 and Ni2+/TiO2 catalysts were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), metal mapping, and ultraviolet visible (UV–Vis) spectroscopy. The results showed that the Er3+/TiO2 and Ni2+/TiO2 nano-particles have the same structures of TiO2 nano-particles with little difference in particle size. The Er3+ and Ni2+ ions were well-distributed on the TiO2 surface, and it was found that the maximum band gap decreased from 3.13 eV for intrinsic TiO2 to 2.63 eV at 1.8 wt % Er3+/TiO2 and to 2.47 eV at 0.6 wt % for Ni2+/TiO2. The initial concentration of chloroxylenol, catalyst loading, and pH of the solution are the most important factors affecting the solar photocatalytic degradation efficiency that were optimized using Design Expert software (version 6.0.10, Minneapolis, MN, USA, 2003). The results showed that the optimal conditions for chloroxylenol degradation include a pH of 4, TiO2 loading at 3 g/L, and a chloroxylenol concentration of 50 mg/L. These conditions resulted in a degradation efficiency of 90.40% after 60 min of direct solar irradiation, wherein the solar energy recorded during a clear sunny day is 1000 W/m2. However, some experiments were conducted on a semi-cloudy day to cover all weather stated and to study the degradation kinetics. During semi-cloudy day experiments, using Er3+/TiO2 and Ni2+/TiO2 with a solar irradiation activity of 600 W/m2 for a 60 min exposure at optimal conditions increased the degradation efficiency from 68.28% for intrinsic TiO2 to 82.38% for Er3+/TiO2 and 80.70% for Ni2+/TiO2. [ABSTRACT FROM AUTHOR]

Improper disposal of waste plastic has caused serious ecological and environmental pollution problems. Transforming plastics into high value-added chemicals can not only achieve efficient recycling of waste plastics, but is also an effective way to control white pollution. The catalyst selectively breaks the C–C bond of polyolefin plastic under heat treatment and converts it into liquid fuel, thus realizing sustainable recycling of plastics and has a good development prospect. This review provides a detailed overview of the current development of catalytic pyrolysis, catalytic hydrolysis, solvent decomposition, and supercritical hydrothermal liquefaction for cracking plastics to make fuel oil. The reaction mechanism, influencing factors, and promoting effects of catalysts in various degradation technologies are analyzed and summarized, and the latest proposed tandem reaction for degrading plastics is briefly introduced. Finally, some optimization paths of waste plastic pyrolysis to fuel oil technology are proposed: synergies between mixed raw materials, in-depth exploration of catalysts, design and manufacture of reactors that match the pyrolysis technology. All these are important research directions for promoting the industrialization of plastic pyrolysis to fuel oil. [ABSTRACT FROM AUTHOR]

The catalytic partial oxidation of methane (CPOM) to methanol has been regarded as a promising approach for methane utilization, despite that the conversion remains a formidable challenge in the perspective of catalysts. A novel catalyst system of multi-wall carbon nanotubes (MWCNTs) that supported Fe2O3 with existing I2, consisting of non-noble metal and working in weak acid at an ambient temperature, was investigated for CPOM. MWCNTs supported the Fe2O3 catalyst, which was prepared by the impregnation method and characterized via HRTEM, XRD, XPS, FT-IR, and BET techniques. The characterization results reveal that, as a non-noble metal catalyst, the Fe2O3/MWCNTs catalyst had a good catalytic performance and stability in the CPOM. With the variation of reaction pressure and the dosage of Fe2O3/MWCNTs, the catalyst system obtained the highest methane conversion rate of 7.41% and methanol selectivity of 86.3%, which is analogous to that of the equivalently strong acid catalyst system. The I2-Fe2O3/MWCNTs catalyst system has great potential in the application of CPOM under mild, environmentally benign conditions, such as non-noble metal requirement, ambient temperature, and weak acid. The reaction mechanism was discussed. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole (SMX) is a common antibiotic that is considered an emerging pollutant of water bodies, as it is toxic for various aquatic species. TiO2-based photocatalysis is a promising method for SMX degradation in water. In this work, TiO2/zeolite (Z-45 loaded with TiO2 labeled as TZ and ZSM-5 loaded with TiO2 labeled as TZSM) composites were prepared by mechanical mixing and liquid impregnation methods, and the photocatalytic performance of these composites (200 mg·L−1) was investigated toward the degradation of SMX (30 mg·L−1) in water under UV light (365 nm). The pseudo-first-order reaction rate constant of the TZSM1450 composite was 0.501 min−1, which was 2.08 times higher than that of TiO2 (k = 0.241 min−1). Complete SMX degradation was observed in 10 min using the UV/TZSM1450 system. The mineralization ability in terms of total organic carbon (TOC) removal was also assessed for all of the prepared composites. The results showed that 65% and 67% of SMX could be mineralized within 120 min of photocatalytic reaction by TZSM2600 and TZSM1450, respectively. The presence of Cl − and CO 3 2 − anions inhibited the degradation of SMX, while the presence of NO 3 − had almost no effect on the degradation efficiency of the UV/TZSM1450 system. The electrical energy per order estimated for the prepared composites was in the range of 68.53–946.48 kWh m−3 order−1. The results obtained revealed that the TZSM1450 composite shows promising potential as a photocatalyst for both the degradation and mineralization of SMX. [ABSTRACT FROM AUTHOR]

