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Bimetallic Mn 99.3 Zn 0.7 -MOF-74 with the highest ratio of MnIII exhibited efficient performance for the direct oxidative carboxylation of olefins to cyclic carbonates under mild and solvent-free conditions using aqueous TBHP oxidant, and could be reused for 5 consecutive runs without significant loss in activity and structure. [Display omitted] • In the obtained bimetallic MnZn-MOF-74, the valance state distributions of Mn were regulated with different Zn amount. • High ratio of active MnIII as main oxidant centers and Lewis acid/base sites made Mn 99.3 Zn 0.7 -MOF-74 catalyst efficient. • On direct oxidative carboxylation of styrene, Mn 99.3 Zn 0.7 -MOF-74 provided 92% styrene conversion with 59.8% selectivity. • Mn 99.3 Zn 0.7 -MOF-74 presented great universality to various olefins substrates and could be reused consecutively 5 runs. Multi-functional MOF catalyst with oxidative- and acid- centers showed potential in olefins oxidative carboxylation to cyclic carbonates directly. In this work, a series of bimetallic MnZn-MOF-74 with different molar ratios of Mn and Zn were synthesized successfully through a one-pot facile method. Thoroughly characterization indicated that the existence of Zn regulated the valance state distribution of Mn in the obtained MnZn-MOF-74. Mn 99.3 Zn 0.7 -MOF-74 with the highest ratio of MnIII (61.3 %) performed the most efficient activity for olefin direct tandem oxidative carboxylation reaction using aqueous tert -butyl hydroperoxide oxidant under solvent-free condition of 90 °C, 1.0 MPa CO 2 and 4 h. Mn 99.3 Zn 0.7 -MOF-74 also showed satisfactory versatility and recyclability. Based on the experiments, a feasible mechanism was presented. Thanks to the high ratio of active MnIII as main oxidative center, the coordination unsaturated bimetal Mn and Zn as Lewis-acid sites, O2– of metal − O as Lewis-base sites and combined effect with Bu 4 NBr cocatalyst, Mn 99.3 Zn 0.7 -MOF-74 presented efficient performance for the direct synthesis of cyclic carbonates from olefins. The metal Zn in MOF can regulate the valance state distribution of Mn and result in efficient catalytic property, presenting a potential avenue for direct oxidative carboxylation reaction of olefins to cyclic carbonates synthesis. [ABSTRACT FROM AUTHOR]

The model precatalyst sp3- and sp2-N dinitrogen-coordinated zinc–heteroimidazole has been used as an efficient catalyst for the ring-opening polymerization of cyclic esters. Subsequent to our exceptional active 5,6,7-trihydroquinolin-8-amine-zinc catalysts for the ring-opening polymerization (ROP) of ε-caprolactone, various pyridine-fused cycloalkanones (ring size from five to eight) are developed for the correspondent fused amine–pyridine derivatives and their zinc–heteroimidazole chloride complexes Zn1–Zn8 (LZnCl2) bearing N-diphenylphosphinoethyl pendants. Activated with two equivalents of LiN(SiMe3)2, the title zinc complexes efficiently promote the ROP of L-lactide (L-LA) in situ; among them, Zn4/2Li(NSiMe3)2 catalyzed 500 equivalent L-LA at 80 °C with 92% conversion in 5 min (TOF: 5520 h−1). Under the same conditions, the catalytic efficiency for the ROP of rac-LA by Zn1–Zn8/2Li(NSiMe3)2 was slightly lower than that for L-LA (highest TOF: 4440 h−1). In both cases, cyclooctyl-fused pyridyl–zinc complexes exhibited higher activity than others, while the cycloheptyl-fused zinc complexes showed the lowest activity. The microstructure analysis of the polymers showed they possessed a linear structure capped with CH3O as major and cyclic structure as minor. In this work, all the ligands and zinc complexes were well characterized by 1H/13C/31P NMR, FT-IR spectroscopy as well as elemental analysis. [ABSTRACT FROM AUTHOR]

The Faraday efficiency of CO 2 electroreduction to CO catalyzed by metalloporphyrins (MTPP, M = Fe, Co, Cu, Zn and Ni) is linearly related to the reaction energy barrier of the first proton-coupled electron reduction. [Display omitted] • Five metalloporphyrins(MTPPs) with different metal centers are compared for CO 2 RR. • CO 2 RR mechanism on MTPPs are calculated by first-principles calculations. • CoTPP exhibits the best CO 2 RR activity and selectivity. • The results of theoretical calculation are well verified by experimental tests. • The linear correlation between the selectivity of CO and the key energy barrier is revealed. Metal-functionalized porphyrin-like graphene structures are promising electrocatalysts for carbon dioxide reduction reaction (CO 2 RR) as their metal centers can modulate activity. Yet, the role of metal center of metalloporphyrins (MTPPs) in CO 2 reaction activity is still lacking deep understanding. Here, CO 2 RR mechanism on MTPPs with five different metal centers (M = Fe, Co, Cu, Zn and Ni) are examined by first-principles calculations. The *COOH formation is the rate determined step on the five MTPP structures, and the CoTPP exhibits the best CO 2 RR activity while ZnTPP and NiTPP are the worst, which is also verified by our experiment. The CO 2 RR activity is controlled by adsorption states of intermediates (*CO, *COOH), i.e., chemisorption (e.g., on CoTPP) and physisorption (on ZnTPP and NiTPP) of intermediates will lead to good and poor activity, respectively. The deeper the d- band center of the porphyrin ring complexed metal atom, the weaker bonding of MTPP with CO and COOH. Theoretical calculations and experimental results indicate that MTPPs with Co and Fe centers lead to a reduction in the energy barriers for the two uphill reaction steps in the electrocatalytic CO 2 reduction process, thereby enhancing CO 2 reduction electrocatalytic activity. Faradaic efficiency of CO is correlated with the reaction energy barrier of the first proton-coupled electron reduction process, displaying a strong linear correlation. This work provides a fundamental understanding of MTPPs used as electrocatalysts for CO 2 RR. [ABSTRACT FROM AUTHOR]

In this study, Co/Ni‐NC catalyst with hetero‐diatomic Co/Ni active sites dispersed on nitrogen‐doped carbon matrix is synthesized via the controlled pyrolysis of ZIF‐8 containing Co2+ and Ni2+ compounds. Experimental characterizations and theoretical calculations reveal that Co and Ni are atomically and uniformly dispersed in pairs of CoN4‐NiN4 with an intersite distance ≈0.41 nm, and there is long‐range d–d coupling between Co and Ni with more electron delocalization for higher bifunctional activity. Besides, the in situ grown carbon nanotubes at the edges of the catalyst particles allow high electronic conductivity for electrocatalysis process. Electrochemical evaluations demonstrate the superior ORR and OER bifunctionality of Co/Ni‐NC catalyst with a narrow potential gap of only 0.691 V and long‐term durability, significantly prevailing over the single‐atom Co‐NC and Ni‐NC catalysts and the benchmark Pt/C and RuO2 catalysts. Co/Ni‐NC catalyzed Zn–air batteries achieve a high specific capacity of 771 mAh g−1 and a long continuous operation period up to 340 h with a small voltage gap of ≈0.65 V, also much superior to Pt/C‐RuO2. [ABSTRACT FROM AUTHOR]

This study is the first application of a PVDF-HFP-based polymer inclusion membrane incorporating the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as the base polymer and extractant for the extraction of bismuth(III), respectively. It is demonstrated that the PIM comprised of 60 wt% PVDF-HFP and 40 wt% D2EHPA is the most effective in the extraction of bismuth(III) from feed solution containing 20 mg L−1 bismuth(III) and 0.2 mol L−1 sulfate adjusted to pH 1.4. The extracted bismuth(III) ions are back-extracted quantitatively to the receiving solution containing 1 mol L−1 sulfuric acid. The stoichiometry experiments reveal that the Bi: D2EHPA ratio in the bismuth(III) extracted complex is 1:6, and D2EHPA is dimer. Moreover, it is shown that the studied PIM has high selectivity in the extraction of bismuth(III) over other interfering ions such as Mo(VI), Cr(III), Al(III), Fe(III), Ni(II), Zn(II), Cd(II), Co(II), Cu(II), and Mn(II). The interference of Fe(III) is also eliminated by masking with fluoride, leading finally to a nearly pure extraction of bismuth(III). [ABSTRACT FROM AUTHOR]

