Search

In this paper, the formation of rhombic ZnO microrods surrounded by ZnO nanorods was realized on the surfaces of zinc foils using a hydrothermal method. The photocatalytic degradation of Rhodamine B solution was used to test the photocatalytic performance of the prepared samples. Compared with the rhombic Zn(OH)F and ZnO microrods grown on zinc foils, the hierarchical micro/nanostructures formed by ZnO nanorods surrounding the surfaces of rhombic ZnO microrods have better photocatalytic performance. The experimental results are mainly due to the fact that the hierarchical ZnO micro/nanostructures formed by ZnO nanorods surrounding the surface of the rhombic ZnO microrods have a larger surface area compared with the rhombic Zn(OH)F and ZnO microrods. More importantly, the photocatalytic circulation experiments indicate that ZnO nanorods grown on rhombic ZnO microrods can be recycled and have a relatively stable photocatalytic performance. [ABSTRACT FROM AUTHOR]

Stable carbocations can catalyze some organic reactions in neutral media. The best result (95% yield) was obtained using 15 mol% of TrCl as a catalyst at 60 °C in ethanol as a solvent over 60 min. As a model, we first examined the reaction of one molecule of 4-chlorobenzaldehyde with two molecules of acetamide, and the amount of catalyst, temperature and solvent were investigated. [Extracted from the article]

The zinc complex Zn(C6F5)2(toluene) (1) behaves as a very active and selective catalyst in cyclohexene oxide (CHO) polymerization to produce poly(cyclohexene oxide) (PCHO) by the trans-ring-opening of CHO with remarkable TOF values at room temperature. The ring-opening copolymerization (ROCOP) of CO2 with CHO catalysed by 1 yields poly(cyclohexene carbonate) (PCHC) when using benzyl alcohol (BnOH) as an initiator at 120 °C. The 1H NMR monitoring of the in situ reaction of 1 with BnOH highlighted the formation of the dinuclear species [(C6F5)2Zn2(BnO)2 (2) that was isolated and found an active catalyst in the ROCOP of CO2 with CHO in the absence of initiators. Interestingly, PCHCs by 2 in solventless conditions show polydispersity index (Mw/Mn) values close to 2, corresponding to those expected for a single-site catalyst; on the contrary, a broader polydispersity index of the polymer products was found in toluene solution, suggesting the formation of new zinc catalysts during the polymerization reaction. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of sodium diclofenac, a nonsteroidal anti-inflammatory drug, was carried out comparing the activity of cobalt, nickel, and zinc ferrites as catalysts, using UV radiation and hydrogen peroxide. The materials were characterized by X-ray diffraction and by Fourier-Transform Infrared, UV–Visible and X-ray photoelectron spectroscopies. It was determined that all samples had spinel structure: ZnFe2O4 normal spinel, CoFe2O4 partially inverse spinel and NiFe2O4 inverse spinel. A simulated solution of 40 ppm of sodium diclofenac was completed degraded within 4 h meanwhile 86 to 83% of total organic carbon was obtained. The photocatalytic process take place via radical mechanism. The decrease of samples pH could be attributed to the formation of small acid molecules like oxalic and acetic acid, which are by-products of sodium diclofenac photodegradation. The reaction kinetic was also studied, and the photo-Fenton degradation of sodium diclofenac could be described by first-order model with a linear correlations coefficient R2 > 0.95 in all cases. The information based on kinetic studies can be applied for developing reactors for pollutant elimination, especially for industrial scale. [ABSTRACT FROM AUTHOR]

Zn:Cr mixed oxide catalyst was examined as an effective and recyclable catalyst for the synthesis selected pyrimidine derivatives in high yield. The catalyst was characterized by FT-IR, XRD, BET, SEM, EDX and Zeta potential analysis. Substituted 4-aryl-6-(3-coumarinyl) pyrimidine-2(1H)-ones were prepared in high yield and purity via the cyclocondensation of urea and 3-acetylcoumarin with substituted aldehydes in the presence of a catalytic amount of Zn:Cr mixed oxide catalyst as Lewis acid at ambient temperature. The effect of the molar ratio of the catalyst was also studied, and as a result, Zn:Cr (10:1) showed better catalytic performance than Zn:Cr (1:1) at identical reaction conditions. Furthermore, catalyst stability was intact as confirmed by the catalyst recyclability experiment. [ABSTRACT FROM AUTHOR]

Amines and alcohols with a fully substituted α-carbon are structures of great value in organic synthesis and drug discovery. While conventional methods towards these motifs often rely on enantioselective carbon-carbon or carbon-heteroatom bond formation reactions, a desymmetric method is developed here by selectively hydrosilylating one of the esters of easily accessible α-substituted α-amino- and -oxymalonic esters. The desymmetrization is enabled by a suite of dinuclear zinc catalysts with pipecolinol-derived tetradentate ligands and can accommodate a diverse panel of heteroatom substituents, including secondary amides, tertiary amines, and ethers of different sizes. The polyfunctionalized reduction products, in return, have provided expeditious approaches to enantioenriched nitrogen- and oxygen-containing molecules, including dipeptides, vitamin analogs, and natural metabolites. Chiral α-tertiary amines and tertiary alcohols are prevalent in bioactive molecules yet challenging targets to access. Here, the authors provide a dinuclear zinc-catalyzed desymmetric approach based on readily available malonic esters. [ABSTRACT FROM AUTHOR]

The activation of C–H bonds for the synthesis of highly valued chemicals is still a challenging task. Herein, a nitrogen-doped carbon supported single atom Zn catalyst (Zn–N–C) was fabricated via a ligand-stabilized pyrolysis strategy, in which 2,2′-bipyridine (bipy) served as a ligand and graphitic carbon nitride (g-C3N4) served as a directional 2D-template and a nitrogen source. The results of high-angle annular dark field aberration corrected scanning transmission electron microscopy (HAADF-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy indicated that Zn species are present as isolated single sites and stabilized by nitrogen in the Zn–N4 structure. The optimized Zn–N–C-900 catalyst displayed superior catalytic performance for the selective oxidation of C–H bonds. In particular, the Zn–N–C-900 catalyst can be reused fifteen times without obvious decay in either activity or selectivity. Density functional theory calculations were conducted to reveal the reaction mechanism. The results indicated that the high valence Zn＝O species generated on Zn–N–C-900 were the crucial active centers for the activation of C–H bonds. [ABSTRACT FROM AUTHOR]

Here, we report a facile synthesis of porous zinc-titanium oxide based mixed oxide nanoparticles having Zn/Ti molar ratio 1:2 based on evaporation-induced sol–gel route using Pluronic triblock copolymer P123 as a template. Use of volatile ethanolic media during the evaporation-induced self-assembly (EISA) method facilitates the formation of Zn–Ti mixed oxide heterostructure. Powder XRD data reveals that the composite material displayed ZnTiO3/TiO2 phases. Morphology, composition, porosity, nanostructure and thermal stability have been systematically investigated using small angle powder XRD, FE SEM-EDS, TEM, N2 sorption, FT IR and TG-DTA techniques. The observed BET surface area of Zn–Ti mixed oxide was 231 m2 g−1 with a typical mesopore diameter (~ 5 nm) mostly arising from interparticle void space. The Zn–Ti mixed oxide catalyst showed bifunctional activity for Friedel–Craft benzylation of aromatics using benzyl chloride as well as partial oxidation of olefins under mild reaction conditions using dilute aqueous H2O2 as oxidant. Zn–Ti based porous nanoparticles synthesized using Pluronic P123 copolymer surfactant via EISA method has shown a very high surface area of 231 m2 g−1 and a significant bifunctional role for liquid phase oxidation and benzylation reaction. [ABSTRACT FROM AUTHOR]