To develop customized sulfur–resistant catalysts for the water gas shift (WGS) reaction in the waste–to–hydrogen process, the effects of changing the nucleation conditions of the CeO2 support on catalytic performance were investigated. Supersaturation is a critical kinetic parameter for nuclei formation. The degree of supersaturation of the CeO2 precipitation solution was controlled by varying the cerium precursor concentration from 0.02 to 0.20 M. Next, 2 wt.% of Pt was impregnated on those various CeO2 supports by the incipient wetness impregnation method. The prepared samples were then evaluated in a WGS reaction using waste–derived synthesis gas containing 500 ppm H2S. The Pt catalyst supported by CeO2 prepared at the highest precursor concentration of 0.20 M exhibited the best sulfur resistance and catalytic activity regeneration. The sulfur tolerance of the catalyst demonstrated a close correlation with its oxygen storage capacity and easier reducibility. The formation of oxygen vacancies in CeO2 supports is promoted by the formation of small crystals due to a high degree of supersaturation. [ABSTRACT FROM AUTHOR]

Zr-modified LaNiO3 catalysts (LaNixZr1−xO3; 0 ≤ x ≤ 1) are synthesized by the sol–gel method. The physio-chemical properties of materials are investigated using different characterization techniques and evaluated for the CO2 reforming of methane to syngas. Interestingly, the characterization studies revealed the phase transformation from La-Zr pyrochlore to La-Ni perovskite depending on the Ni:Zr ratio in the material. The formation of the pyrochlore phase is observed for high-Zr-containing catalysts, thus leading to the production of bulk NiO. The formation of La-Ni perovskite is observed for high-Ni-containing catalysts and the ZrO2 acted as a support. The formation of La-Ni perovskite supported on ZrO2 enhanced the Ni dispersion of the catalysts. The high dispersion of Ni enhanced the catalytic activity, and LaNi0.8Zr0.2O3 showed the best performance among all of the studied catalysts in terms of conversions and the H2/CO ratio. [ABSTRACT FROM AUTHOR]

This innovative article provides a detailed description of the successful biosynthesis of zinc nanoparticles (ZnO-NPs) using an aqueous extract of Algerian Date Syrup, also known as molasses. A meticulous process was carried out to determine the optimal calcination temperature for ZnO-NPs, a crucial step in the preparation of these nanoparticles. The study was further extended by creating ZnO/rGOx nanocomposites through a hydrothermal method, varying the concentrations of reduced graphene oxide (rGO) at 5%, 10%, and 15%. The characteristics of the nanocomposites were thoroughly explored, encompassing chemical, optical, and morphological aspects, using sophisticated analysis techniques such as scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV DRS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). These analyses provided an in-depth understanding of the structure and properties of the nanocomposites. The centerpiece of this study is the evaluation of the photocatalytic degradation capacity of ZnO-NPs and ZnO/rGOx nanocomposites. These materials have demonstrated their ability to act as cost-effective and environmentally friendly photocatalysts for wastewater treatment. Experiments on methylene blue degradation under UV irradiation were conducted, yielding impressive results: a degradation efficiency of 86.6% was achieved in 140 min using 1 g/L of ZnO-NPs, and this rate reached 100% with the ZnO/rGO catalyst in the same time frame, highlighting its superiority as a photocatalyst. Furthermore, this study examined the variables affecting the photocatalysis experiment, including the solution's pH and the amount of catalyst. The results revealed that the ZnO/rGO photocatalyst reached its optimal efficiency under neutral pH conditions and at a concentration of 1 g/L, providing crucial information for practical use of these materials. This enriched article highlights the promising potential of ZnO-NPs and ZnO/rGOx nanocomposites as efficient photocatalysts for methylene blue degradation, paving the way for significant environmental applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

Series of ceria-zirconia (CZ)-based nano-materials with a d50 in the range of 0.2 to 1.3 microns were made using the jar milling, Eiger milling, and steam jet milling (SJM) techniques. The effect of the milling conditions on the morphology and textural properties was studied. High-energy steam jet milling in a quasi-hydrothermal environment (with potential local temperature spikes over 500 °C) significantly impacted the CZ crystal structure by inducing lattice distortions. It was shown that the acquired lattice stress resulted in a significant increase in oxygen mobility, which was manifested by a TPR-H2 Tmax shift from 450–550 to 150–250 °C. CZ materials with fast oxygen mobility are metastable phases, and re-slurring nano-CZ powders in water and impregnation with precious metals had stabilizing effects on fast oxygen mobility. Efficiently enhancing the CZ redox activity milling process took place in the following order: Steam jet milling > Eiger milling > jar milling. [ABSTRACT FROM AUTHOR]