Le Chatelier's principle is a basic rule in textbook defining the correlations of reaction activities and specific system parameters (like concentrations), serving as the guideline for regulating chemical/catalytic systems. Here we report a model system breaking this constraint in O2 electroreduction in mixed dioxygen. We unravel the central role of creating single-zinc vacancies in a crystal structure that leads to enzyme-like binding of the catalyst with enhanced selectivity to O2, shifting the reaction pathway from Langmuir-Hinshelwood to an upgraded triple-phase Eley-Rideal mechanism. The model system shows minute activity alteration of H2O2 yields (25.89~24.99 mol gcat−1 h−1) and Faradaic efficiencies (92.5%~89.3%) in the O2 levels of 100%~21% at the current density of 50~300 mA cm−2, which apparently violate macroscopic Le Chatelier's reaction kinetics. A standalone prototype device is built for high-rate H2O2 production from atmospheric air, achieving the highest Faradaic efficiencies of 87.8% at 320 mA cm−2, overtaking the state-of-the-art catalysts and approaching the theoretical limit for direct air electrolysis (~345.8 mA cm−2). Further techno-economics analyses display the use of atmospheric air feedstock affording 21.7% better economics as comparison to high-purity O2, achieving the lowest H2O2 capital cost of 0.3 $ Kg−1. Given the recent surge of demonstrations on tailoring chemical/catalytic systems based on the Le Chatelier's principle, the present finding would have general implications, allowing for leveraging systems "beyond" this classical rule. The principle of Le Chatelier is a fundamental concept in textbooks, serving as a guiding principle for controlling chemical and catalytic systems. In this study, the authors present an oxygen electroreduction system based on a single zinc vacancy catalyst, which operates in a manner that extends "beyond" Le Chatelier's principle. [ABSTRACT FROM AUTHOR]

In this study, a magnetic catalyst of phosphotungstic acid salt (ZnHPMo12O40) was prepared by substitution of protons in H3PW12O40 with zinc metal cations as a recyclable catalyst. The structural and morphology of the prepared catalysts was investigated using Fourier transform infrared spectroscopy (FT-IR), differential thermal gravimetric analysis (TGA), BET surface analysis emission scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The prepared catalyst was successfully used as an efficient and recyclable catalyst for the synthesis of 4H-pyrans. The results showed that the magnetic zinc phosphotungstic acid catalyst exhibited good catalytic activity under optimum reaction conditions and the desired products were obtained in good to excellent yields. The good activity of the zinc salt of heteropoly acid catalyst was closely related to its high specific surface area, and the synergistic effects of Lewis and Brønsted acidity. The catalyst stability was good and it can be reused six times without significant loss activity in reaction. [ABSTRACT FROM AUTHOR]

Achieving selective hydrodeoxygenation of α, β-unsaturated carbonyl groups to alkenes poses a substantial challenge due to the presence of multiple functional groups. In this study, we develop a ZnNC-X catalyst (X represents the calcination temperature) that incorporates both Lewis acidic-basic sites and Zn-Nx sites to address this challenge. Among the catalyst variants, ZnNC-900 catalyst exhibits impressive selectivity for alkenes in the hydrodeoxygenation of α, β-unsaturated carbonyl compounds, achieving up to 94.8% selectivity. Through comprehensive mechanism investigations and catalyst characterization, we identify the Lewis acidic-basic sites as responsible for the selective hydrogenation of C=O bonds, while the Zn-Nx sites facilitate the subsequent selective hydrodeoxygenation step. Furthermore, ZnNC-900 catalyst displays broad applicability across a diverse range of unsaturated carbonyl compounds. These findings not only offer valuable insights into the design of effective catalysts for controlling alkene selectivity but also extend the scope of sustainable transformations in synthetic chemistry. The selective reduction of α, β-unsaturated carbonyls remains a challenge. Here the authors report a zinc-based catalyst for this reaction, converting α, β-unsaturated carbonyl compounds into unsaturated alcohols followed by hydrodeoxygenation to form alkenes. [ABSTRACT FROM AUTHOR]

Catalysts enriched in Zinc ferrite (ZFO) were synthesized using coprecipitation and hydrothermal methods. Mixtures of crystalline nanoparticles (ZFO and α-Fe2O3, several allotropic varieties of FeO) were characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM, SEM), N2 sorption, UV-visible spectrophotometry (UV-Vis) and X-ray photoelectron spectroscopy (XPS). After detailed characterizations, the catalytic performance of the solids (1 g/L) in the degradation of amoxicillin (AMX) (10 mg/L) as an antibiotic pollutant in water was evaluated. In addition, we used air as the oxygen source and adjusted the pH to 5.0. Consequently, the catalysts obtained via the hydrothermal method HT-ZFO had a high activity (100% of AMX removal in less than 100 min when an LED (75 W) light was used) compared to a similar mixture of oxides with graphene HT-ZFO-GO (a longer time of 150 min) that was necessary for the complete degradation of AMX. Impregnation with an aqueous solution containing 80 mg of GO obtained using Hummer's method, reduced into RGO by an ultrasound treatment, enhances the initial reaction rate but is associated with a prolonged time for complete AMX removal (10 ppm in water) that we attribute to its spontaneous corrosion. [ABSTRACT FROM AUTHOR]

Environmental organo bentonite synthesis using curcumin-derived chemicals is used as catalyst support for zinc with a Zn-pillaring structure (Zn@CU/BEN). The obtained composite was assessed as an affordable, highly effective, and multifunctional photocatalyst for enhanced oxidation of ibuprofen (IBU) residuals in water supplies. The Zn@CU/BEN composite (0.4 g/L) displayed significant catalytic activities, resulting in the complete oxidation of IBU (25 mg/L) after 80 min. Then, the complete mineralization based on the full elimination of TOC content was recognized after 160 min, with significant indications about the formed intermediates. The identified intermediates, together with the identification of hydroxyl radicals as the essential oxidizing agent, declared an oxidation pathway of IBU over Zn@CU/BEN that involved three steps: hydroxylation, decarboxylation/demethylation, and ring-opening processes. The toxic properties of raw pollutants as well as the oxidizing product at different durations were assessed based on the cell viability results of kidney (HEK293T) and liver (HepG2) cell lines. The partially oxidized sample in the initial duration displayed a higher toxicity impact than the raw IBU. However, the treated sample after 160 min reflected high biosafety and non-toxic properties (cell viability > 97%). The synergetic impact of bentonite and bentonite organo-modified by curcumin extract reflects enhancements in the adsorption as well as the oxidation performance of pillared zinc as a catalyst. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

The development of efficient and low‐cost bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is imperative but remains challenging in rechargeable zinc–air batteries. Herein, a metal oxidation‐assisted approach is developed for the facile synthesis of a highly efficient bifunctional catalyst (Co@NC@LDHs) which is composed of layered double hydroxides (LDHs) nanosheets in situ vertically grown on the surface of hollow carbon nanoframes encapsulating Co nanoparticles (Co@NC). Specifically, the vertical LDHs distributing on the carbon surface ensure the maximized number of accessible active sites and the interaction between LDHs with the carbon matrix. The hierarchically structured bifunctional Co@NC@LDHs display an overpotential of 0.33 V at 10 mA cm−2 for OER and a half‐wave potential of 0.88 V for ORR. The potential gap (ΔE) of Co@NC@LDHs is calculated to be 0.68 V, outperforming the mixed Pt/C + RuO2 catalysts (ΔE = 0.77 V), manifesting its superior bifunctional electrocatalysis performance. Moreover, the Zn–air batteries based on Co@NC@LDHs electrocatalyst exhibit a high peak power density (185.2 mW cm−2) and excellent durability (5.0 mA cm−2 over 500 h). This work may provide a facile strategy for the fabrication of LDHs on carbon substrate, acting as efficient catalysts for broad energy‐related applications. [ABSTRACT FROM AUTHOR]