A novel and green nanomagnetic zinc catalyst were fabricated via the immobilization of zinc (II) complex on the surface of magnetic nanoparticles modified with phenanthroline (MNPs-Phen-Zn(II)). The structure of MNPs-Phen-Zn(II) nanomaterial was characterized by a series of spectroscopic techniques including FT-IR spectroscopy, SEM, TEM, EDX, XRD, VSM, and ICP-OES. The resulting zinc nanomagnetic catalyst was shown high catalytic activity for the synthesis of disubstituted alkynes via C(sp²)–C(sp) cross-coupling reactions of alkynes with aryl iodides under eco-friendly conditions. To the best of our knowledge, it is the first report on the utilization of zinc nanomagnetic catalyst for the Sonogashira type cross-coupling reaction of alkynes with aryl iodides in the absence of added Pd and Cu sources. The simple preparation of the catalyst from commercially available materials, excellent chemoselectivity, easy separation of products, and straightforward recovery and reusability of the catalyst with unaltered activity make our procedure a green and practical method. [ABSTRACT FROM AUTHOR]

The composition of the catalyst layer plays an important role in the carbon dioxide reduction reaction (CO 2 RR), since it influences greatly the mass diffusion rate and the accessibility of active sites. Until now, tremendous efforts have been dedicated to the development of cathode materials with innovative characteristics, while scarce efforts have been concentrated on the study of the catalyst layer aiming at maximizing the performance of the electrodes toward the CO 2 RR. This work focuses on a full investigation of the key electrode components and their effects on the CO 2 RR performance. It is found that all key components such as Nafion binder, zinc oxide catalyst and carbon black conductor significantly affect the current density and the faradaic efficiency for carbon monoxide (CO) formation. [Display omitted] • A thorough study of the composition of a ZnO-based electrode is conducted for CO 2 RR. • All key components show significant effects on CO selectivity and production rate. • Nafion favors charge transfer while it limits electron transport and CO 2 diffusion. • Carbon black considerably increases electrical conductivity. • ZnO loading is associated with the number of active sites and their accessibility. [ABSTRACT FROM AUTHOR]

BACKGROUND: A mesoporous zinc‐based pyridine‐2,5‐dicarboxylate metal–organic framework (Zn‐based MOF) catalyst was prepared by a solvothermal method. The catalytic potency of Zn‐based MOF for the one‐pot synthesis of 3,3‐(arylmethylene)bis‐1H‐indole derivatives was investigated. RESULTS: Various analytical techniques were used to characterize the physicochemical structure of Zn‐based MOF catalyst, including powder X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy–energy‐dispersive X‐ray analysis, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller surface area analysis. Zn‐based MOF was then employed as a catalyst for the catalytic one‐pot transfer synthesis of 3,3‐(arylmethylene)bis‐1H‐indole derivatives. Optimizations of Zn‐based MOF catalyst in terms of effect of solvent and reaction time were investigated. CONCLUSIONS: Zn‐based MOF catalyst was synthesized by solvothermal treatment, characterized and used as a Lewis acid catalyst for the synthesis of biologically active 3,3′‐(arymethylene)bis‐1H‐indole derivatives. The catalyst offers notable benefits such as reusability of catalytic character, easy separation, nontoxicity, large pore size and providing excellent yield of 3,3′‐phenylmethylene‐1H‐indole derivatives. Zn‐based MOF was confirmed as containing tetragonal phase with large pore diameter, morphology looking like a spherical core and exhibiting no significance loss of catalytic performance when used in organic synthesis for three to four reaction runs. Thereby Zn‐based MOF was evidenced as showing excellent catalytic activity. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

CoxZn1−xO system (0 ≤ x ≤ 0.2) was synthesized using the solution combustion method with urea as a fuel source. Photocatalytic tests were performed under visible light to assess the Basic Blue 41 (BB41) conversion. Various characterization techniques, including XRD, FT-IR analysis, SEM, EDS, XRF, BET-surface area, and DRS were used to investigate the composition, structure, and morphology of the synthesized catalysts. In addition, the density functional theory calculation was used in order to study the electronic properties of the ZnO structure. The Box–Behnken model was valid for describing the degradation of BB41 dye according to the analysis of variances results. A maximum conversion of 100% for BB41 dye has been reached with high mineralization and important removal of chemical oxygen demand. The optimum conditions for BB41 conversion are reported. On the other hand, the reuse tests of the best catalyst showed high-performance stability after five cycles. Furthermore, the activity of superoxide ions (O2·−) and hydroxyl radicals (OH.) as the spices responsible for BB41 dye conversion was well confirmed by the free radicals scavenging tests. The use of Box–Behnken optimization and DFT calculation applied to the synthesized catalysts proves to be a very suitable procedure to establish the operating conditions under which the synthesis strategy of the CoxZn1−xO catalyst in its activity in the visible region performs an excellent efficiency for the degradation of organic dyes and makes contributions to the current literature related to the field of environmental technology. [ABSTRACT FROM AUTHOR]

We examined three other common green catalysts at 10 mol% catalyst loading and found PA to be superior in terms of yields and reaction times (Table 1, Entries 1-3, 5) at 80 °C temperature. Using the optimized reaction conditions, we then traced the scope of this reaction and prepared a series of substituted bis-4-hydroxycoumarins (Table 2, compounds B 3a b B 3k b ). In further probing reaction parameters, we found that a decrease in the catalyst loading led to a slightly lower yield (Entry 6) and that an increase in catalyst loading did not improve the yield (Entry 7). We began the present study with an exploration of the one-pot condensation reaction of one mmole of 4-methoxybenzaldehyde and two mmoles of 4-hydroxycoumarin heated under solvent-free conditions at 80 °C temperature using PA as catalyst (Scheme 1, R = 4-CH SB 3 sb OPh). [Extracted from the article]

The catalytic enantioselective alkynylation of isatins, catalyzed by a Zn(OCOCF3)2/chiral bis(sulfonamide)‐diamine (BSDA) catalyst under mild condition, has been developed. The desired chiral 3‐alkynyl‐3‐hydroxy‐2‐oxindoles were obtained in moderate to excellent yields (up to 96%) and good to excellent enantioselectivites (up to 97% ee). The reaction is broad in scope with respect to aryl‐substituted terminal alkynes and substituted isatins. [ABSTRACT FROM AUTHOR]

Summary: Structural optimization and electrocatalyst utilization in air cathodes have been identified as two major factors affecting the overall performance of a lithium‐air battery. Herein, a cobalt@porous carbon composite, Co@C(700‐1000) was obtained by facile annealing of a Co/Zn‐bimetallic metal‐organic framework (MOF). In the Co/Zn‐MOF, cobalt cluster was used as a precursor of the catalyst and zinc cluster as a sacrificial template to generate meso‐ and macropores. The lithium‐air battery with the assembled Co@C(700‐1000) air cathode revealed a specific capacity as high as 4 mAh cm−2. Furthermore, the battery exhibited high cycling stability up to 67 cycles (limited capacity of 0.5 mAh cm−2). The high cell performance can be in relation to the catalytic activity of uniformly disseminated cobalt nanoparticles in the porous carbon matrix and the rapid diffusion and transport of Li+ and O2 owing to the optimized pore‐distribution characteristics. Using a bimetallic MOF‐derived material, this study sheds fresh light on the design of an air cathode for lithium‐air batteries. [ABSTRACT FROM AUTHOR]

The synthesis of biologically active 2‐substituted benzimidazoles and benzothiazoles was developed using Zn(L‐Pro)2 as catalyst in ethanol at room temperature in an aerobic oxidative cyclization reaction involving o‐phenylenediamine and 2‐aminothiophenol with various substituted aldehydes. This process offers a quick and eco‐friendly way to synthesize a variety of pharmacologically important benzothiazoles and benzimidazoles. [ABSTRACT FROM AUTHOR]

A simple, efficient and green approach to the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones has been developed via one-pot three-component reaction of aromatic aldehyde, malononitrile and phthalhydrazide catalyzed by zinc–proline complex (Zn[L-proline]2) using H2O: PEG400 = 6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method. [ABSTRACT FROM AUTHOR]