TiO2 nanotubes are a prominent type of TiO2-based nanostructure compared to nanorod arrays. A promising way to improve photocatalytic performance is modifying TiO2 nanotubes with metals, either on the surface or inside the tubes. There is a substantial demand for enhancing the conductivity and charge separation of TiO2 nanotubes, with a major focus on gold (Au) modification. Gold (Au) coatings have significantly improved the photocatalytic activity of TiO2 nanotubes, particularly in pollutant oxidation. However, the mechanism underlying the action of Au-modified TiO2 nanotubes in photocatalytic nitrobenzene oxidation under electrochemical induction remains unclear. Therefore, we conducted related experiments to explore the optimal Au concentration under various conditions. Under electric field induction, the maximum removal rate achieved was 54.9%. Lastly, we analyzed the relevant photocatalytic mechanism to elucidate the responses of electrons and holes to a simulated contaminant under a photo-electrochemical field. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated the role of synthesized selenium nanoparticles from Spirulina platensis extract (SP-SeNPs) on Pacific whiteleg shrimps' (Litopenaeus vannamei) growth performance, as well as the potential role in alleviating the negative impacts of cadmium (Cd) toxicity. Based on the detected growth performance parameters, digestive enzyme activities, and biochemical components of shrimps after 56 days of the experiment, SP-SeNPs at 0.5 mg/kg were recommended. Moreover, the antioxidative status and histological investigation of shrimp tissues after exposure to Cd for 10 days indicated that SP-SeNPs could mitigate the pathological alternations induced with Cd toxicity. The findings of this study highlight the utility of nanotechnology for the enhanced production of Pacific white shrimps which could be utilized as one of the main sources for the animal proteins needed for human consumption. Shrimp culture is quite important and popular across the world. This study aimed to evaluate the growth-promoting potential of synthesized selenium nanoparticles from Spirulina platensis extract (SP-SeNPs) as a food source for Pacific whiteleg shrimp (Litopenaeus vannamei). However, pollution is considered a significant element affecting shrimp health and development. The effectiveness of SP-SeNPs in alleviating the negative effects of cadmium toxicity was also evaluated. Firstly, the shrimps (about 120 individuals with 6.0 ± 0.12 g of initial weight) were divided randomly into four groups in triplicates (30 shrimps/ treatment). The control group (SP-SeNPs—0 mg/kg diet) and three treatments were fed dietary SP-SeNPs (0.250, 0.50, and 1.0 mg/kg diet) for 56 days. Growth performance, digestive enzymes activities (protease, amylase, and lipase), and other biochemical components (total protein, lipid, amino acids, and carbohydrate) were evaluated. After 56 days of growth, another 150 adult shrimps were used under laboratory conditions to determine median lethal concentration of cadmium (96 h LC50), and 30 individuals were treated with cadmium (1/2 of LC50, 0.2 mg L−1) for 10 days only. Tissue samples were collected for measuring catalase (CAT), total antioxidant capacity (TAC), superoxide dismutase (SOD), malondialdehyde (MDA) levels, cadmium bioaccumulation, and histopathological investigation. The results illustrated that the application of SP-SeNPs as feed additives at varying levels significantly improved growth performance (high weight gain, specific growth rate, and low feed conversion rates) relative to the control group. Furthermore, dietary SP-SeNPs enhanced digestive enzyme activities and the concentrations of biochemical components more than the control group. Upon concurrent exposure to cadmium, the antioxidative status was significantly enhanced, and histopathological alterations were mitigated. In conclusion, this study recommended supplementation of SP-SeNPs at 0.50 mg/kg diet to enhance optimal growth rate, digestive enzyme activities, levels of antioxidants in Litopenaeus vannamei, and mitigate the pathological alternations induced with Cd toxicity. [ABSTRACT FROM AUTHOR]

We used a new one-pot green technique to prepare polysaccharide-based Pd and PdAg nanocatalysts. Catalysts were obtained using a sequentially supporting natural polymer (2-hydroxyethyl cellulose (HEC), chitosan (Chit), pectin (Pec)) and metals on zinc oxide. Nanocatalysts based on a polysaccharide were studied using various physicochemical methods (IR spectroscopy, transmission electron microscopy, X-ray powder diffraction, etc.). The catalyst characterization results indicated the complete adsorption of polysaccharides and metal ions onto the inorganic support (ZnO). We demonstrated the formation of polysaccharide-stabilized Pd nanoparticles with a size of ~2 nm. Metal nanoparticles were uniformly located on the surface of polysaccharide-modified zinc oxide. The synthesized catalysts were tested using liquid-phase hydrogenation of 2-hexyn-1-ol under mild conditions (0.1 MPa, 40 °C). Close conversion values of 2-hexyn1-ol were obtained for all the developed catalysts. The selectivity for cis-hexen-1-ol of the polysaccharide-based PdAg nanocatalysts varied as follows: PdAg-HEC/ZnO > PdAg-Pec/ZnO > PdAg-Chit/ZnO. A similar correlation was obtained in the presence of monometallic Pd-polysaccharide/ZnO catalysts. We determined the optimum reaction temperature and catalyst loading for PdAg catalysts modified using HEC and Chit (40 °C, 0.05 g). [ABSTRACT FROM AUTHOR]

Nitrogen-containing aromatic polymers such as polyimide are known for their high thermal stability. While they have been widely used in industry, their relevance to catalysis is still quite limited. In recent years, nitrogen-containing polymers have been explored as precursors of nitrogen-doped carbonaceous materials, which are particularly attractive as non-precious metal catalysts for oxygen reduction in fuel cells. The high thermal stability of nitrogen-containing polymers contributes to an effective control over the morphology of the resulting carbonaceous catalysts. This review article provides an overview of the recent progress on the research and development of Fe/N/C oxygen reduction catalysts prepared from morphology-controlled nitrogen-containing polymers. [ABSTRACT FROM AUTHOR]