A series of ZnO-doped nitrogen-carbon materials (xZnO-N-C) with ZnO contents of 5–40% are prepared by a vacuum curing–carbonization strategy using polyamide-imide as the N-C source and zinc nitrate as the metal source for propane dehydrogenation (PDH). 20ZnO-N-C exhibits outstanding initial activity (propane conversion of 35.2% and propene yield of 24.6%) and a relatively low deactivation rate (0.071 h−1) at 600 °C. The results of detailed characterization show that small ZnO nanoparticles (5.5 nm) with high dispersion on the catalyst can be obtained by adjusting the ZnO loading. Moreover, more nitrogen-based species, especially ZnNx species, are formed on 20ZnO-N-C in comparison with 20ZnO-N-C-air prepared via curing carbonization without vacuum, which may contribute to the higher product selectivity and catalytic stability of 20ZnO-N-C. The active sites for the PDH reaction on the catalyst system are proposed to be C=O species and Zn2+ species. Moreover, the carbon deposition and the aggregation of ZnO nanoparticles are the causes of activity loss on this catalyst system. [ABSTRACT FROM AUTHOR]

In this study, we report the design, synthesis, and catalytic application of the novel nitrogen-rich Zn(II) MOF [Zn2(μ3-1κN,2κN′,3κO-HL)2(DMF)2]n·nH2O (HL2− = 4-((4-(1H-tetrazol-5-yl)phenyl)carbamoyl)benzoate), denoted as ZnMOF, for the efficient conversion of carbon dioxide (CO2) to cyclic carbonates via cycloaddition with epoxides. It was synthesised from a tetrazole appended amide-functionalised pro-ligand (H3L) and Zn(NO3)2·6H2O under hydrothermal conditions. The synthesised material was characterised namely by elemental analysis, infrared spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction analyses. The catalytic potential of ZnMOF was investigated in the CO2 cycloaddition reaction with various epoxides, with conversions ranging from 17% to 99%. The catalyst retained its activity across multiple reaction cycles, demonstrating its stability and reusability. The influence of co-catalysts on the reaction was explored, with tetrabutylammonium bromide (TBABr) emerging as the most effective one. A plausible reaction mechanism is proposed. [ABSTRACT FROM AUTHOR]

In this study, we have successfully synthesized a high surface area of activated carbons (ACs) from cocoa pod husk (CPH) by using a combination of hydrothermal carbonization (HTC) and chemical activation in the presence of ZnCl2 as both of catalyst as well as activating agent. During HTC, the effect of HTC temperature (200 and 225℃) and ZnCl2 to biomass mass ratio (1:1, 2:1, 3:1) as a catalyst to the characteristics of the obtained hydrochar (HC) and ACs were investigated. The obtained hydrochar (HCs) was then processed by using ZnCl2 chemical activation with a fixed HC to ZnCl2 mass ratio of 1:4 and the mixture was pyrolyzed at 600 ℃ for 1 h under an inert atmosphere. The results showed that the addition of catalyst during HTC presented different AC morphology, where the carbon samples were decorated with carbon microspheres. An increase of surface area was observed, where the ACs synthesized from catalyzed HC at biomass to ZnCl2 ratio of 1:3 at temperature 200 ℃ gave a higher surface area of 1954 m2/g compared to that of without catalyst (1165 m²/g). The catalysis effect was more profound at the HTC temperature of 200 ℃ compared to 225 ℃, as reflected in the significant increase of AC surface area. The addition of a catalyst creates ACs with narrow pore distribution compared to that of synthesized in the absence of a catalyst. It was also observed that the ACs from catalyzed hydrochar possessed higher oxygenated functional groups (OFG) than those without catalysts. [ABSTRACT FROM AUTHOR]

A zinc (Zn)‐based single‐atom catalyst (SAC) is recently reported as an active Fenton‐like catalyst; however, the low Zn loading greatly restricts its catalytic activity. Herein, a molecule‐confined pyrolysis method is demonstrated to evidently increase the Zn loading to 11.54 wt.% for a Zn SAC (ZnSA‐N‐C) containing a mixture of Zn−N4 and Zn−N3 coordination structures. The latter unsaturated Zn−N3 sites promote electron delocalization to lower the average valence state of Zn in the mix‐coordinated Zn−Nx moiety conducive to interaction of ZnSA‐N‐C with peroxydisulfate (PDS). A speedy Fenton‐like catalysis is thus realized by the high‐loading and low‐valence ZnSA‐N‐C for PDS activation with a specific activity up to 0.11 min L−1 m−2, outstripping most Fenton‐like SACs. Experimental results reveal that the formation of ZnSA‐N‐C−PDS* complex owing to the strong affinity of ZnSA‐N‐C to PDS empowers intense direct electron transfer from the electron‐rich pollutant toward this complex, dominating the rapid bisphenol A (BPA) elimination. The electron transfer pathway benefits the desirable environmental robustness of the ZnSA‐N‐C/PDS system for actual water decontamination. This work represents a new class of efficient and durable Fenton‐like SACs for potential practical environmental applications. [ABSTRACT FROM AUTHOR]

In this work, thioether-amide ligands featuring a combination of hard amide groups with soft donor groups have been employed to develop new zinc catalysts for the ring-opening polymerization of cyclic esters. All complexes were prepared in high yields through alkane elimination reactions with diethyl zinc and characterized using nuclear magnetic resonance (NMR) spectroscopy. Density functional theory (DFT) characterization provided insight into the parameters that influence catalytic activity, such as steric hindrance at the metal center, Lewis acidity and electronic density of thioether-amide ligands. In the presence of one equivalent of isopropanol, all complexes were active in the ring-opening polymerization of rac-β-butyrolactone. Quantitative conversion of 100 monomer equivalents was achieved within 1 h at 80 °C in a toluene solution. Number-average molecular weights increased linearly with monomer conversion; the values were in optimal agreement with those expected, and polydispersity index values were narrow and relatively constant throughout the course of polymerization. The most active complex was also effective in the ring-opening polymerization of ε-caprolactone and L-lactide. To propose a reliable reaction path, DFT calculations were undertaken. In the first step of the reaction, the acidic proton of the alcohol is transferred to the basic nitrogen atom of the amide ligand coordinated to the zinc ion. This leads to the alcoholysis of the Zn-N bond and the formation of an alcoholate derivative that starts the polymerization. In subsequent steps, the reaction follows the classical coordination–insertion mechanism. [ABSTRACT FROM AUTHOR]

The aim of this work was to fabricate a new heterogeneous catalyst as zinc ferrite (ZF) supported on gamma-alumina (γ-Al2O3) for the conversion of cyclic ethers to the corresponding, more valuable lactones, using a solvent-free method and O2 as an oxidant. Hence, the ZF@γ-Al2O3 catalyst was prepared using a deposition–coprecipitation method, then characterized using TEM, SEM, EDS, TGA, FTIR, XRD, ICP, XPS, and BET surface area, and further applied for aerobic oxidation of cyclic ethers. The structural analysis indicated spherical, uniform ZF particles of 24 nm dispersed on the alumina support. Importantly, the incorporation of ZF into the support influenced its texture, i.e., the surface area and pore size were reduced while the pore diameter was increased. The product identification indicated lactone compound as the major product for saturated cyclic ether oxidation. For THF as a model reaction, it was found that the supported catalyst was 3.2 times more potent towards the oxidation of cyclic ethers than the unsupported one. Furthermore, the low reactivity of the six-membered ethers can be tackled by optimizing the oxidant pressure and the reaction time. In the case of unsaturated ethers, deep oxidation and polymerization reactions were competitive oxidations. Furthermore, it was found that the supported catalyst maintained good stability and catalytic activity, even after four cycles. [ABSTRACT FROM AUTHOR]