In the present work, a novel Zn salen complex supported on MnCoFe2O4 magnetic nanoparticles, MnCoFe2O4@SiO2-Pr-NH-SA&Zn (MCF@SiO2-Pr-NH-SA&Zn) was easily synthesized by a clean method and fully characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction, Field emission-scanning electron microscopy, Energy dispersive X-ray analyzer, Transmission electron microscopy, Inductively coupled plasma-optical emission spectrometry, Thermogravimetric and Vibrating sample magnetometery analyses. Moreover, the activity of the prepared complex as a heterogeneous catalyst was investigated in Biginelli-like reaction via three component reaction ethyl acetoacetate or dimedone/ or barbituric acid, urea/ or thiourea and different aromatic aldehydes. The structure of new prepared 3,4-dihydropyrimidin-2 (1H)-ones/thions was properly identified by FT-IR, 1H- and 13C-NMR spectroscopy data. Some important advantages of this procedure include easy separation of catalyst by a magnet, short reaction times, excellent yield of products, solvent free, easy work-up and reusability of the catalyst during 6 runs of the used model reaction. [ABSTRACT FROM AUTHOR]

A highly stable and efficient heterogeneous catalyst was successfully prepared by hydrothermal reaction of Zinc nitrate with citric acid. To produce a novel Zn‐based MOF catalyst, Zn ions were coordinated with the ligand functional groups that can be regarded as an alpha‐hydroxy acid containing three carboxylic acids (COOH) and one hydroxyl (OH) group attached to the three‐carbon skeleton. It was found that the Zn‐CA‐MOFs compound can participate as a catalyst in the synthesis of 5‐substituted 1H‐tetrazole and pyranopyrazole molecules, selectively and efficiently with high yield in a short period of time. As presented, the catalyst demonstrates excellent reusability and stability and can be recycled up to five times without significant loss of reactivity. Heterogeneity analysis showed that no leaching of active Zn species occurred during the recycling process of the heterogeneous Zn‐CA‐MOFs. [ABSTRACT FROM AUTHOR]

The zinc ion is used as a catalyst to effectively replace the traditional copper ion catalyst to participate in the redox reaction of hydrazine hydrate and hydrogen peroxide to generate diimide to selectively hydrogenate the carbon–carbon double bonds in the nitrile butadiene rubber (NBR) latex to prepare hydrogenated NBR (HNBR). The optimized zinc ion catalytic hydrogenation system was obtained through orthogonal design experiment screening. Among them, the hydrogenation of NBR latex with zinc chloride as a catalyst can obtain HNBR-ZnCl2 products with high hydrogenation degree (90.58%), high thermal stability, and high regularity. Using zinc ions as a catalyst instead of copper ions can effectively improve the damage of copper ions remaining in the hydrogenated product on the thermal-oxidative aging resistance performance of rubber. Compared with HNBR hydrogenated by copper ions, HNBR hydrogenated by zinc ion catalysts has better thermal-oxidative aging resistance performance. [ABSTRACT FROM AUTHOR]

In view of the problem that 1,1,2,2,3,3,4−heptafluorocyclopentane (F7A) is difficult to separate and recover when mixed with tert−amyl alcohol (TAA) for further application, leading to high cost, we designed a reactive distillation process, and conducted experimental research on the recycle effect of F7A, aiming to recycle F7A with high purity and yield from the used compound cleaning agents, thereby greatly reducing the cost. With zinc chloride as the catalyst, the dehydration reaction of TAA was carried out and the reaction kinetics were measured. Besides, the reaction kinetic equation was obtained by the correlation of experimental data. Investigations were also conducted on the effects of catalyst amount, reaction temperature, and reflux ratio on the conversion of TAA and the recovery of F7A. Based on the reaction kinetics and process optimization, the reactive distillation process for recovery of F7A was simulated to analyze the effects of stage number, feed stage, reflux ratio, and heat duty on the reactive distillation column. Under the optimized operating conditions, F7A with purity of 99.4% and recovery of 73.1% was obtained by the reactive distillation process. [ABSTRACT FROM AUTHOR]

In this work a series of chitosan‐based catalysts with ranging hydrophobic/hydrophilic balance are successfully prepared by varying the ionic liquid and hydrocarbon chain length attached to chitosan. The chitosan modified with eight carbon units displayed efficient catalytic activity for the conversion of a wide range of epoxides to their corresponding cyclic carbonates under 1 atmosphere pressure of carbon dioxide without cocatalyst and solvent. The optimized catalyst was able to convert even diepoxides and sterically bulky epoxides like t‐butyl glycidyl ether to their corresponding cyclic carbonates. This study provides an insight into catalyst designing based on possible molecular interaction between reactants and active sites of the catalyst. [ABSTRACT FROM AUTHOR]

A diverse suite of Zn-SAPO-34 catalysts was synthesized employing three distinct methodologies for the incorporation of zinc species: thermal ion exchange, wet impregnation, and physical mixing. The catalysts were characterized using various analytical techniques including XRD, FT-IR, BET, SEM, XRF, XPS, NH 3 -TPD, and Py-IR, to elucidate the crystal structure, morphology, surface acidity, and the presence of zinc species within the catalysts. The study showed that the method of zinc introduction markedly impacts the physicochemical properties of the catalysts. Different approaches to introducing zinc species significantly influence the acid strength and type on the catalyst surface, with variations in the existing states of zinc across the catalysts. Specifically, zinc species introduced via thermal ion exchange coexist as ZnOH+ and ZnO within the catalyst, whereas those from wet impregnation and physical mixing are individually present as either ZnOH+ or ZnO. Furthermore, the study examined the catalytic performance of these Zn-SAPO-34 catalysts in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Catalysts prepared via thermal ion exchange exhinited superior performance, achieving an remarkable HMF yield of 94.6 %. Additionally, in situ infrared technology was used to investigate the effect of zinc species introduction on the fructose dehydration process, indicating suggesting that the introduction of zinc species enhances the transformation of fructose molecules. • The preparation method directly influences the state of Zn species on the catalysts. • The states of Zn species on various catalysts encompass ZnO and ZnOH+. • The catalyst prepared via thermionic exchange exhibits the highest yield of HMF. • The introduction of zinc species enhances the transformation of fructose molecules. [ABSTRACT FROM AUTHOR]

Catalytic CO 2 hydrogenation using green hydrogen is a promising approach for mitigating CO 2 emissions and utilizing CO 2 as a feedstock. While Fe-based catalysts produce long-chain hydrocarbons under high-pressure CO 2 hydrogenation reactions, the C 2+ hydrocarbon yield tends to be insufficient at low-pressure conditions over the catalyst. This study reports the enhancement of light olefin selectivity of CO 2 hydrogenation over Fe-based catalysts at low pressure via nanoscale hybridization with manganese (Mn) and zinc (Zn) oxides. The resulting hybridized catalyst exhibited distinctive performance in terms of CO 2 hydrogenation to light olefins at relatively low pressure (0.7 MPa) in terms of CO 2 conversion rate and C 2 –C 4 yield with high olefin rates. Mn and Zn incorporation in Fe oxide decreased the reduction temperature, forming more Fe carbide phase. CO 2 adsorption capability at relevant temperatures seems to be improved when Mn and Zn are present. This mixed oxide precatalyst approach can be extended to other elements. [Display omitted] • Fe, Mn and Zn nanohybrid catalysts were synthesized via reduction of Spinel-type Mn x Zn (2-x) Fe 4 O 8 with different Mn/Zn ratio. • The optimized catalyst, Mn 1.5 Zn 0.5 Fe 4 O 8 , exhibited 50.5 % selectivity toward C 2 –C 4 products at a CO 2 conversion of 26.6 %. • Reaction orders of both H 2 and CO 2 over Mn 1.5 Zn 0.5 Fe 4 O 8 , were uniquely ∼ 0.5th, indicating their non-competitive adsorption. • The optimized catalyst, Mn 1.5 Zn 0.5 Fe 4 O 8 , exhibited significantly superior durability over 60 h. [ABSTRACT FROM AUTHOR]