This multi-disciplinary paper aims to provide a roadmap for the development of an integrated, process-intensified technology for the production of H2, NH3 and NH3-based symbiotic/smart fertilizers (referred to as target products) from renewable feedstock with CO2 sequestration and utilization while addressing environmental issues relating to the emerging Food, Energy and Water shortages as a result of global warming. The paper also discloses several novel processes, reactors and catalysts. In addition to the process intensification character of the processes used and reactors designed in this study, they also deliver novel or superior products so as to lower both capital and processing costs. The critical elements of the proposed technology in the sustainable production of the target products are examined under three-sections: (1) Materials: They include natural or synthetic porous water absorbents for NH3 sequestration and symbiotic and smart fertilizers (S-fertilizers), synthesis of plasma interactive supported catalysts including supported piezoelectric catalysts, supported high-entropy catalysts, plasma generating-chemical looping and natural catalysts and catalysts based on quantum effects in plasma. Their performance in NH3 synthesis and CO2 conversion to CO as well as the direct conversion of syngas to NH3 and NH3—fertilizers are evaluated, and their mechanisms investigated. The plasma-generating chemical-looping catalysts (Catalysts, 2020, 10, 152; and 2016, 6, 80) were further modified to obtain a highly active piezoelectric catalyst with high levels of chemical and morphological heterogeneity. In particular, the mechanism of structure formation in the catalysts BaTi1−rMrO3−x−y{#}xNz and M3O4−x−y{#}xNz/Si = X was studied. Here, z = 2y/3, {#} represents an oxygen vacancy and M is a transition metal catalyst. (2) Intensified processes: They include, multi-oxidant (air, oxygen, CO2 and water) fueled catalytic biomass/waste gasification for the generation of hydrogen-enriched syngas (H2, CO, CO2, CH4, N2); plasma enhanced syngas cleaning with ca. 99% tar removal; direct syngas-to-NH3 based fertilizer conversion using catalytic plasma with CO2 sequestration and microwave energized packed bed flow reactors with in situ reactive separation; CO2 conversion to CO with BaTiO3−x{#}x or biochar to achieve in situ O2 sequestration leading to higher CO2 conversion, biochar upgrading for agricultural applications; NH3 sequestration with CO2 and urea synthesis. (3) Reactors: Several patented process-intensified novel reactors were described and utilized. They are all based on the Multi-Reaction Zone Reactor (M-RZR) concept and include, a multi-oxidant gasifier, syngas cleaning reactor, NH3 and fertilizer production reactors with in situ NH3 sequestration with mineral acids or CO2. The approach adopted for the design of the critical reactors is to use the critical materials (including natural catalysts and soil additives) in order to enhance intensified H2 and NH3 production. Ultimately, they become an essential part of the S-fertilizer system, providing efficient fertilizer use and enhanced crop yield, especially under water and nutrient stress. These critical processes and reactors are based on a process intensification philosophy where critical materials are utilized in the acceleration of the reactions including NH3 production and carbon dioxide reduction. When compared with the current NH3 production technology (Haber–Bosch process), the proposed technology achieves higher ammonia conversion at much lower temperatures and atmospheric pressure while eliminating the costly NH3 separation process through in situ reactive separation, which results in the production of S-fertilizers or H2 or urea precursor (ammonium carbamate). As such, the cost of NH3-based S-fertilizers can become competitive with small-scale distributed production platforms compared with the Haber–Bosch fertilizers. [ABSTRACT FROM AUTHOR]

Functionalized polyethylene-based nanocomposites were prepared by in situ polymerization of ethylene with modified or neat MCM-41 nanoparticles (NMCM-41). Two different synthetic approaches were investigated to improve the compatibility between the hydrophobic HDPE matrix and the hydrophilic NMCM-41: (i) incorporation of UA into the polymeric matrix by copolymerization with ethylene, promoted by the zirconocene catalyst under homogeneous conditions, in the presence of pristine NMCM-41; (ii) use of undecenoic acid (UA) as an interfacial agent to obtain decorated NMCM-41 to be used as nanofiller for the in situ ethylene polymerization, catalyzed by Cp2ZrCl2/MAO under supported conditions. The strong polar character of the carboxylic group is expected to either increase the hydrophilicity of the HDPE chains (strategy i) or interact with the NMCM-41 surface and provide an additional link to the polymeric chains via copolymerization of the vinyl group under supported conditions (strategy ii). Although metallocene catalysts have been shown to copolymerize olefins with functional monomers, the presence of oxygen-containing compounds in the reaction media strongly affects the polymerization activity as a result of the interaction of functional groups with the electrophilic active center of the catalyst. Thus, UA was pre-contacted with tri(isobutyl)aluminum (TIBA) prior to its use in the polymerization to reduce the deactivating character of the carboxylic acid groups towards the zirconocene catalyst. The influence of the UA presence on the polymerization behavior of the protection step is discussed, and the polymerization activities observed for the different approaches are compared. In addition, the thermal behavior and structural details of the resulting materials have been characterized. The impact of using neat or functionalized NMCM-41 on the final dispersion within the polymeric matrix is also analyzed, which is correlated with the mechanical performance exhibited by these HDPE_UA_NMCM-41 nanocomposites. [ABSTRACT FROM AUTHOR]

LaMnO3-based perovskites are widely recognized as promising catalysts for several oxidation reactions, but the final physicochemical and catalytic properties can be greatly influenced by the adopted synthesis procedure. In this work, a series of A-site-deficient perovskites of composition La0.8MnO3 and La0.8Mn0.9B0.1O3 (B = Ni, Cu) were prepared through the citrate combustion route with variations in two synthesis parameters: a citric acid/metal cations molar ratio (CA/M) of either 1.1 or 1.5 and either acidic (given by HNO3 + citric acid) or neutral (after NH3 addition) pH of the precursor solution. The obtained samples were characterized by XRD, H2-TPR, O2-TPD, N2 physisorption, SEM-EDX and XPS. Acidic pH coupled with a CA/M ratio of 1.1 clearly emerged superior among all the other combinations of the two parameters, resulting in smaller crystallite size, higher surface area and porosity, enhanced Mn4+ reducibility and the ability to release oxygen species; these features were even further improved by B-site substitution with 10 mol% Ni and Cu cations. The synthesized catalysts were tested in CH4 oxidation to CO2 under stoichiometric O2, confirming the great superiority of samples prepared in acidic pH with a CA/M ratio of 1.1. Ni and Cu doping had a beneficial effect on catalytic activity, which, however, was more evident for less optimized perovskites (acidic pH and CA/M ratio of 1.5), without significance differences among the two dopants. [ABSTRACT FROM AUTHOR]

This review highlights recent research on the application of core–shell structured materials as catalysts in the oxidation of alcohols to value-added products, such as benzaldehyde, acetophenone, benzophenone, cinnamaldehyde, and vanillin, among others. While the application of various unconventional energy inputs (such as microwave and ultrasound irradiation) was reported, this paper focuses on conventional heating. The oxidation of homocyclic aromatic, heterocyclic aromatic, aliphatic, and alicyclic alcohols catalyzed by core–shell composite catalysts is addressed. This work also highlights some unique advantages of core–shell nanomaterial catalysis, namely the flexibility of combining individual functions for specific purposes as well as the effect of various parameters on the catalytic performance of these materials. [ABSTRACT FROM AUTHOR]