Herein, we report the wet-chemical synthesis of a ferromagnetic nickel-doped ZnO (Zn 1-x Ni x O) nanocatalyst as a novel and visible-light-driven photocatalyst. Through X-ray diffraction, UV/Vis absorption, electronic studies, and current-voltage experiments, the effect of the ferromagnetic nickel dopant on the structural, optical, morphological, and electrical properties of the synthesized Zn 1-x Ni x O nanocatalyst was studied. The Ni-doping introduced the structural variation in the Zn 1-x Ni x O nanocatalyst, exhibiting a visible light-triggered optical band gap of 2.96 eV and an excellent current conductivity of 6.3 × 10−4 Sm−1. Moreover, the synthesis of the Zn 1-x Ni x O catalyst at the nanoscale enhanced its surface energy, showing a robust affinity to stick with the dye and pathogenic microbes. The synergistic effects of all the mentioned features enable our Zn 1-x Ni x O nanocatalyst to efficiently generate and transport reactive oxygen species (ROS) under visible light illumination. Regarding antibacterial action, the as-synthesized Zn 1-x Ni x O nanocatalyst showed 1.7% higher activity against E. coli than that of the drug Ciprofloxacin. In addition, doped nanocatalysts mineralize almost 97% of the Allura red dye in just 80 min with a constant rate value of 0.036 min−1. The impedance study and post-application XRD proposed that our Zn 1-x Ni x O nanocatalyst has good conductivity and structural stability. Applications studies show the unusual photocatalytic activity of as-synthesized Zn 1-x Ni x O nanocatalysts, which makes it a suitable candidate for industrial discharge treatment applications at the expense of solar light. [Display omitted] [ABSTRACT FROM AUTHOR]

Here, we report a Na-promoted FeCu-based catalyst with excellent liquid hydrocarbon selectivity and catalytic activity. The physiochemical properties of the catalysts were comprehensively characterized by various characterization techniques. The characterization results indicate that the catalytic performance of the catalysts was closely related to the nature of the metal promoters. The Na-AlFeCu possessed the highest CO2 conversion due to enhanced CO2 adsorption of the catalysts by the introduction of Al species. The introduction of excess Mg promoter led to a strong methanation activity of the catalyst. Mn and Ga promoters exhibited high selectivity for light hydrocarbons due to their inhibition of iron carbides generation, resulting in a lack of chain growth capacity. The Na-ZnFeCu catalyst exhibited the optimal C5+ yield, owing to the fact that the Zn promoter improved the catalytic activity and liquid hydrocarbon selectivity by modulating the surface CO2 adsorption and carbide content. Carbon dioxide (CO2) hydrogenation to liquid fuel is considered a method for the utilization and conversion of CO2, whereas satisfactory activity and selectivity remains a challenge. This method provides a new idea for the catalytic hydrogenation of CO2 and from there the preparation of high-value-added products. [ABSTRACT FROM AUTHOR]

[Display omitted] • γ -Al 2 O 3 -based catalysts with varying Zn contents are prepared for CF 4 hydrolysis. • γ -Al 2 O 3 chemisorbs H 2 O predominantly compared to CF 4 , giving limited activity. • Optimal Zn loading (Zn/Al = 0.1) selectively forms ZnAl 2 O 4 on the surface of γ -Al 2 O 3. • Zn enhances CF 4 adsorption and weakens H 2 O adsorption, mitigating H 2 O poisoning. • ZnAl 2 O 4 inhibits the phase transition of γ -Al 2 O 3 to α -Al 2 O 3 , improving stability. Perfluorocarbons (PFCs) such as CF 4 are extensively used as etchants and cleaning agents in semiconductor manufacturing. Because of their significant global warming potential, it is important to develop efficient technologies to decompose PFCs. In this study, we synthesized a series of Zn-promoted γ -Al 2 O 3 catalysts with varying Zn contents for CF 4 hydrolysis. Physical characterizations and kinetic studies indicated that the Lewis acid sites of unpromoted γ -Al 2 O 3 predominantly adsorb H 2 O compared to CF 4 under the reaction conditions, resulting in limited catalytic activity (H 2 O poisoning). As the Zn/Al molar ratio increased up to 0.1, nanocrystalline ZnAl 2 O 4 was selectively formed on the surface of γ -Al 2 O 3 crystallites, generating a core-shell-like structure. The Lewis acid sites on the ZnAl 2 O 4 surfaces exhibited enhanced CF 4 adsorption and weakened H 2 O adsorption compared to those on γ -Al 2 O 3 , thereby alleviating the detrimental effect of H 2 O poisoning. Consequently, despite the reduction in the total number of Lewis acid sites upon Zn addition, Zn-promoted γ -Al 2 O 3 catalysts exhibited significantly enhanced catalytic activity. Furthermore, the ZnAl 2 O 4 covering the γ -Al 2 O 3 crystallites inhibited their phase transition to α -Al 2 O 3 , improving catalytic stability. When the Zn content was increased excessively (Zn/Al > 0.1), bulk ZnAl 2 O 4 crystallites with low Lewis acidity were formed, resulting in a substantial loss of catalytic activity. [ABSTRACT FROM AUTHOR]

Enantiomerically pure (S)-1-phenylethan-1-amine has been applied in Mannich-type condensation between formaldehyde and naphthalenediols leading to the synthesis of chiral bis-dihydro[1,3]naphthoxazines in excellent yields. Salen-type structures have been synthesized, applying R,R- or S,S-cyclohexane-1,2-diamines in condensation with formaldehyde and naphthalene-2-ol. The obtained chiral imidazolidine derivatives of the type 1,1′-(((3a,7a)-hexahydro-1H-benzo[d]imidazole-1,3(2H)diyl)bis(methylene))bis(naphthalen-2-ol) were evaluated as pre-catalysts for the addition of diethyl zinc to aldehydes. The structures of the newly synthesized compounds were elucidated using 1D and 2D NMR experiments (COSY, HMBC, HSQS), elemental analysis, mass spectrometry (HRMS spectra) and single-crystal X-ray diffraction (SCXRD). The products were further characterized with powder X-ray diffraction (PXRD) and thermal analysis (DSC). [ABSTRACT FROM AUTHOR]

The need to recycle carbon-fibre-reinforced composite polymers (CFRP) has grown significantly to reduce the environmental impact generated by their production. To meet this need, thermoreversible epoxy matrices have been developed in recent years. This study investigates the performance of an epoxy vitrimer made by introducing a metal catalyst (Zn2+) and its carbon fibre composites, focusing on the healing capability of the system. The dynamic crosslinking networks endow vitrimers with interesting rheological behaviour; the capability of the formulated resin (AV-5) has been assessed by creep tests. The analysis showed increased molecular mobility above a topology freezing temperature (Tv). However, the reinforcement phase inhibits the flow capability, reducing the flow. The fracture behaviour of CFRP made with the vitrimeric resin has been investigated by Mode I and Mode II tests and compared with the conventional system. The repairability of the vitrimeric CFRP has been investigated by attempting to recover the delaminated samples, which yielded unsatisfactory results. Moreover, the healing efficiency of the modified epoxy composites has been assessed using the vitrimer as an adhesive layer. The joints were able to recover about 84% of the lap shear strength of the pristine system. [ABSTRACT FROM AUTHOR]

A series of mixed copper (II)—zinc oxide catalysts supported on unmodified and ceria-modified silica supports were synthesized using β-cyclodextrin as a template. The novelty of this work lies in the use of cyclosextrins for the template synthesis of catalyst supports. The obtained samples were analyzed by XRD, SEM-EDX, low-temperature nitrogen physisorption, XPS, and EPR. The magnetic properties of the catalysts were also measured. The thermal decomposition of precursors was analyzed by TGA combined with mass-spectrometric analysis of the evolved gases. The effects of the support pore size, the nature of the active phase and its loading, as well as the sequence of component deposition on the catalyst performance in the CO2 conversion to methanol were studied. The catalysts with cerium added at the gelation stage demonstrated the best performance. The selectivity of these samples reaches values of more than 90% over a fairly ide temperature range, with the productivity reaching 480 g/kg cat·h at 300 °C. [ABSTRACT FROM AUTHOR]

Currently, catalytic pyrolysis has become a versatile and highly useful technology in the treatment of different plastic wastes. Thus, the development of selective catalysts to carry out cracking reactions and obtain a greater fraction of the desired products is essential. This study focuses on the synthesis of monometallic (Ni) and bimetallic (Ni-Zn) catalysts supported on ZSM-5 zeolite using an impregnation and co-impregnation method, respectively. The obtained catalysts were characterized by FTIR spectroscopy, N2 adsorption/desorption measurements, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS), temperature programmed NH3 desorption (TPD-NH3) and thermogravimetric analysis (TGA). In this way, a mixture of polystyrene and polypropylene recycled with a catalyst/plastic waste ratio of 1:500 was used for pyrolysis tests. The best results were obtained using the Ni-Zn/ZSM-5 catalyst, which included better impregnation, increased surface acidity, decreased dispersion and a shorter reaction time in the catalytic pyrolysis process. Under the optimized conditions, catalytic pyrolysis showed an excellent performance to generate hydrocarbons of greater industrial interest. [ABSTRACT FROM AUTHOR]