• A novel bimetallic (Ni-Cu) doped zinc ferrite-based catalyst has been prepared using by hydrothermal method. • The confirmation of parameters such as pore size, pore volume, and surface area were obtained through BET analysis. • Ni-Cu doped zinc ferrite-based photocatalysts exhibited MB degradation up to 99 % in 180 min. • The Ni-Cu nanocomposites proved to be reusable, showcasing their potential for sustainable applications. A novel bimetallic nickel-copper doped zinc ferrite based catalyst has been synthesized using the hydrothermal method. The nano-sized bimetallic (Ni-Cu) zinc ferrites were embedded with graphene oxide (GO). The characterization of nano-sized bimetallic (Ni-Cu) zinc ferrites with graphene oxide (GO) involves a comprehensive set of analytical techniques to determine their elemental composition, structural properties, and morphological features. The prepared materials were also subjected to structural and morphological evaluation through FTIR, Raman, XRD, TGA, UV–vis spectroscopy, and SEM with EDX. The experiment for the photodegradation of the selected model pollutant dye, methylene blue was conducted using the prepared materials. This means that the present photocatalyst has a high efficiency of degrading the pollutant to a tune of 99 % within 3 h. When the amount of GO in the prepared nanocomposite was 40 %, there was the perfect result in terms of no degradation of MB. It reduced and deteriorated the degree of band gap energy of the MB dye. The photocatalyst activity was proven to be repeatable; the sample's use was again possible. A decrease in the band gap energy implies that the improved photocatalyst material becomes more efficient at absorbing light energy. This enhanced light absorption promotes the generation of electron-hole pairs, which are essential for catalytic reactions. Therefore, the reduction in band gap energy likely contributes to the catalyst's heightened ability to initiate the degradation of the MB dye, ultimately leading to more effective pollutant removal. In the future, the synthesized sample can be reused without significant loss in its catalytic efficiency, underscoring the stability and durability of the material. The current study has paramount importance for real-world applications; reliable performance over multiple cycles ensures that the catalyst remains effective in addressing pollution challenges over prolonged periods. [ABSTRACT FROM AUTHOR]

New formulations of unsupported tetrametallic catalysts derived from layered double hydroxides (LDH) compounds were synthesized by a constant pH coprecipitation method, characterized, and evaluated in the selective hydrodesulfurization (HDS) of thiophene in the presence of cyclohexene. The layered double hydroxides were prepared using terephthalate (C 8 H 8 O 2)2- as the interlayer anion with nominal aluminum molar fraction of 0.5, and nominal cobalt to MII (M = Zn or Mn) ratios of 0.2, 0.4 and 0.6. Molybdenum introduction in the LDH precursor was accomplished by an ion exchange process using the heptamolybdate anion. The calcined Mn samples showed a higher surface area than those obtained from Zn. The sulfidation was carried out in situ with a heating ramp up to 673 K and the catalysts were evaluated in a tubular flow reactor. The catalytic evaluation of Zn and Mn-based materials for simultaneous thiophene HDS and cyclohexene hydrogenation (HYD) was conducted at 573 K and 20 bar. The results show that the Zn-based unsupported catalysts synthesized here exhibited higher selectivity for the HDS reaction than an industrial one. [Display omitted] • New selective catalysts for naphtha hydrodesulfurization from hydrotalcite-type compounds were synthesized. • Textural and MoS 2 lamellae stacking differences were observed for materials with different divalent cations. • Catalysts containing zinc cation appear to be more selective for naphtha HDS. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Zn (1-x) Cd x S solid solutions can only be synthesized under alkaline conditions. • Under acidic conditions and high Cd content, the final products were CdS/ZnS composites. • Zn 0.6 Cd 0.4 S catalyst exhibits excellent photocatalytic activity for dye removal and H 2 evolution. • Zn 0.6 Cd 0.4 S catalyst has good photocatalytic stability and the AQY was 9.16 % at 400 nm. Designing an efficient and stable dual-functional photocatalyst for organic dyes removal and hydrogen (H 2) evolution has emerged as a crucial research direction to address the pressing issues of severe environmental pollution and the energy crisis. In this work, Zn (1-x) Cd x S solid solutions were prepared by a one-step hydrothermal method, with variations in both the pH of the precursor solutions and the molar ratios of Cd/Zn. The as-prepared Zn (1-x) Cd x S solid solutions featured small crystallite size and controllable band structure, which was conducive to photocatalysis. When the pH of the precursor solution was 8 and the molar ratio of Cd/Zn was 0.4:0.6, the resulting Zn 0.6 Cd 0.4 S-8 solid solution exhibited remarkable photocatalytic activities towards RhB (94.6 %), MO (54.9 %) and MB (89.3 %). Furthermore, the H 2 evolution rate of Zn 0.6 Cd 0.4 S-8 solid solution modified with Pt can reach 7.01 mmol·g−1·h−1 with 0.5 M Na 2 S-Na 2 SO 3 as sacrificial agent. Zn 0.6 Cd 0.4 S-8 solid solution maintained good photocatalytic stability and the apparent quantum yield (AQY) was 9.16 %. Moreover, the possible photocatalytic mechanism was also proposed. [ABSTRACT FROM AUTHOR]

• In this study, a series of heterometallic hexanuclear complexes (viz Nd 4 Zn 2 L 2 (1) and Eu 4 Zn 2 L 2 (2)) were synthesized with a Schiff base ligand and fully characterized. • The complexes have good chemical stability, and high thermal stability. • The complexes can effectively catalyze CO 2 and epoxides into cyclic carbonates under mild condition. • The complexes can be reused to preserve the structure's integrity and retain their catalytic activity at the same level even after five rounds of catalysis. • These complexes can show broad substrate scope of epoxides. Reasonable and high efficient utilization of carbon dioxide (CO 2) has always been considered as a kind of green and sustainable development strategy. However, the efficient chemical conversion of CO 2 into value-added products has been limited due to lack of efficient catalysts. Herein, two novel heterometallic hexanuclear complex catalysts (viz Nd 4 Zn 2 L 2 (1) and Eu 4 Zn 2 L 2 (2)) were designed and synthesized, which featuring unique hetero-multinuclear units. The heterometallic hexanuclear complex catalysts not only have multi-bimetallic catalytic sites (Ln3+ and Zn2+) which can absorb more molecules and be beneficial to the improvement of catalytic performance, but also have the potential to further expand the chemical fixation of CO 2 with epoxides avoid the harsh reaction conditions. Using the synthesis of propylene carbonate (PC) by cycloaddition reaction of propylene oxide (PO) and CO 2 as a model reaction, the as-prepared catalysts and catalytic system showed high turnover frequencies (TOFs) under the mild condition instead of harsh reaction conditions. More importantly, these catalysts can be reused to preserve the structure's integrity and retain their catalytic activity at the same level even after five rounds of catalysis. The excellent regeneration performance indicated that the as-prepared heterometallic hexanuclear complex catalysts can be reused many times. In addition, the catalytic system also exhibited a wide range of substrates for epoxide. These results predict that the proposed heterometallic hexanuclear complex catalysts and catalytic system have great potential toward CO 2 adsorption and catalytic conversion. This work may build up a new synthetic route for tailoring more new heterometallic complex catalysts with excellent catalytic activity and applied in various fields of application. [Display omitted] [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of CO 2 into a single product provides a promising strategy for recycling and utilizing this greenhouse gas, but it remains challenge. Herein, a ZnFeAlO 4 /Zn-SAPO-34 composite catalyst has been designed, which exhibits a space-time yield of propane of 4.21 mmol g−1 h−1, along with a long-term stability of over 180 h. It was found that the Fe sites in ZnFeAlO 4 spinel are conductive to accelerate CO 2 hydrogenation into CH 3 OH, which are stable enough to prevent reduction and carbonization. Characterization results proved that more Brønsted acid sites of SAPO-34 and the addition of Zn species into SAPO-34 zeolite are favorable to form active methylbenzenes with four or five methyl groups, preferentially leading to the formation of propylene via the aromatics-based cycle, which could be hydrogenated to propane. This work presents a feasible strategy in designing an efficient composite catalyst for the synthesis of specific single products from CO 2 hydrogenation. [Display omitted] • The ZnFeAlO 4 /Zn-SAPO-34 composite catalyst was designed and prepared. • The Fe sites in ZnFeAlO 4 spinel play an important role in enhancing CO 2 activation. • The Brønsted acid sites of SAPO-34 zeolite and the addition of Zn species can promote the formation of propane.. • The optimal space-time yield of propane reached 4.21 mmol g−1 h−1 over the ZnFeAlO 4 /Zn-SAPO-34 composite catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • A coin-like iron-zinc-based nitrogen-doped carbon composite (FeZn-NC) was fabricated. • The correlation between active sites and ORR performance was verified. • FeZn-NC catalyst exhibits high catalytic kinetics for oxygen reduction reaction. • FeZn-NC catalyst possesses excellent catalytic performance for zinc-air battery. Fe/N/C is recognized promising catalyst for oxygen reduction reaction (ORR), playing a pivotal role in advancing the commercialization of proton exchange membrane fuel cells. However, an inadequate ORR activity hinders its potential applications. Here, we present the preparation of M–Nx–C (M = Fe, Zn) bi-active sites for promoting ORR. By the pyrolysis of benzimidazole salts, a porous coin-like iron-zinc-based nitrogen-doped carbon materials (FeZn-NC) catalyst was synthesized with abundant active sites. X-ray photoelectron spectroscopy and transmission electron microscopy characterizations indicated the successful doping of Zn and Fe within the carbon framework. Electrochemical measurements demonstrated great positive half-wave potential (0.90 V), high limiting current density (5.15 mA·cm−2), excellent methanol resistance, and good stability of FeZn-NC, compared to commercial Pt/C catalysts. Furthermore, an investigation into correlation between doping content of Fe and the ORR performance was carried out. As an cathode catalyst of zinc-air battery, FeZn-NC exhibited more significant advantages, including a high open-circuit voltage (1.54 V), enhanced power density (199.89 mW·cm−2), good specific capacity (771.9 mAh g Zn −1 ), and enhanced stability compared to Pt/C. By presenting an approach for the controlled synthesis of metal-doped carbon materials, this work establishes the groundwork for potential applications in catalytic fields, as demonstrated by the prepared FeZn-NC. [ABSTRACT FROM AUTHOR]