Although Fe-based catalysts have made significant progress in Fischer–Tropsch synthesis, the effect of residual sodium on the structural properties and catalytic performance of Fe-based catalysts has been controversial. Herein, we report the positive role of residual sodium in the structural properties and performance of FeAlNa catalysts for olefins synthesis from syngas. Meanwhile, the as-prepared catalysts were characterized by the multiple characterization technique to reveal the positive role of residual sodium on the structural properties. The characterization results revealed that the residual sodium improved the reduction behavior of Fe species and adsorption ability of CO, and inhibited the secondary hydrogenation due to its weak adsorption ability of H2. Moreover, the residual sodium inhibited the interaction between Fe and Al. Importantly, a high olefins/paraffins ratio of 6.19 and low CH4 selectivity of 12.8% were achieved on the residual sodium modified FeAlNa catalyst. An in-depth understanding of the structural properties and catalytic performance of residual sodium on FeAl-based catalysts can provide a theoretical basis for the development of novel efficient catalysts and large-scale applications for olefins synthesis from syngas. [ABSTRACT FROM AUTHOR]

The shortage of water resources has caused extensive research to be conducted in this field to develop effective, rapid, and affordable wastewater treatment methods. For the treatment of wastewater, modern oxidation techniques are desirable due to their excellent performance and simplicity of implementation. In this project, wet impregnation and the hydrothermal technique were applied to synthesize a modified catalyst. Different analysis methods were used to determine its characteristics, including XRD, BET, FT-IR, NH 3 − TPD , and FE-SEM. The catalyst features a spherical shape, large surface area, high crystallinity, and uniform active phase dispersion. In order to eliminate the methylene blue dye as a modeling effluent, the catalyst's performance was examined in a heterogeneous quasi-electro-Fenton (EF) reaction. The impact of various performance characteristics, such as catalyst concentration in the reaction medium, solution pH, and current intensity between the two electrodes, was elucidated. According to the results, the best operational circumstances included a pH level of 2, a catalyst concentration of 0.15 g/L, and a current of 150 mA, resulting in the greatest elimination efficiency of 101%. The catalyst's performance was stable during three consecutive tests. A pseudo-first-order model for the elimination reaction's kinetics was developed, which showed acceptable agreement with the experimental results. This study's findings help clarify how well the heterogeneous zeolite catalyst functions in the pseudo-EF reaction. The results revealed the method's potential to be implemented in wastewater treatment. An artificial neural network model is utilized to predict the removal percentage. The hyperparameter tuning is used to find the best model, and the model achieved an MAE of 1.26% and the R 2 was 0.99. [ABSTRACT FROM AUTHOR]

Titanium-doped zinc ferrite was used as a photo catalyst for breaking down C-C and C-H bonds of methylene blue dye as a model for the decomposition of organic pollutants. Different concentrations of Ti were used to impede into the spinel structure of zinc ferrite by in situ addition during the preparation. Different characterization techniques were used to characterize the prepared materials including the deep analysis of the electronic spectra, which proved the surface modification of ferrite due to the Ti doping. In addition, we make a comparison study of photo degradation using ordinary UV irradiation and commercial LED light irradiation, which gives very promising results. A correlation between the structure and the photo catalytic behavior of the materials is assigned. [ABSTRACT FROM AUTHOR]

Cryogels from noble metal NPs have proven to be highly efficient catalysts due to their high specific surface area which increases the mass transfer channels and catalytic active sites. By using metal oxides as co-catalysts, the costs of the material can be significantly reduced, while the catalytic activity can remain the same or even improve due to synergetic effects. In this work, we synthesize different cryogel thin films supported on modified ITO substrates from Pt, Pd nanoparticles (NPs), and mixtures of these noble metals with γ-Fe2O3 NPs in a very low concentration (1 wt% of the noble metal). Structural and elemental analysis of the samples are performed, along with the measurement and analysis of their catalytic activity. The electrocatalytic activity of the cryogels towards ethanol oxidation reaction (EOR) in alkaline media was evaluated by means of cyclic voltammetry. By mixing γ-Fe2O3 NPs with Pt or Pd NPs in the cryogel structure, we observe increased tolerance against poisonous surface intermediates produced during the EOR. Moreover, we observe an increase in the catalytic activity towards EOR in the case of the 1 wt% Pd/γ-Fe2O3 cryogel, making them promising materials for the development of direct ethanol fuel cells. [ABSTRACT FROM AUTHOR]