Zinc (Zn0) is a potent zero-valent metal (ZVM) capable of promoting both oxidation and reduction reactions in water. Similar to other ZVMs, Zn0's reactivity is rapidly retarded in water. This study aims to improve the activation of zinc particles (Zn0) by ultrasound in aqueous solutions buffered with 3-(N-morpholino)propanesulfonic acid (MOPS). Nitrite (NO2-) was chosen as a model compound to evaluate the effectiveness of ultrasonic zinc-MOPS treatment (US/Zn0/MOPS). Under similar experimental conditions, the maximum percent nitrite removal by Zn0 (8 g/L) in MOPS buffered solutions was around 45%, but it increased above 99% when ultrasound was introduced at 220.5 W. Results obtained from scanning electron microscopy-energy-dispersive X-ray spectroscopy and X-ray diffraction measurements have suggested that during US/Zn0/MOPS treatment, nitrite was reduced to nitrogen gas (N2) while Zn0 was oxidized to Zn2+ and/or Zn(OH)2. The results also indicated that the high nitrite reduction achieved by the combined method was due to a joint effect of both catalysts on zinc activation. [ABSTRACT FROM AUTHOR]

There is an urgent need to design and synthesize non-noble metal electrocatalysts (NNMEs) for the replacement of platinum-based electrocatalysts to enhance the sluggish oxygen reduction reaction (ORR) for Zn–air batteries and fuel cells. Herein, Fe-N,S-C materials were fabricated through two steps: first, reprecipitating hemin by adjusting the pH and, then, decorating it with melamine and cysteine in the presence of Zn2+. The resulting Fe-N,S-C-950 (Zn) was prepared after pyrolysis at 950 °C. Using this method, abundant iron-based active species with good dispersion were obtained. The fabrication of more micropores in Fe-N,S-C-950 (Zn) plays a positive role in the improvement of ORR activity. On comparison, Fe-N,S-C-950 (Zn) outperforms Fe-N,S-C-950 and Fe-N-C-950 (Zn) with respect to the ORR due to its larger specific surface area, porous structure, multiple iron-based active sites and N- and S-doped C. Fe-N,S-C-950 (Zn) achieves outstanding ORR performances, including a half-wave potential (E1/2) of 0.844 V and 0.715 V versus a reversible hydrogen electrode (RHE) in 0.1 M KOH and 0.1 M HClO4 solution, respectively. In addition, Fe-N,S-C-950 (Zn) shows an outstanding Zn–air battery performance with an open-circuit voltage (OCV) of 1.450 V and a peak power density of 121.9 mW cm−2, which is higher than that of 20 wt% Pt/C. As a result, the as-prepared electrocatalyst in this work shows the development of the Zn-assisted strategy combined with the assembly of porphyrins as NNMEs for the enhancement of the ORR in both alkaline and acidic solutions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Zn-In-O catalyst exhibits FE HCOO− (94.25 %) at −1.16 V RHE. • Rich interface effects improve the catalytic performance of Zn-In-O. • In 2 O 3 active center of Zn-In-O is protected from reducing by sacrificing ZnO phase. Electrochemical CO 2 reduction reaction (eCO 2 RR) is considered an efficient approach to produce value-added chemicals and fuels. In this paper, a series of MOF-derived composite catalysts with coexisting In 2 O 3 and ZnO are fabricated using a simple process for eCO 2 RR to produce formate. The Zn-In-O/800 catalyst achieves a formate Faradaic efficiency (FE HCOO−) of 94.25 % at −1.16 V vs. RHE, which can maintain over 89 % after 30 h in a stability test. The electrochemical evidence and density functional theory analysis show that the strong interface effect between In 2 O 3 and ZnO can enhance the CO 2 adsorption and activation, and promote the conversion of CO 2 to formate. In addition, the ZnO phase can protect In 2 O 3 , as the main active site, from being reduced to a certain extent for a long time under negative potential, which ensures the high stability of the composite catalyst. [ABSTRACT FROM AUTHOR]

Rechargeable zinc-air batteries (RZAB) have gained significant attention as potential energy storage devices due to their high energy density, cost-effectiveness, and to the fact that they are environmentally safe. However, the practical implementation of RZABs has been impeded by challenges such as sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), including poor cyclability. Herein, we report the preparation of cobalt- and nitrogen-doped porous carbon derived from phloroglucinol-formaldehyde polymer networks with 2-methyl imidazole and cobalt phthalocyanine as precursors for nitrogen and cobalt. The CoN-PC-2 catalyst prepared in this study exhibits commendable electrocatalytic activity for both ORR and OER, evidenced by a half-wave potential of 0.81 V and Ej=10 of 1.70 V. Moreover, the catalyst demonstrates outstanding performance in zinc-air batteries, achieving a peak power density of 158 mW cm−2 and displaying excellent stability during charge-discharge cycles. The findings from this study aim to provide valuable insights and guidelines for further research and the development of hierarchical micro-mesoporous carbon materials from polymer networks, facilitating their potential commercialisation and widespread deployment in energy storage applications. [ABSTRACT FROM AUTHOR]

The pyrolysis of corn stalk (CS) was carried out to investigate the effect of wet torrefaction (WT) pre-treatment and Zn/Ni-HZSM-5 on the production of bio-oil characteristics. The synergy between WT and the loaded metal catalyst was also analyzed. The oxygen content of the CS was reduced from 50.5% to 40.8% with WT, and hemicellulose was almost removed. WT pretreatment also significantly reduced the oxygenated compounds of bio-oil and increased the selectivity of phenols, aromatics, and anhydro-sugars. The addition of catalyst improved the deoxygenation, oligomerization, and aromatization during pyrolysis. The loading of Zn and Ni could optimize the pyrolysis reaction path and increased the relative content of monocyclic aromatics (MAHs) from 3.58% to 9.67% and 6.44% during the pyrolysis of CS-WT, respectively, and bimetallic catalyst further enhanced the relative content of MAHs to 11.1%. The relative content of aromatics below C9 was higher than other groups (14.8%). Thus, the WT pretreatment of raw materials and synergistic effect of catalysts can jointly optimize the biomass pyrolysis reaction. [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]

In this study, methyl orange, methylene blue, and amido black 10B were removed as target dyes using purified, synthetic, and purchased zinc ferrite as adsorbents and photocatalysts. The highest removal rates of amido black 10B by these adsorbents ranged from 81.62% to 88.33%. The removal rate of methyl orange was approximately 1%, and the removal rate of methylene blue was approximately 2%. Hence, an investigation was conducted to elucidate the factors that influence the removal efficacy of purified zinc ferrite on amido black 10B. Titanium dioxide prepared at different calcination temperatures was unsuccessful in removing amido black 10B, but the physical mixing of titanium dioxide prepared at suitable calcination temperatures with purified zinc ferrite had a positive effect on amido black 10B removal. Since zinc ferrite could not be used as an adsorbent to remove methyl orange and methylene blue, the photocatalytic degradation properties of zinc ferrite and its influencing factors were studied. The optimal conditions for the photocatalytic degradation of methylene blue and methyl orange by zinc ferrite are as follows: a zinc ferrite catalyst dosage of 0.15 g, an initial solution concentration of 20 mg/L, and a pH of 6.0. The dosage of the zinc ferrite/titanium dioxide composite catalyst is 0.15 g, the initial solution concentration is 20 mg/L, and the pH is 6.5. [ABSTRACT FROM AUTHOR]

The excessive use of fossil energy has caused a series of environmental problems. Hydrogen is a green energy substitute for fossil energy, and photocatalytic hydrogen production is an effective means of hydrogen production. Indium zinc sulfide catalyst has great application prospect in the field of photocatalysis due to its advantages of high stability and visible light absorption. Based on this, Cu doped indium zinc sulfide nanosheets were prepared in this paper. Compared with pure indium zinc sulfide nanosheets, copper doped indium zinc sulfide nanosheets have better photocatalytic hydrogen production performance. The design and synthesis of photocatalytic hydrogen-producing catalyst has important guiding significance. [ABSTRACT FROM AUTHOR]