Zinc-doped cobalt nickel sulfides coupled with polypyrrole hollow nanospheres grown on carbon paper (Zn-CoNiS/PHS/CP) were developed by unipolar pulse electrodeposition (UPED) method as efficient and stable electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting in neutral media for the first time. With abundant active sites intrigued by moderate Zn doping, the optimized Zn 10 -CoNiS delivers improved catalytic performance with small overpotentials of 213 mV and 414 mV to achieve the current densities of 10 mA cm−2 for HER and OER respectively, and outstanding long-term stability. The water electrolyzer device with Zn 10 -CoNiS as both anode and cathode delivers a current density of 10 mA cm−2 at a cell voltage of 1.896 V in neutral media. The low charge transfer resistance of Zn-CoNiS and confinement effect of 2D Ni 9 S 8 /Co 9 S 8 nanosheets on 0D ZnS nanodots endow the bifunctional electrocatalysts with efficient activity and high stability, providing a competitive candidate for green hydrogen production. [Display omitted] • Unipolar pulse electrodeposition is used to construct cation-doped bimetallic sulfide. • Zn-CoNiS shows advanced catalytic activity and high stability for both HER and OER. • Doping of Zn optimizes electronic structure and enhances conductivity of Ni 9 S 8 /Co 9 S 8. • 0D/2D confinement effect promotes long-term stability of Zn-CoNiS in neutral media. • Zn 10 -CoNiS bifunctional catalyst delivers superb overall water splitting performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • CaO and Zn/HBeta cascade catalysts for aviation fuel from wastes was investigated; • High Zn loading in Zn/HBeta favors the production of straight-chain alkanes; • CaO-Zn/HBeta cascade reduced 50 wt% Zn/HBeta consumption for oil production; • CaO to Zn/HBeta ratio by 1:1 yields oil containing 38.09 area% of C8–C16. In this study, the co-pyrolysis of camphorwood and low-density polyethylene employing a cascade catalyst system consisting of CaO and Zn-modified HBeta in a fixed-bed reactor was investigated for the production of aviation fuel hydrocarbons (C8–C16). The effect of Zn loading on HBeta, CaO to Zn/HBeta mass ratio, and the feedstock to catalyst mass ratio on both oil yield and composition was investigated. Results revealed that loading Zn onto HBeta led to ZnO cluster and oxygen-bridged Zn dimers ([ZnOZn]2+) formation, which affects HBeta's acid properties and aromatization capacity. The 10 wt%Zn/HBeta catalyst with more ZnO content exhibited weak acid sites, and moderate aromatization capacity, increasing oil yield from 32.06 to 44.25 wt% compared to 3 wt%Zn/HBeta and favoring presence of straight-chain components in oil products. CaO also enhanced straight-chain alkane formation. The highest oil yield, reaching 48.44 wt%, was obtained when CaO and 10 wt%Zn/HBeta cascade by a 1:1 mass ratio was adopted, producing oil with aviation fuel with a maximum yield of 18.45 wt%, and selectivity of 38.09 area%, of which 26.54 area% being aromatics and 11.55 area% being alkanes. Furthermore, the feedstock-to-catalyst ratio influenced the products significantly, with lower feedstock-to-catalyst ratio enhanced aromatization and the ratio of 2:1 recommended. Therefore, this cascade catalytic approach, which combines cost-effective CaO and 10 wt%Zn/HBeta catalysts shows significant potential for enhancing bio-aviation fuel production from solid wastes. Moreover, it provides a viable and promising solution for addressing concerns related to low oil yield and excessive aromatization. [ABSTRACT FROM AUTHOR]

Herein, the triple-atomic nanozyme (TAzyme) Fe/Zn/Ir with high peroxidase (POD)-like and luminescent properties is employed to sensitively detect melatonin (MT) with colorimetric and luminescent modes. [Display omitted] • The triple-atomic enzyme (TAzyme) Fe/Zn/Ir is prepared without high temperature and pyrolysis procedures. • Fe/Zn/Ir not only has high POD-like activity, but also possesses interesting luminescence properties. • The developed dule-mode detection provides new conception to detect other biological molecules. • Fe/Zn/Ir is fabricated into the test swabs which can effectively monitor MT in the portable and naked-eye way. Herein, a novel ternary-atomic Fe/Zn/Ir nanozyme (Fe/Zn/Ir TAzyme) with peroxidase (POD)-like and luminescence properties is fabricated through coordinating Ir(III) complex into the as-prepared Fe/ZIF-8. The preparation procedures avoid high-temperature and pyrolysis which endue Fe/Zn/Ir nanocomposite with high stability and can be scaled up. Once Fe/Zn/Ir TAzyme catalyzes the substrate TMB to produce blue oxidized TMB (oxTMB), its luminescence is quenched by the generated oxTMB. Ascribed to its high POD-like activity and interesting luminescence property, a dual-mode sensing platform for the detection of melatonin (MT) is fabricated. In the presence of increasing concentrations of MT, the absorbance of the detection system declines, while the emission of the detection system grows. The detection platform exhibits the limits of detection (LODs) in colorimetric and luminescence detections are 8.9 nM and 8.8 nM, respectively, which can mutually validate the assay results. More importantly, Fe/Zn/Ir TAzyme has been fabricated into test swabs to monitor MT in the way of portable and naked-eye detection. This double-role TAzyme provides new conceptions for researchers to explore novel and highly efficient nanozymes in future. [ABSTRACT FROM AUTHOR]

[Display omitted] • The significance of the nature of Cu-Zn synergy for methanol synthesis was demonstrated. • The challenges of identification of the active Zn site, either Zn0 or Znδ+, was addressed and explored. • Recent advances by in situ microscopy, spectroscopy and surface site titration were summarized and discussed. • The understanding of the reaction mechanism via theoretical modeling and simulations was discussed. • The critical role of interfacial sites with oxygen defects in methanol synthesis was emphasized. Copper-zinc-alumina (Cu/ZnO/Al 2 O 3) has been utilized as the leading catalyst for industrial methanol synthesis via hydrogenation of CO and CO 2 for more than 50 years. Understanding the nature of active Zn sites at the atomic level is vital for gaining insight into the reaction mechanism and rational design of more efficient Cu/ZnO catalysts for methanol synthesis but remains greatly challenging and has been intensively debated for decades. In this mini-review, we first describe the fundamental insights obtained from well-defined model catalysts and then summarize the recent experimental evidence with respect to dynamic structural and electronic changes in the active Zn phase under realistic working conditions by in situ/operando microscopy/spectroscopy and surface site titration using probing molecules. In the following, we discuss the catalytic mechanism of diverse active structures by theoretical calculations and simulations. Therefore, the critical role of interfacial sites between metallic Cu and ZnO, especially those with oxygen defects, in methanol synthesis via CO 2 hydrogenation is emphasized. Finally, we discuss the technical challenges and perspectives in understanding the origins of this Cu-ZnO synergy and rational design of next-generation Cu-based methanol synthesis catalysts. [ABSTRACT FROM AUTHOR]