Multi-component reactions for the construction of heterocycles have been fascinated by microwave energy as an alternative technique of heating, owing to the advantages over traditional reflux methods. The heterogeneous catalysts contribute significantly towards recycling, harmless, easy filtration, catalyst preparation, more life span, abundance, and product yields. With novel and creative uses in organic and peptide synthesis, polymer chemistry, material sciences, nanotechnology, and biological processes, the usage of microwave energy has rapidly increased during the past 20 years. This article covers multicomponent reactions involving construction of chromenes, pyridines, pyrroles, triazoles, pyrazoles, tetrazoles, trans and cis julolidines using heterogeneous catalysts under microwave. It provides an overview of contemporary microwave-assisted heterogeneous catalytic reactions. Microwave chemistry is now an established technology with several advantages regarding reaction rate and production yield, improving energy savings as confirmed by many applications. Due to the widespread curiosity in medicinal chemistry, the heterogeneously catalysed construction of heterocycles under microwave irradiation is explored to reduce time and energy. By considering various aspects of economy, eco-friendly, and user-friendly factors, this review focuses on recent advances in the multi-component construction of heterocycles using heterogeneous catalysts under microwave irradiation. This review also discusses the benefits and limitations of reaction conditions and yields from the literature reports for the past five years. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is considered as an ideal fuel for the future. The photo-electrochemical (PEC) water splitting employing semiconducting materials and induced irradiation, preferably of solar spectrum, presents a viable route for H2 production. In this work, self-ordered chromium-doped TiO2 nanotube (CT) was fabricated using in-situ electro-anodization. CT surface modification was then performed by photo-deposition of Pt and Pd particles, producing Pt-CT and Pd-CT catalysts, respectively. Their morphological features, crystallinity, surface composition, and optical absorption have been inspected by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman, and UV–vis absorption spectroscopy. Linear sweep voltammetry, chronoamperometry, and open circuit potential methods have been applied to study PEC activities of Pt-CT and Pd-CT catalysts in a form of electrodes. It was found that Pt-CT and Pd-CT electrodes possess excellent photo-generated electron/hole (e−/h+) separation and transport properties. The enhanced photocurrent responses of 4 and 3 times more than that of CT are revealed for Pt-CT and Pd-CT, respectively. The activity of as-prepared Pt-CT and Pd-CT catalysts was then tested for H2 generation. The maximum amount of the evolved H2 followed decreasing order: 1.08 > 0.65 > 0.26 mL cm−2 h−1 for Pt-CT, Pd-CT, and CT electrodes, respectively, clearly showing the positive contribution of photo-deposited (nano)particles onto CT surface. [ABSTRACT FROM AUTHOR]

The synthesis of CaCO3/Cu2O/GO nanocomposites was developed by sol-gel auto-combustion method. The analysis of structure was completed on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and environmental scanning electron microscopy (ESEM). The XRD spectra of the nanocomposites matched the crystal structure of CaCO3/Cu2O. The average crystal size was 20 nm for Cu2O and 25 nm for CaCO3 nanoparticles. FTIR data showed the absorption bands of Cu2O and GO. Raman spectroscopy data confirmed the formation of GO sheets. ESEM micrographs displayed spherical nanoparticles dispersed in GO sheets. X-ray photoelectron spectroscopy showed the peaks of Cu 2p, O 1s, C 1s, Cu 3s, and Ca 2p. The spectra of optical absorption revealed an absorption band of around 450 nm. The calcium content increase led to a decrease in the optical energy gap from 2.14 to 1.5 eV. The production of hydrogen from NaBH4 across the methanolysis reaction was accelerated by the CaCO3/Cu2O/GO nanocomposites. Therefore, these nanocomposites are superior in catalytic hydrogen production systems. [ABSTRACT FROM AUTHOR]

The present work aims to assess the impact of morphology and reducibility on lanthanum-doped ceria nanocatalysts with controlled morphology on the NO oxidation reaction. Specifically, samples were prepared using a hydrothermal method incorporating lanthanum at varying molar concentrations (0, 5, 10, and 15 mol.%) into ceria with a controlled morphology (nanocubes and nanorods). The structural, compositional, and redox characterization of these catalysts has been performed via scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (X-EDS), inductively coupled plasma (ICP), hydrogen temperature-programmed reduction (H2-TPR), and oxygen storage capacity (OSC). NO oxidation catalytic tests were conducted, and the results were compared with estimated curves (obtained by considering the proportions of the corresponding components), which revealed the presence of a synergistic effect between lanthanum and ceria. The degree of enhancement was found to depend on both the morphology and the amount of lanthanum incorporated into CeO2. These findings may facilitate the optimization of features concerning ceria-based nanocatalysts for the removal of NOx emissions from exhaust gases. [ABSTRACT FROM AUTHOR]

The biological synthesis of nanoparticles with copper, silver, and zinc (Cu, Ag, Zn) is reported in this study, adopting a greener, safe, reliable, and eco-friendly approach by using an aqueous leaf extract of Catharanthus roseus. The synthesised trimetallic nanoparticles were characterised using different characterisation techniques. The UV–visible spectroscopic technique was initially used to assess nanoparticle formation, in which absorption bands were observed at 220, 270, and 370 nm for Cu, Zn, and Ag nanocomposites, respectively. XRD revealed that the average crystalline size of the nanocomposites was 34.67 nm. The roles of reducing and capping/stabilising agents in the synthesis of Cu/Ag/Zn nanoparticles were confirmed by FTIR analysis, and the successful biosynthesis of the same was also confirmed by X-ray energy-dispersive spectroscopy (EDX) analysis. Potential applications of these synthesised trimetallic nanoparticles were evaluated by assessing their antioxidant and catalytic dye degradation activities. The antioxidant activity of the synthesised nanomaterial was studied using the DPPH assay. The catalytic breakdown of the harmful dyes phenol red and eosin yellow was examined using NaBH4 as a reducing agent. The results showed that the nanomaterial's radical scavenging capacity at 1000 ug/mL was 75.76% and the degradation of these dyes was up to 78% in the presence of NaBH4. Furthermore, the biogenic trimetallic nanomaterial exhibited effective catalytic degradation activity against methyl red and phenol red dyes. [ABSTRACT FROM AUTHOR]