Synthetic organic pigments like xanthene and azo dyes from the direct discharge of textile effluents are considered colossal global issues and attract the concern of scholars. Photocatalysis continues to be a very valuable pollution control method for industrial wastewater. Incorporations of metal oxide catalysts such as zinc oxide (ZnO) on mesoporous Santa Barbara Armophous-15 (SBA-15) support to improve catalyst thermo-mechanical stability have been comprehensively reported. However, charge separation efficiency and light absorption of ZnO/SBA-15 continue to be limiting its photocatalytic activity. Herein, we report a successful preparation of Ruthenium-induced ZnO/SBA-15 composite via conventional incipient wetness impregnation technique with the aim of boosting the photocatalytic activity of the incorporated ZnO. Physicochemical properties of the SBA-15 support, ZnO/SBA-15, and Ru-ZnO/SBA-15 composites were characterized by X-ray diffraction (XRD), N2 physisorption isotherms at 77 K, Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), and transmission electron microscopy (TEM). The characterization outcomes exhibited that ZnO and ruthenium species have been successfully embedded into SBA-15 support, andtheSBA-15 support maintains its structured hexagonal mesoscopic ordering in both ZnO/SBA-15 and Ru-ZnO/SBA-15 composites. The photocatalytic activity of the composite was assessed through photo-assisted mineralization of aqueous MB solution, and the process was optimized for initial dye concentration and catalyst dosage. 50 mg catalyst exhibited significant degradation efficiency of 97.96% after 120 min, surpassing the efficiencies of 77% and 81% displayed by 10 and 30 mg of the as-synthesized catalyst. The photodegradation rate was found to decrease with an increase in the initial dye concentration. The superior photocatalytic activity of Ru-ZnO/SBA-15 over the binary ZnO/SBA-15 may be attributed to the slower recombination rate of photogenerated charges on the ZnO surface with the addition of ruthenium. [ABSTRACT FROM AUTHOR]

In this study, novel Zn catalysts were prepared by the wet impregnation method using printing and dyeing wastewater (PDW)-modified petroleum coke (petcoke) as a carrier, and they were applied to the acetylene acetoxylation. The pretreated petroleum coke has a high specific surface area which provides sufficient space for the loading of Zn. Calcination further increases catalyst activity, but when calcination temperatures exceed 1000 °C, a significant loss of Zn occurs, resulting in a dramatic decrease in catalyst activity. This enables the conversion of acetic acid up to 85%. X-ray photoelectron spectroscopy confirmed that a large amount of N is introduced into PC from PDW, which changes the electron transfer around Zn. Temperature-programmed desorption (TPD) analysis revealed that the nitrogen-doped Zn(OAc)2 catalyst enhanced the catalytic activity by modulating the intensity of the catalyzed adsorption of acetic acid and acetylene. This study provides a new way to reuse petroleum coke and printing and dyeing wastewater to support the sustainable development of the vinyl acetate industry. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the photocatalytic performance of diverse zinc oxide catalysts containing gold nanoparticles (AuNPs), molybdenum disulfide (MoS2), and reduced graphene oxide (rGO) toward the degradation of the antibiotics levofloxacin (LFX) and ciprofloxacin (CFX) in aqueous solutions. The obtained results demonstrate that LFX is more resistant to degradation when compared with CFX and that the principal route of degradation under visible light is the formation of hydroxyl radicals. Photoluminescence (PL) measurements were employed to verify the inhibitory effect of electron–hole recombination when AuNPs, MoS2, and rGO are integrated into a semiconductor. The catalyst that achieved the highest percentage of CFX degradation was 1%Au@ZnONPs-3%MoS2-1%rGO, exhibiting a degradation efficiency of 96%, while the catalyst that exhibited the highest percentage of LFX degradation was 5%Au@ZnONPs-3%MoS2-1%rGO, displaying a degradation efficiency of 99.8%. A gas chromatography–mass spectrometry (GC-MS) analysis enabled the identification of reaction intermediates, facilitating the determination of a potential degradation pathway for both antibiotics. Additionally, recyclability assessments showed that the synthesized catalysts maintained stable photocatalytic efficiencies after 15 cycles, indicating that the heterostructures have the potential for further usage and may be tested with other organic contaminants as well. [ABSTRACT FROM AUTHOR]

Supported Cu nanoparticle catalysts are the main players in hydrogenation of CO 2 to methanol, however, the challenges in selectivity and catalyst stability have not been properly addressed due to the reverse water-gas shift reaction initiated by Cu nanoparticles and their sintering/oxidation. Here, we have developed a series of Cu,Zn-codoped ZrO 2 catalyst, in which Cu and Zn are highly dispersed into the matrix of ZrO 2. The optimal Cu,Zn-codoped ZrO 2 catalyst demonstrates outstanding performance compared with Cu-doped ZrO 2 , Zn-doped ZrO 2 and Cu-doped ZnO catalysts. Chemisorption, H 2 -D 2 exchange and in situ diffuse reflectance infrared Fourier transform spectroscopy analyses reveal that the synergy interaction between the doped Zn and Cu plays a crucial role in boosting the selective production of methanol synthesis via promoting CO 2 adsorption and H 2 dissociation. This study provides an intriguing example for the development of selective and stable Cu-catalyst for the CO 2 hydrogenation via metal-doping strategy. [Display omitted] • An efficient CO 2 -to-methanol catalyst were prepared by co-doping Cu/Zn in ZrO 2. • Co-doping Cu/Zn improved the catalytic performance of methanol formation. • Synergy interaction of Cu/Zn sites promoted CO 2 adsorption and H 2 dissociation. • Methanol formation proceeded via HCOO* -intermediated path way. • The hydrogenation of HCOO* to CH 3 O* were enhanced by co-doping Cu and Zn sites. [ABSTRACT FROM AUTHOR]

Two tetranuclear and two mononuclear Cu(II) complexes with arylhydrazones of malononitrile derived ligands (compounds 1–2 and 3–4, respectively), one trinuclear Co(II/III) complex with an arylhydrazone of acetoacetanilide (5) and one tetranuclear Zn(II) complex of 3-(2-carboxyphenyl-hydrazone)pentane-2,4-dione (6) were screened as potential catalysts in the peroxidative oxidation of cyclohexane by aqueous H2O2 in acetonitrile. The best results were attained in the presence of pyrazine-2-carboxylic acid (PCA) with 1 (26% yield, TON = 52.0) and with 2 (24%, TON = 48.0) after 4 h at 40 °C. In the presence of complexes 5 and 6, no oxygenated products were detected in the studied conditions. The employment of non-conventional conditions like supercritical carbon dioxide (scCO2) as reaction medium or microwave (MW) irradiation was assessed for complexes 1 and 2. After 6 h in acetonitrile–scCO2, at 50 °C and with HNO3 as promoter, only 17% yield was achieved using 1 as catalyst, and 21% using 2. Total yields of oxygenates up to 14 (with 1) and 13% (2) and TOFs of 56.0 and 52.0 h−1, respectively, were obtained working under MW irradiation at 70 °C and for the much shorter time of 0.5 h. [ABSTRACT FROM AUTHOR]

With the advent of biodiesel as a substitute/additive for diesel, the production of glycerol has experienced an increase, as it is an unavoidable byproduct of the biodiesel process; therefore, novel products and processes based on this triol are being very actively researched. Glycerol carbonate emerges as an advanced humectant from glycerol and a monomer for diverse polycarbonates. Its production in high yields and amounts can be achieved through the solventless transcarbonation of glycerol with other organic carbonates driven by alkaline catalysts, standing out amongst the cyclic carbonates due to its reactivity. Here, we have studied the main operational variables that affect the transcarbonation reaction of glycerol and ethylene carbonate catalyzed by zinc stearate: catalyst concentration, reagent molar ratio, and temperature. Subsequently, an appropriate kinetic model was fitted to all data obtained at 80 °C and several catalyst concentrations as well as reagent molar ratios. Finally, the selected kinetic model was extended and validated by fitting it to data obtained at several temperatures, finding that the activation energy of this reaction with this catalyst is around 69.2 kJ·mol−1. The kinetic model suggests that the reaction is bimolecular and elemental and that the process is interfacial in essence, with the catalyst dispersed in a narrow space between polar (glycerol) and nonpolar (ethylene carbonate) phases. [ABSTRACT FROM AUTHOR]