The current study was indented towards the evaluation of synergism of spent aluminum hydroxide nanoparticle (AHNP) adsorbent derived catalysts in the degradation of pine (Pinus roxburghii) needles through kinetics and thermodynamics analysis. Distinct kinetic (such as activation energy and pre-exponential factors) and thermodynamic (such as entropy, enthalpy, and Gibbs free energy) parameters were estimated through isoconversional (OFA and KAS) models. The study also aimed to envisage the reaction mechanism for all the distinct processes via Criado z master plots. Results illustrated the significant impact of all the different AHNP-derived catalysts in easing up the biomass degradation process. The KAS method evaluated the average activation energy for non-catalytic degradation as 130.01 kJ/mol, while the values changed to 120.95, 121.69, 125.99, 148.47 and 127.37 kJ/mol for Ni/AO, Fe/AO, Cu/AO, Zn/AO and Mo/AO catalyzed degradation, respectively. Amongst all, nickel (Ni/AO) and iron-doped (Fe/AO) catalysts brought the highest reduction in activation energy owing to the provision of strong acidic sites, high specific surface area, and better metal dispersion; subsequently leading to the increased rate of molecular scission and cracking reactions. Values of pre-exponential factor and thermodynamic parameter also displayed the positive impact of catalysts in terms of lowering down the molecular collisions, enthalpy, and disorderness of the system. Furthermore, artificial neural network (ANN) was also employed for the prediction of the biomass degradation where high regression (∼0.99) as well as low mean squared error (<10−5) illustrated the accurate prediction of complex biomass degradation by the ANN technique. Thus, the waste AHNP-derived catalysts have significant potential to be employed for the catalytic pyrolysis of pine needles together with aiding the cost-competitiveness, environmental sustainability, and renewability of the process. [Display omitted] • Spent adsorbent based catalysts significantly impacted the pyrolysis kinetics. • KAS method evaluated the non-catalytic pyrolysis activation energy as 130.01 kJ/mol. • Ni and Fe doped catalysts reduced it to 120.95 and 121.69 kJ/mol, respectively. • ANN accurately predicted the biomass degradation with high R2 (∼0.99) and low MSE (<10−5). • The study will assist in reactor designing and process scale-up. [ABSTRACT FROM AUTHOR]

• Highly selective synthesis of ethyl pyruvate was realized in liquid-phase. • The conversion of ethyl lactate to ethyl pyruvate using O2 as oxidant was realized under 90 oC temperature. • The yield of ethyl pyruvate reached up to 92.6 % when ethyl lactate was fully converted. • The optimized SBA-15/Zn(10)/Ni(15) catalyst owned high surface area (630.01 m2 g −1) and enhanced charge separation efficiency. • SBA-15/Zn(10)/Ni(15) serves as recyclable heterogeneous catalyst without compromising the activity. The solid-state catalyst-mediated oxidation of alkyl lactate produced from biomass to alkyl pyruvate is an intriguing approach to manufacture valuable resources compounds. In this study, several types of SBA-15/Zn/Ni catalysts containing different nickel loadings have been developed and used in a molecular oxygen environment to oxidize ethyl lactate (EL) compound to ethyl pyruvate (EP). The aforementioned catalyst was comprehensively characterised by employing XRD, ICP, FTIR, N 2 physisorption, NH 3 -TPD, HR-SEM and HR-TEM. As more of nickel was loaded onto the Ni/Zn/SBA-15 catalyst, the EL conversion improved, but the selectivity of EP consistently exceeded greater than 95 %, regardless of the 15 % nickel loading. Assuming maximum conditions for the reaction (90 °C, 2 h in O 2) over the Ni/Zn/SBA-15 catalyst, the selectivity of 99.5 % for EP and a conversion of 97.7 % for EL were achieved. A selectivity of 99.5 % for EP and a conversion of 97.7 % for EL were achieved. The catalytic combination of SBA-15 and Zn/Ni exhibited a significant reducing capacity due to the significant connection between both of them, as demonstrated by the NH 3 -TPD data. [Display omitted] [ABSTRACT FROM AUTHOR]

• Water treatment improves the crystallinity and surface area of ZnGA. • The cyanide-modification of water-activated zinc glutarate (ZnGA) enhances the catalytic performance. • High molecular weight poly(propylene carbonate) was synthesized by ZnGA/DMC catalysts. Zinc glutarate (ZnGA) is a prominent catalyst for the production of CO 2 -based poly(propylene carbonate). The original catalysts, ZnO-GA (Cat 1) and ZnAc 2 -GA (Cat 3), were prepared using ZnO and ZnAc 2 as Zn sources, respectively. ZnO-GA-H 2 O (Cat 2) and ZnAc 2 -GA-H 2 O (Cat 4) were prepared by water treatment of Cat 1 and Cat 3 , respectively. After water treatment, both Cat 2 and Cat 4 showed enhanced performance for copolymerization of CO 2 and propylene oxide. The characterizations demonstrated that H 2 O is a critical component that not only improves the crystallinity and external surface area of ZnGA, but also increases the number of surface Zn-OH groups. By adding a portion of cyanide, further modification on Cat 4 resulted in a group of ZnAc 2 -GA-H 2 O/DMC catalysts (m-Cat 4). The polymerization reached a high yield of 1729 g poly/g Cat and a selectivity of 98.7 % at molar ratio of DMC/ZnGA = 1: 10 (t = 24 h; T = 70 °C; P = 4 MPa). The modified ZnGA/DMC catalyst exhibited remarkable yield and selectivity for the copolymerization of CO 2 and propylene oxide to produce high molecular weight alternating copolymers (2.3 × 105 g/mol). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Versatile Synthesis of Homoallylamines: This study presents efficient methods for the synthesis of homoallylamines, which are valuable precursors in the formation of bioactive N -heterocycles, such as pyrrolidines and β-lactams. • Regioselective Allylation: The research demonstrates the regioselective allylation of aldimines with allyl metal reagents under sonochemical Barbier-type reaction conditions and AlCl3 catalysis, achieving both α-adduct and γ-adduct formations. • High Regio- and Stereoselectivity: Optimized reaction conditions lead to high regio- and stereoselectivity, with ultrasonic-mediated conditions favoring α-adducts and AlCl3 catalysis promoting γ-adducts. • Substrate Scope and Functional Group Compatibility: The methods exhibit broad substrate scope, accommodating various aldimines with different substituents, including phenyl, tosyl, and heteroaromatic groups, yielding products in moderate to good yields with excellent regioselectivity. • Mechanistic Insights: Proposed mechanisms for both the sonochemical and AlCl3-catalyzed processes explain the observed regioselectivity and diastereoselectivity, highlighting the role of zinc activation and Lewis acid catalysis in facilitating the reactions. The allylation reaction of aldimines with allyl metal reagents is an important synthetic method for the preparation of homoallylamines. Therefore, we wish to report a highly regioselective and stereoselective allylation reaction under sonochemical Barbier-type reaction conditions. The high yields of regioselective α-adducts were achieved by reacting cinnamyl bromide, zinc, 1,2-dibromoethane, and aldimine in THF under sonochemical Barbier-type conditions. Highly regioselective and stereoselective allylation reactions were also achieved under Lewis acid-promoted Barbier-type reaction conditions. [ABSTRACT FROM AUTHOR]