The use of algae-based green synthesis of metal oxide nanoparticles (MONPs) for bioremediation is an environmentally friendly and cost-effective alternative to conventional approaches. Algal-mediated synthesis offers several benefits over other biogenic processes, such as plants, bacteria, and fungi, including ease of synthesis, scalability, and rapid synthesis. Algae are readily available in nature, nontoxic, and can produce various types of metal oxide nanoparticles. This approach could significantly accelerate the development of novel algae-nanomaterials with improved properties and performance, leading to more efficient and cost-effective bioremediation of pollutants from water solutions, seawater, and industrial effluent. This review focuses on the biogenic fabrication of metal oxide nanoparticles based on aquatic plants (microalgae and seaweeds) due to their many advantages and attractive applications in pollutant remediation from aqueous solutions. Additionally, photocatalysis is highlighted as a promising tool for the remediation of industrial effluents due to its efficacy, ease of use, quick oxidation, cost-effectiveness, and reduced synthesis of harmful byproducts. [ABSTRACT FROM AUTHOR]

Lignin obtained by hydrogenolysis of lignocellulose biomass is a prospective source of valuable green fuels and chemicals such as monophenols. One of the key factors in the chemical decomposition of lignin to monophenols is an efficient catalyst. Inert porous materials such as hypercrosslinked polymers are suitable catalytic supports for the immobilization of noble and transition metal nanoparticles. However, such polymers do not have acidic properties, which are crucial for catalyzing hydrolysis. In this work, we report novel, efficient catalysts for lignin hydrogenolysis to produce valuable monophenolic compounds. The synthesized catalysts contained Ni, Ru, and Ni–Ru nanoparticles supported on SiO2-coated hypercrosslinked polystyrene (SiO2@HPS). Ni-Ru/SiO2@HPS demonstrated remarkable stability without any loss of the metallic phase and a high yield of monophenols (>42 wt.%) at close to full lignin conversion (>95 wt.%). This result was attributed to the synergy between the two metals and the support's surface acidity. All catalysts were fully characterized by a series of physico-chemical methods. [ABSTRACT FROM AUTHOR]

Abatement of pharmaceutical pollutants from aquatic systems is crucial but remains a challenge. Semiconductor photocatalysis has emerged as an eco-friendly technique that utilizes renewable solar energy to address environmental issues. Naturally occurring and earth abundant hematite (Fe2O3) ores can be incorporated as a suitable component of a photocatalyst. Herein, Brazilian hematite was partially phase transformed into heterophase (consisting of α/γ-Fe2O3) by a simple single-stage heat treatment procedure. The method of synthesis was simple and economical, requiring neither solvents nor concentrated acids. The existence of α/γ-phases in the produced Fe2O3 (FO) was confirmed by X-ray diffraction analysis. After the phase transformation process, the local structure surrounding the Fe atoms was varied as evidenced from X-ray absorption spectroscopy. Given its low toxicity, narrow bandgap, and chemical stability, FO was further combined with g-C3N4 (CN) to form composites. The optical properties of the synthesized CNFO composites confirmed that the visible light harvesting ability of CN was enhanced after combining with FO. The CN sheets were grown uniformly over the surface of FO as evidenced from scanning electron microscopy. The prepared composites could degrade an aqueous solution of ofloxacin (OFX, 10 ppm) under visible light with remarkable efficacy. The performance of CNFO-5% was 4.8 times higher when compared to pure CN. The initial rate constant value for the photocatalytic degradation of OFX by CNFO-5% was 0.1271 min−1. The catalyst was stable even after five repeated cycles of photodegradation. The photoluminescence spectra and electrochemical measurements confirmed the efficient separation and transfer of the photogenerated charges across their interface. The investigations on different scavengers demonstrated that superoxide anion radicals and holes played a significant role in the degradation of OFX. The mechanism for the charge transfer was proposed to be a Z-scheme heterojunction. These results point to the potential of using inexpensive, abundant, and recyclable natural hematite ores as state-of-the-art photocatalysts for the elimination of pharmaceuticals in wastewater. [ABSTRACT FROM AUTHOR]

Currently, the presence of emerging contaminants in water sources has raised concerns worldwide due to low rates of mineralization, and in some cases, zero levels of degradation through conventional treatment methods. For these reasons, researchers in the field are focused on the use of advanced oxidation processes (AOPs) as a powerful tool for the degradation of persistent pollutants. These AOPs are based mainly on the in-situ production of hydroxyl radicals (OH•) generated from an oxidizing agent (H2O2 or O2) in the presence of a catalyst. Among the most studied AOPs, the Fenton reaction stands out due to its operational simplicity and good levels of degradation for a wide range of emerging contaminants. However, it has some limitations such as the storage and handling of H2O2. Therefore, the use of the electro-Fenton (EF) process has been proposed in which H2O2 is generated in situ by the action of the oxygen reduction reaction (ORR). However, it is important to mention that the ORR is given by two routes, by two or four electrons, which results in the products of H2O2 and H2O, respectively. For this reason, current efforts seek to increase the selectivity of ORR catalysts toward the 2e− route and thus improve the performance of the EF process. This work reviews catalysts for the Fenton reaction, ORR 2e− catalysts, and presents a short review of some proposed catalysts with bifunctional activity for ORR 2e− and Fenton processes. Finally, the most important factors for electro-Fenton dual catalysts to obtain high catalytic activity in both Fenton and ORR 2e− processes are summarized. [ABSTRACT FROM AUTHOR]

Recent advances in atmospheric plasmas have led to the formation of nonthermal plasma (NTP). In recent decades, a number of novel plasma diagnostic approaches have been implemented and reported in order to better understand the physics of NTP. The use of NTP is a novel approach to producing reactive oxygen and nitrogen species. Plasma technology has many applications, including electrical device microfabrication, biomedicine, dentistry, agriculture, ozone generation, chemical synthesis, surface treatment, coating, and disease therapy. Furthermore, NTP is thought to be a successful strategy for the degradation of hazardous pollutants in the environment, making it a future hope. Recent studies showed that various operating parameters affect the yield of NTP-based technology. Especially, the presence of a catalyst, properly placed in an NTP reactor, leads to a significant increase in process performance as compared to NTP alone. Scientists have looked at using NTP in conjunction with catalysts to remove various sorts of pollutants from the environment. In this context, review articles are crucial due to the prevalence of NTP-based applications and ongoing developments. This review will describe recent advancements in NTP-based biomedical applications, bacterial inactivation, food preservation and storage, and environmental catalytic formulations. This review could be useful in providing a platform for advancements in biological applications and environmental protection through the use of NTP technology. [ABSTRACT FROM AUTHOR]