With a dinuclear zinc-ProPhenol complex as a catalyst, an efficient and novel [3 + 3] annulation of indoline-2-thiones and isatylidene malononitriles has been successfully developed via the Brønsted base and Lewis acid cooperative activation model. This practical methodology gives access to a broad range of chiral spiro[indoline-3,4′-thiopyrano[2,3-b]indole] derivatives in good yields with excellent levels of enantioselectivities (up to 88% yield and 99% ee). [ABSTRACT FROM AUTHOR]

S-doping emerged as a promising approach to further improve the catalytic performance of carbon-based materials for organic synthesis. Herein, a facile and gram-scale strategy was developed using zeolitic imidazole frameworks (ZIFs) as a precursor for the fabrication of the ZIF-derived N, S co-doped carbon-supported zinc single-atom catalyst (CNS@Zn1-AA) via the pyrolysis of S-doped ZIF-8, which was modified by aniline, ammonia and thiourea and prepared by one-pot ball milling at room temperature. This catalyst, in which Zn is dispersed as the single atom, displays superior activity in N-alkylation via the hydrogen-borrowing strategy (120 °C, turnover frequency (TOF) up to 8.4 h−1). S-doping significantly enhanced the catalytic activity of CNS@Zn1-AA, as it increased the specific surface area and defects of this material and simultaneously increased the electron density of Zn sites in this catalyst. Furthermore, this catalyst had excellent stability and recyclability, and no obvious loss in activity after eight runs. [ABSTRACT FROM AUTHOR]

Mn-doped single-atom catalysts were prepared and complexed with Au for photothermal and enzymatic therapy. PSMCA can catalyze the decomposition of glucose to H 2 O 2 , and further catalyze the generation of ROS. In addition, PSMCA can produce photothermal conversion under the irradiation of 808 nm laser. [Display omitted] As an emerging technology, nanocatalytic medicine attracts much attention, especially the ones according to the enzymatic reaction by using excess H 2 O 2 in the tumor. Among various candidates, single-atom catalyst (SAC) revealed unique and outstanding redox reaction performance, since the active sites consisting of single metal atoms may achieve the maximum utilization of metal atoms and emerge obviously amplified reaction rate. Here we developed an M−N x (M = Mn, Zn) center-based SAC with a hollow structure by calcination of Mn2+-doped zeolitic imidazolate frameworks (ZIF-8), and PEGylation was applied to improve the hydrophilicity. According to the enzymatic reaction, the M−N x (M = Mn, Zn) centers have an inherent peroxidase-like activity to catalyze over-expressed H 2 O 2 in the weak acidic tumor microenvironment and generate a large amount of toxic reactive oxygen species (ROS) like hydroxyl radicals for therapy. To keep efficient therapeutic output, we integrated the hollow SAC with Au which could expend the glucose in tumor and supply H 2 O 2 as the substrate of peroxidase-like activity. Better yet, Au may boost the photothermal effect of SAC and offer another non-invasive photothermal therapy (PTT) to promote the effect of tumor removal. This platform provided a new idea for the construction of more efficient peroxidase-like activity in tumor therapy. [ABSTRACT FROM AUTHOR]

In this study, flake Zn 2 Ti 3 O 8 , TiO 2 and rod ZnO catalysts were successfully synthesized by hydrothermal and calcination methods, and the catalytic performance of the three catalysts for MgH 2 was compared. Notably, Zn 2 Ti 3 O 8 had a significant synergistic enhancement effect on the dehydrogenation temperature and desorption kinetics of MgH 2. The experimental results showed that the dehydrogenation of MgH 2 + 12 wt% Zn 2 Ti 3 O 8 composite started at about 195 °C, which was about 150 °C lower than that of pure MgH 2. Moreover, at 325 °C, MgH 2 released only 3.06 wt% H 2 in 20 min, whereas the MgH 2 + 12 wt% Zn 2 Ti 3 O 8 composite released the same amount of hydrogen at 250 °C in 3 min. After complete dehydrogenation, the MgH 2 + 12 wt% Zn 2 Ti 3 O 8 composite initiated hydrogen uptake at 40 °C and absorbed about 6.05 wt% of H 2 in 60 min at 200 °C. The hydrogen uptake activation energy and dehydrogenation activation energy of the composites were reduced by 24.56 kJ/mol and 44.67 kJ/mol, respectively, when compared to the pure MgH 2. Cycling experiments showed that after 20 cycles, the MgH 2 + 12 wt% Zn 2 Ti 3 O 8 composite maintained good cycling stability and the hydrogen storage capacity was still more than 96 %. Therefore, the composite exhibits excellent catalytic and hydrogen storage properties, and has potential applications in improving the hydrogen release rate and reducing the activation energy. • In this study, a new material, Zn 2 Ti 3 O 8 , was designed and prepared as a catalyst. • MgH 2 +12 wt% Zn 2 Ti 3 O 8 exhibits lower hydrogen absorption/desorption temperatures and faster rates. • The composite material MgH 2 +12 wt% Zn 2 Ti 3 O 8 has excellent cycling stability. [ABSTRACT FROM AUTHOR]

In this study, we have synthesized β-Zn(OH) 2 /ZnO heterostructures via a simple one-pot hydrothermal method followed by calcination at different temperatures under air for electrochemical dopamine (DA) detection. We found that the synergetic effect between optimized β-Zn(OH) 2 and ZnO phases in β-Zn(OH) 2 /ZnO heterostructures boosts electrocatalytic activity. Moreover, β-Zn(OH) 2 /ZnO heterostructures calcined at 300 °C (i.e.,β-Zn(OH) 2 /ZnO 300) showed enhanced electrochemical activity towards DA oxidation due to its larger electrochemical active surface area and higher adsorption capacity compared to other β-Zn(OH) 2 /ZnO heterostructures and ZnO. Additionally, β-Zn(OH) 2 /ZnO 300 heterostructures demonstrated remarkable DA selectivity in the presence of over eight biomolecules, achieving rapid detection response in less than 10 seconds with a low detection limit of 0.17 nM and 1.0 nM within a linear range of (1.75–263 nM) and (263–1300 nM), respectively. Moreover, β-Zn(OH) 2 /ZnO 300 heterostructures showed remarkable reproducibility (98.8 %), high stability (98.1 %), and real-time DA detection in human urine samples with a recovery rate ranging from 95.9 % to 103.2 %. Therefore, β-Zn(OH) 2 /ZnO heterostructures, especially those optimized under 300 °C, possess great potential for electrochemical applications, particularly in DA detection. [Display omitted] • β-Zn(OH) 2 /ZnO heterostructures fabricated via facile hydrothermal method followed by calcination. • β-Zn(OH) 2 /ZnO 300 possess superior electrocatalytic activity toward DA detection. • ZnO in β-Zn(OH) 2 /ZnO heterostructure facilitate fast electron transfer. • β-Zn(OH) 2 /ZnO 300 demonstrates low LOD, excellent selectivity and good stability. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET), also known as polyester, is extensively utilized in the textile industry. The most commonly used chemical degradation method of PET is ethylene glycol (EG) glycolysis, which enables a closed-loop recovery process suitable for large-scale production. In this study, a new type of heterogeneous catalyst (Zn-MCM-41) was proposed for glycolysis of waste PET textiles, and their catalytic performance is much higher than other mesoporous zeolites. Under optimal reaction conditions, over Zn-MCM-41–25 (Si/Al molar ratio of 25) catalyst PET achieved a conversion ratio of 100 %, with bis-hydroxyethyl terephthalate (BHET) yield reaching 81.4 %. XPS results show that zinc is mainly presented as the state of Zn2+, resulting in excellent stability of the catalyst. HPLC and LCMS analyses were conducted on the products obtained from PET glycolysis, revealing that only a small amount of oligomers were generated during the process. These oligomers primarily consisted of dimer [BHET] 2 and trimer [BHET] 3. The Zn-MCM-41–25 catalyst also demonstrates exceptional performance in colored waste PET textiles glycolysis. Furthermore, we investigated the kinetics of PET glycolysis and determined it to follow first-order kinetics with an activation energy value of 210.03 kJ mol−1. Additionally, HPLC methods was established for analyzing glycolysis products and recovering catalysts using a simple filtration technique. The results demonstrate that even after five cycles, the catalyst maintains its high catalytic activity. [Display omitted] • Heterogeneous glycolysis catalyst with high efficiency and stability for waste PET textiles. • The proposed catalyst can be applied for both colorless and colored textiles. • BHET yield for colorless and colored PET glycolysis can achieve above 94 % and 91 %, respectively. • The potential mechanism of ester chain breaking over Zn2+ active center was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • • Effects of halogen and imidazolium on the decomposition of EC were explored. • • The catalytic effects of halogen on polymerization side reactions were revealed. • • The essential active site of the composite catalyst was identified. • • Mechanism was proposed by using combined molecular dynamics and DFT calculation. Coupling of carbon dioxide (CO 2) to cyclic carbonates with an epoxide and further into linear carbonates as the indispensable solvents for the lithium-ion batteries has been being one of the hottest topics in transforming CO 2 into high value-added chemicals. Nevertheless, the extremely ultrahigh purity requirement for them causes a low efficiency and a modest yield due to the undesired reactions and byproducts occurring in the separation and purification sections. In this work, a novel imidazolium based ionic liquid catalyst system with different anions and cations was studied by a thorough insight into the decomposition reaction of ethylene carbonate (EC), which reveals the synergistic mechanism of the composite catalysts both in section of cyclic carbonate separation from the catalyst for recirculated utilization and purification from the byproducts, and in section of synthesis with high efficiency. Effects of imidazolium cations and halogen anions in the ionic liquid molecule on EC decomposition were investigated by the elaborately designed experiments, thermodynamic estimations, molecular dynamics simulation and DFT assessment. It was found that combining imidazole salts and zinc halides can greatly boost the activity of EC synthesis and decomposition with the effective structure of catalytic center being [EMIm]ZnX 4. Furthermore, it was indicated that Br- has a higher activity for EC synthesis and its reversed pyrolysis, while Cl- will promote a side reaction of ring-opening polymerization of EC. Finally, a most favorable catalyst composition with ZnBr 2 and [EMIm]Br for EC synthesis was achieved with a high efficiency in synthesis and a low tendency to initiate the side reactions in separation section. [ABSTRACT FROM AUTHOR]