The synthesis of value-added aromatic products, such as para-ethyl-toluene (PetT), from the greenhouse gas carbon dioxide (CO 2) and renewable hydrogen (H 2) is greatly desired. However, considerable challenges arise due to complex kinetics and difficulties in arranging multiple active components. Herein, we present a strategy for the selective synthesis of PetT via CO 2 hydrogenation in the presence of ethylbenzene via tandem reactions over a composite catalyst comprising Zn-Zr binary oxide and a modified crystal-stacking HZSM-5 zeolite, achieving over 70% PetT selectivity in the ethyl-toluene (ET) isomers (∼80% in the C 5+ hydrocarbons). State-of-the-art (quasi) in situ characterizations and corresponding theoretical calculations confirmed the designed reaction route involving stepwise activation of CO 2 to methoxy species and enhanced aromatic cycles for the formation of C–C bonds. And precisely controlled transfer and transformation of intermediate methoxy species contribute to the promoted performance in the selective synthesis of PetT. [Display omitted] • 80% ET containing 70% PetT was obtained over an oxide-zeolite composite catalyst. • Stepwise CO 2 activation and enhanced aromatic cycle afforded the tandem reactions. • Methoxy transferring makes great effect on the efficiency of tandem processes. • Key role of surface methoxy species is unveiled by experimental and DFT results. • Increasing components intimacy and zeolite acidity help increase performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis and characterization of two Schiff base complexes using microwave-assisted method. • Cu(II)complex showed highest activity in DNA binding/cleavage activity. • Antioxidant activities of the complexes indicated that Cu(II) is very good antioxidant. • Cu(II)complex exhibited better cytotoxicity activity. • Zn(II)complex showed good activity as catalyst in MCRs. Two mononuclear Cu(II) and Zn(II) based complexes were synthesized via microwave-assisted method utilizing Schiff base ligand based on 3,5-di-tertbutylsalicylaldehyde. The compounds were characterized using elemental and spectroscopic analysis methods. The ligand posed as an ON-donor ligand, confirmed by spectrum analysis in the complexes. A geometry optimization analysis was also performed using density functional theory to obtain the geometry, stability, and electronic properties of the synthesized compounds. CuL1 has a distorted square planar geometry, whereas ZnL1 has a distorted tetrahedral geometry. Fluorescence and absorbance spectroscopy were utilized to explore the interaction properties of calf thymus-deoxyribonucleic acid (CT-DNA) with the complexes. The CuL1 and ZnL1 are highly sensitive to DNA binding, with binding constant (K b) in the range of 105 M−1, representing substantial interaction with CT-DNA, combining intercalation and electrostatic interactions. The Stern-Volmer constant (K sv) obtained from the fluorescence spectroscopy method varied from 3.31 x 104 to 8.42 x 104 M−1, indicating moderate DNA binding. Circular dichroism spectroscopy confirmed the presence of intercalative binding among the DNA and the complexes. The in-vitro DNA cleavage activity revealed that complexes could efficiently break the supercoiled plasmid DNA without using any external agents. The complex CuL1 induced significant cytotoxicity for Dalton's lymphoma cancer cell lines, having IC 50 values of 18.96 ± 0.021 μM. The antioxidant activity of the compounds was also studied, confirming CuL1 to be the most active antioxidant with IC 50 = 399.27 µM. A molecular docking simulation was also conducted to comprehend the compounds' interaction mechanism with CT-DNA (1BNA) and cancer cells (BCL-family proteins). Furthermore, the catalytic activity of the zinc metal complex was assessed for multi-component reactions involving substituted benzaldehydes, malononitrile, and resorcinol. [ABSTRACT FROM AUTHOR]

The development of heterogeneous base catalyst with acid resistance has become a major topic in the current research on the biodiesel production process. Halloysite nanotubes (HNTs) is supported with bimetallic of calcium and zinc for modification and labeled as HNTs-Ca/Zn to show both the acid and base characteristics. Further, this supported catalyst is used to produce biodiesel from the acidulated palm oil through catalyzing transesterification in one-step in this study. The HNTs-Ca/Zn catalyst, synthesized by the impregnation method, is characterized by TG-DTG, XRD, XPS, TEM, SEM-EDX, nitrogen adsorption-desorption, CO 2 /NH 3 -TPD, FTIR and Raman. The capability of the HNTs-Ca/Zn catalyst in catalyzing transesterification is investigated, where the maximum yield of 95.22% is achieved with the molar ratio of Zn to Ca of 1.5. The advantage of HNTs-Ca/Zn1.5 catalyst is prominent when the transesterification source oil is acidulated, where the biodiesel yield of 92.66% is obtained even at the acid value of 26.02 mg KOH g−1. Besides, reusability of the catalyst is acceptable, where the yield of 77.91% is maintained after the fourth reused cycle. Further, the Genetic Algorithm-Back Propagation (GA-BP) neural network is used to train and predict the transesterification parameters of the reaction temperature, catalyst amount and methanol to oil molar ratio. The prediction of the biodiesel yield is reasonable. At the predicted reaction parameters of 158 °C, catalyst amount of 7.1 wt.% and methanol to oil molar ratio of 15.5, the predicted biodiesel yield is 98.71%, where the experimental verification value is 98.60%. Therefore, the HNTs-Ca/Zn catalyst is considered to demonstrate exceptional catalytic performance and recyclability, offering the potential for biodiesel production. [Display omitted] • HNTs-Ca/Zn acid-base bifunctional catalysts are produced for biodiesel production. • The HNTs-Ca/Zn1.5 catalyst performs excellent acid resistance under 26.02 mg KOH g−1. • Transesterification parameters are optimized by the GA-BP neural network. • The maximum biodiesel yield of 98.60% is obtained under the optimum conditions. [ABSTRACT FROM AUTHOR]

• Zn/Ag/ZnWO 4 is synthesized using an electrochemical approach assisted by CTAB. • Photocatalytic degradation of MG dye is assessed under visible-light conditions. • Zn/Ag/ZnWO 4 shows effective charge separation through a Z-scheme mechanism. • Zn/Ag/ZnWO 4 can act as a sustainable catalyst for wastewater purification. This study presents the synthesis of surface-decorated CTAB-capped ZnO nanoparticles doped with Ag/ZnWO 4 through a surfactant-assisted electrochemical synthesis approach. The development of surface-decorated composites is of considerable interest for enhancing photocatalytic efficiency. We report the synthesis of pristine, binary, and surface-decorated ZnO catalysts, specifically Zn, Zn/Ag, Zn/ZnWO 4 , and Zn/Ag/ZnWO 4. Various methods for physicochemical characterization have been utilized to verify the catalysts' structural, optical, and morphological properties. The results demonstrate the successful surfactant capping and metal doping. The synthesized nanoparticles have been tested for their photocatalytic performance against Malachite Green, an environmentally harmful organic dye, across various reaction conditions. Scavenger studies reveal that the photodegradation process is primarily driven by superoxide and hydroxyl radicals and, to a lesser extent, by photogenerated holes. The decrease in electron-hole pair recombination in the Zn/Ag/ZnWO 4 photocatalyst results in an enhanced degradation of Malachite Green when exposed to visible light. [Display omitted] [ABSTRACT FROM AUTHOR]