Successive grafting of new sorbent bearing amino phosphonic groups based on chitosan nano magnetite particles was performed through successive coupling with formaldehyde. The produced composite was characterized by the high sorption capacity toward rare earth elements (REEs) and consists of different types of functional groups (phosphonic, hydroxyls and amine groups) that are used for enhancing the sorption properties. The chemical modification and the sorption mechanism were investigated through different analytical tools; i.e., FTIR, SEM, SEM-EDX, TGA, BET (surface area) and pHpzc. The sorption was investigated toward Nd(III) as one of the REE(III) members under ultraviolet (UV) and visible light (VL) conditions. The optimum sorption was found at pH0 4 and the sorption capacity was recorded at 0.871 and 0.779 mmol Nd g−1 under UV and VL respectively. Sorption isotherms and uptake kinetics were fitted by Langmuir and Sips and by pseudo-first order rate equation (PFORE) for the functionalized sorbent, respectively. The sorbent showed a relatively high-speed sorption kinetic (20 min). The bounded metal ions were progressively eluted using 0.2 M HCl solution with a desorption rate 10–15 min, while the loss in the total capacity after a series of sorption recycling (sorption/desorption) (five cycles) was limited (around 3%) with 100% of the desorption efficiency, indicating the high stability of the sorbent toward an acidic medium. The sorbent was used for the recovery of REEs from leach liquor residue after pretreatment for the extraction of particular elements. From these results (high loading capacity, high selectivity and high stability against acid treatments), we can see that the sorbent is a promising tool for the selective recovery of rare earth elements in the field of metal valorization. [ABSTRACT FROM AUTHOR]

One of the major concerns that receive global attention is the presence of organic pollutants (dyes, pharmaceuticals, pesticides, phenolic compounds, heavy metals, and so on), originating from various industries, in wastewater and water resources. Rhodamine B is widely used in the dyeing of paints, plastics, textiles, and other fabrics, as well as biological products. It is highly persistent, toxic, and carcinogenic to organisms and humans when directly released into the water supply. To avoid this hazard, several studies have been conducted in an attempt to remove Rhodamine B from wastewater. Metal oxide semiconducting materials have gained great interest because of their ability to decompose organic pollutants from wastewater. TiO2 is one of the most effective photocatalysts with a broad range of applications. Several attempts have been made to improve its photocatalytic activity. Accordingly, we have prepared in this work a series of cerium (Ce) and samarium (Sm) co-doped TiO2 nanoparticles (x = 0.00, 0.25, 0.50, 1.00, and 2.00%) using a sol–gel auto-combustion approach. The influence of Ce–Sm concentrations on the structural, morphology, electronic, and optical properties, as well as the photocatalytic activity, was investigated. Structure and elemental mapping analyses proved the presence of Ce and Sm in the compositions as well as the development of the TiO2 anatase phase with a tetragonal structure and crystallite size of 15.1–17.8 nm. Morphological observations confirmed the creation of spherical nanoparticles (NPs). The examination of the electronic structure properties using density functional theory (DFT) calculations and of the optical properties using a UV/Vis diffuse spectrophotometer showed a reduction in the bandgap energy upon Ce–Sm co-doping. The photocatalytic activity of the synthesized products was assessed on the degradation of Rhodamine B dye, and it was found that all Ce–Sm co-doped TiO2 nanoparticles have better photocatalytic activities than pristine TiO2 nanoparticles. Among all of the prepared nanoparticles, the sample with x = 0.50% demonstrated the best photocatalytic activity, with a degradation efficiency of 98% within 30 min and a reaction rate constant of about 0.0616 min−1. h+ and •O2− were determined to be the most important active species in the photocatalytic degradation process. Besides the high photocatalytic degradation efficiency, these photocatalysts are highly stable and could be easily recovered and reused, which indicates their potential for practical applications in the future. [ABSTRACT FROM AUTHOR]

In heterogeneous catalysis, surfaces decorated with uniformly dispersed, catalytically-active (nano)particles are a key requirement for excellent performance. Beside standard catalyst preparation routines—with limitations in controlling catalyst surface structure (i.e., particle size distribution or dispersion)—we present here a novel time efficient route to precisely tailor catalyst surface morphology and composition of perovskites. Perovskite-type oxides of nominal composition ABO3 with transition metal cations on the B-site can exsolve the B-site transition metal upon controlled reduction. In this exsolution process, the transition metal emerges from the oxide lattice and migrates to the surface where it forms catalytically active nanoparticles. Doping the B-site with reducible and catalytically highly active elements, offers the opportunity of tailoring properties of exsolution catalysts. Here, we present the synthesis of two novel perovskite catalysts Nd0.6Ca0.4FeO3-δ and Nd0.6Ca0.4Fe0.9Co0.1O3-δ with characterisation by (in situ) XRD, SEM/TEM and XPS, supported by theory (DFT+U). Fe nanoparticle formation was observed for Nd0.6Ca0.4FeO3-δ. In comparison, B site cobalt doping leads, already at lower reduction temperatures, to formation of finely dispersed Co nanoparticles on the surface. These novel perovskite-type catalysts are highly promising for applications in chemical energy conversion. First measurements revealed that exsolved Co nanoparticles significantly improve the catalytic activity for CO2 activation via reverse water gas shift reaction. [ABSTRACT FROM AUTHOR]