In this work, a novel acidic catalyst based on protic ionic liquid (1-metylimidazoluim triflate, [Hmim][OTf]) and ZnO was developed. First, analysis of the structure was developed by HRMS, FT-IR and Raman spectroscopy, NMR, and X-ray absorption spectroscopy. The obtained results revealed an alternative structure and mechanism of the formation of the ionic liquid/ZnO adduct ([Hmim][OTf]) 3 Zn. The developed liquid system was created based on the molar ratio of ([Hmim][OTf]) 3 Zn and was shown as an effective acidic catalyst and solvent in the alternative synthesis of plasticizers. In particular, ([Hmim][OTf]) 3 Zn (10 mol%) displayed catalytic efficiency for the esterification of succinic acid, adipic acid, and lactic acid with two alcohols 1-butanol and 2-etylhexanol. For 2-ethyl-1-hexanol, full conversion of succinic acid was achieved after 1 h at 130 °C. The synergistic effect of the ionic liquid and ZnO was demonstrated by comparing the catalytic efficiency of the individual components. ([Hmim][OTf]) 3 Zn was used in six consecutive reaction cycles without a significant decrease in catalytic efficiency. Additionally, structural studies provided the foundation for the rational design and development of an acidic catalyst, consequently leading to a more environmentally friendly and economically feasible process. [Display omitted] • Complex salt based on ZnO and protic ionic liquid revealed liquid nature. • Alternative plasticizers were obtained via esterification with acidic catalyst. • Synergistic effects of protic ionic liquid and ZnO enhance efficiency in catalysis. • The emergence of a biphasic system led to an shift in reaction equilibrium. • Simplicity of product isolation via phase separation with lack of Zn leaching. [ABSTRACT FROM AUTHOR]

Transition-metal catalyzed carbosilylation of alkenes using carbon electrophiles and silylmetal (-B, -Zn) reagents as the nucleophiles offers a powerful strategy for synthesizing organosilicones, by incorporating carbon and silyl groups across on C-C double bonds in one step. However, to the best of our knowledge, the study of silylative alkenes difunctionalization based on carbon and silyl electrophiles remains underdeveloped. Herein, we present an example of silylative alkylation of activated olefins with unactivated alkyl bromides and chlorosilanes as electrophiles under nickel catalysis. The main feature of this protocol is employing more easily accessible substrates including primary, secondary and tertiary alkyl bromides, as well as various chlorosilanes without using pre-generated organometallics. A wide range of alkylsilanes with diverse structures can be efficiently assembled in a single step, highlighting the good functionality tolerance of this approach. Furthermore, successful functionalization of bioactive molecules and synthetic applications using this method demonstrate its practicability. Synthetic methodologies that enable the formation of C‒Si bonds in organic molecules are desirable. Here, the authors report the nickel-catalyzed reductive alkylsilylation of acrylonitrile with unactivated alkyl bromides and chlorosilanes. [ABSTRACT FROM AUTHOR]

Dehydration of glucose for the production and separation of 5-hydroxymethylfurfural (5-HMF) with high purity has been performed. For selective production of 5-HMF from glucose, a new sulfated-ZnO catalyst with a combined hexagonal-monoclinic phase was developed and characterized by several techniques. The catalyst characterization results demonstrated a significant variation of physicochemical properties of hexagonal ZnO after sulfate impregnation. The glucose dehydration was performed in a glass reactor in a dimethyl sulfoxide (DMSO) medium. The effect of several important reaction parameters including temperature (120–160 °C), time (1–8 h), catalyst loading (25–100 wt%), and sulfate loading on ZnO with respect to glucose (1.5–4.5M) was evaluated. Results demonstrated that the sulfated-ZnO catalyst containing both the Brønsted (B) and Lewis (L) acid sites was very active and selective to 5-HMF compared to pure hexagonal ZnO containing only Lewis acidic sites (LAS). It was also observed that the higher (B + L) acidity of catalysts propagated the rehydration process, which led to the formation of various unwanted side products. The maximum glucose conversion of 96.2% with ~35% yield of 5-HMF was obtained at 160 °C after 6 h of reaction, with 2.5M-SO 4 2−/ZnO catalyst. Among all others, the 2.5M-SO 4 2−/ZnO catalyst was the best due to the presence of an optimum acidity with an appropriate B/L ratio. Further, the catalyst separation and recycling studies were performed. The results revealed that the 2.5M-SO 4 2−/ZnO catalyst could be recycled multiple times without substantial loss of catalytic activity and 5-HMF yield. Furthermore, a liquid-liquid extraction process was developed, demonstrating that almost 100% of 5-HMF could be extracted from the product solution with ~97% purity. [Display omitted] • The SO 4 2− impregnated on ZnO generated additional Lewis and Brønsted acid sites. • 2.5M-SO 4 2−/ZnO demonstrated ~35% 5-HMF yield with ~96.2% conversion at 160 °C. • Catalyst developed can be recycled with constant activity and 5-HMF yield. • 5-HMF was separated from the product mixture with very high purity. [ABSTRACT FROM AUTHOR]

Hybrid Cu-SSZ-13 zeolite catalyst are prepared and analyzed for NH3-SCR activity with different topologies in the present investigation. Cu-SSZ-13 was synthesized by ionexchange method, and hybrid Cu-SSZ-13 was synthesized by wet-impregnation method with three different molar ratios between Znx-CNTy as 1:5, 1:10, & 1:15 and maintained as 1:5 mass ratio between Znx-CNTy/Cu-SSZ-13 hybrid zeolite catalysts. The catalytic activity measured at a temperature window of 100ËšC to 550ËšC concludes hybrid Zn1-CNT10/Cu-SSZ-13 catalyst exhibits high NH3-SCR performance (100%) at a temperature of 180ËšC to 475ËšC and by anti-sulfur activity, it exhibits 80% NOx at 300ËšC for 8hrs in the presence of SO2 gas in feed aid that addition of Zn species and CNTs influence Cu-SSZ-13 in NH3-SCR activity finding them to be a better catalyst for NOx reduction. [ABSTRACT FROM AUTHOR]