• A potential-induced self-reconstruction process was proposed for the synthesis of single-atomic Ru sites anchored on Co(OH) 2 ; • The single-atomic Ru sites reduced the overpotential for nitrate reduction and improved the NH 3 yield; • The single-atomic Ru sites facilitate the thermodynamic-determining step of *NH 2 -to-*NH 3 thus promoting the overall NO 3 −-to-NH 3 conversion. Conversion of NO 3 −-to-NH 3 via the electrocatalytic nitrate reduction reaction (NO 3 -RR) is an emerging strategy for ammonia production and storage of "green hydrogen", but is limited by the dissatisfactory activity and selectivity. In this study, we discovered that cobalt carbonate hydroxide (Co 2 (OH) 2 CO 3) underwent a potential-induced self-reconstruction to cobalt hydroxide (Co(OH) 2) during NO 3 -RR. The incorporation of Ru into Co 2 (OH) 2 CO 3 expedited the aforementioned self-reconstruction process and resulted in the formation of Ru single-atomic sites (Ru SASs) anchored on Co(OH) 2 nanosheets. This structure is reported as a highly efficient electrocatalyst for NO 3 −-to-NH 3 conversion and exhibits exceptional electrochemical performance in zinc-NO 3 − batteries. Theoretical analysis revealed that the conversion of NO 3 −-to-NH 3 occurred on Ru SASs through an N-end pathway with *NO as a characteristic intermediate. Furthermore, Ru SASs facilitated the thermodynamic-determining step of *NH 2 -to-*NH 3 , thus promoting the overall NO 3 −-to-NH 3 conversion process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tailoring the crystal facet of electrocatalyst for syngas production. • HFGDEs provide sufficient CO 2 supply and improved triple-phase interfaces. • Syngas selectivity over 90 % and achieved a production rate of 1328.6 µmol/h∙cm2. • This strategy can be versatile by loading other nanostructured electrocatalysts. Electrochemical reduction of CO 2 (CO 2 RR) in aqueous electrolytes not only relies on advanced gas diffusion electrodes (GDEs) to improve CO 2 mass transportation but also efficient electrocatalysts to produce specific products. Herein, to produce syngas (CO and H 2 mixture), a facet-orientated zinc nanosheet catalyst was electrodeposited on the Cu hollow fiber GDE via a controllable facile surfactant-assisted method. The introduction of cationic surfactant cetyl trimethyl ammonium bromide (CTAB) could manipulate the nucleation and crystal growth of zinc ions around the GDE during the electrodeposition process, leading to controlled changes in the surface free energy and tuned zinc crystal growth orientation. Consequently, the ZncNS-HF with the largest ratio of Zn (1 0 1)/Zn (0 0 2), resulted in a high current density of 73.3 mA/cm2 and a high syngas production rate of 1328.6 µmol/h∙cm2 at applied potential −1.3 V (vs. RHE). This comes from the hierarchical structure of HFGDE, which provides sufficient CO 2 reaching the catalyst/electrolyte interface, and the well-connected zinc nanosheets contribute to a significant number of active sites for CO 2 RR. This is the first time to configure flow-through or gas-penetrated HFGDEs with zinc crystal facets controlled nanosheet catalysts for syngas production. This research demonstrates the high potential of nanoengineering catalysts for HFGDEs to achieve high production rates of syngas. [ABSTRACT FROM AUTHOR]

Iron-based single-atom catalysts (SACs) are considered to the most promising catalysts to replace Pt for efficient oxygen reduction reaction (ORR). However, the precise synthesis of high-performance SACs and the understanding of their ORR origin remain challenging. In this work, microporous nitrogen-doped carbon with abundant and accessible atomically dispersed N-coordinated Fe sites (Fe-N-C) is prepared by molecular-confined coupling pyrolysis strategy. The Fe-N-C exhibits excellent ORR activities in acid (E 1/2 of 0.78 V vs. RHE) and alkaline (E 1/2 of 0.91 V vs. RHE) electrolytes. When integrated into a rechargeable aqueous Zinc-air battery (ZAB), both large specific capacity (770 mAh g−1) and high peak power density (240 mW cm−2) are achieved. Remarkably, the as-prepared ZAB presents amazing charge-discharge cycle performance of 1600 h at the large current density, which is 52.5 times of that using Pt/C+RuO 2. Furthermore, all-solid-state ZAB delivers ultra-robust cycling stability even under bending. This work may advance a critical step towards the design of rational and controlled preparation of remarkable and ultra-stable catalysts. • Fe-N-C single-atom catalyst is prepared by molecular-confined coupling pyrolysis strategy. • The obtained Fe-N-C has a large SD mass of 2.24 × 1020 sites g−1. • Fe-N-C shows excellent ORR activities in both alkaline (E 1/2 : 0.91 V) and acid (E 1/2 : 0.78 V) electrolytes. • ZAB with Fe-N-C air cathode presents long-term charge/discharge cycle performance of 1600 h. • The solid-state ZAB delivers ultra-robust cycling stability and high energy efficiency. [ABSTRACT FROM AUTHOR]

Monocyclic aromatic hydrocarbons (MAHs) are important organic building blocks for the chemical industry, which can be produced by catalytic pyrolysis of biomass. The wide application of bamboo in Chinese industry generates a large amount of bamboo waste which can be utilized as the feedstock to produce MAHs. This study aimed to investigate the effect of bamboo age and bamboo part on the yield of the aromatics by using the Cr and Zn modified HZSM-5 as catalyst. The result showed that the incorporation of metals (Cr and Zn) enhanced the catalytic performance, and the incorporation of Zn was better than Cr. The highest MAHs content (38.67%) and total aromatic content (57.42%) were obtained with the catalyst of 3% Zn/HZSM-5 catalyst at temperature of 400 °C and duration time of 30 min. Younger age (1-year-old bamboo) and the outer skin of bamboo was better for the production of MAHs. This study provided a high value-added application approach for the waste Moso bamboo. • Catalytic pyrolysis of bamboo at different ages and from different parts was performed. • Bifunctional catalyst (Zn and Cr modified HZSM-5) was employed as catalyst. • Effect of pyrolysis temperature and duration time was studied. • 3-years old bamboo with the out-skin part produced highest yield of aroamtics. • 3% Zn/HZSM-5 was the best catalyst to yield aromatics at 400 °C for 30 min. [ABSTRACT FROM AUTHOR]

• Bifunctional catalysts resisted to FFAs were synthesised for biodiesel production. • The SrO-0.6 Zn catalyst prepared by sol-gel method showed the best performance. • Biodiesel yield of 91.99 % was achieved with addition of 11 wt.% oleic acid. • Biodiesel yield reached 60.26 % in the fifth reused cycle with satisfying reusability. • Adsorption of acid, alcohol and ester on the catalyst surface was analysed by DFT. The basic active sites are rendered inactive by the free fatty acids (FFAs) in the feedstock. The aim of this study was to maximize the use of cheap and readily available waste cooking oil (WCO) and Sr-Zn oxide catalyst (prepared by sol-gel method) for biodiesel production. The best performing catalyst with a molar ratio of ZnO to SrO of 0.6 gave a biodiesel yield of 91.99 % even with the addition of 11 wt.% oleic acid. The morphology, crystal size and acid-base value of the Sr-Zn oxide catalysts were determined using various characterization methods. The results showed that the total basicity and acidity of the Sr-Zn oxide catalysts was 0.402 mmol/g and 0.367 mmol/g, respectively. After Zn doping, the specific surface area increased from 0.28 m2 g−1 to 0.41 m2 g−1. The adsorption energy of acetic acid on the surface of Sr-Zn oxide was calculated to be the maximum of -268.9 kJ/mol based on the density functional theory. Zinc doping stimulated the C = O bond of acetic acid with the charges of 0.028 e. As a result, Sr-Zn oxide catalysts demonstrated acceptable activity and reusability, indicating bright futures for the heterogeneous catalyst-mediated manufacturing of biodiesel. [Display omitted] [ABSTRACT FROM AUTHOR]

Global warming has gotten worse recently as a result of significant CO 2 emissions, making the development of technologies to lower greenhouse gas emissions of CO 2 a necessity. Thermo-catalytic hydrogenation of CO 2 into methanol, methane, carbon monoxide and olefin is a promising technique to overcome this problem, as it not only uses CO 2 as feedstock but also yields valuable chemicals. Presently, most catalytic studies reported on the development of new catalysts to overcome the limitations of conventional catalysts. ZnO is one of the metal oxides that has been frequently utilized as a support or promoter catalyst in CO 2 hydrogenation for the production of high value-added chemicals. However, the preparation of ZnO influenced the morphology and structure design of the fabricated catalysts. Recently, the tremendous inverse catalyst design involving ZnO has also been reported. The involvement of ZnO in CO 2 hydrogenation is very important as it provides sufficient surface area for metal dispersion, oxygen vacancies for the generation of active sites, basic/acid properties for adsorption-desorption of molecules as well as stability for long-term usage in the reaction process. Therefore, in this review, ZnO-based catalysts used in CO 2 hydrogenation and strategies to design ZnO-based catalysts were highlighted. Then, the mechanism involving ZnO-based catalysts in CO 2 hydrogenation was summarized. Finally, challenges and the future of the ZnO-based catalysts are provided, emphasizing the great potential for the efficient synthesis of high value-added chemicals by CO 2 conversion. [Display omitted] • Zinc oxide-based catalysts for CO 2 hydrogenation are systematically reviewed. • Modification of ZnO morphology and interfaces enhanced the catalytic activity. • The roles of ZnO in CO 2 hydrogenation are emphasized. • The possible mechanism over modified ZnO-based catalysts are presented. [ABSTRACT FROM AUTHOR]