Search

Herein, a new template carbonization method is used to prepare calcite‐type nano‐calcium carbonate (CaCO3) with a core–shell structure using calcium hydroxide as a solute and Pluronic F‐127 as a templating and pore‐forming agent. Dopamine hydrochloride is added to control the size of calcium hydroxide particles. The morphology, particle size, and crystal type of CaCO3 are characterized via transmission electron microscopy, X‐ray diffraction, nanoparticle size, and zeta potentiometer. The creation of core–shell calcium carbonate nanoparticles is examined in relation to reaction circumstances (i.e., additive sequence, additive amount, and additive mixing time), carbonization temperature, liquid flow rate, and templates with varying chain lengths. Furthermore, a discussion is held regarding the formation mechanism of spherical core–shell calcium carbonate that is created using the innovative template carbonization method. The results show that the order, amount, liquid flow rate, and template type of additives have a significant effect on the crystal shape of calcium carbonate nanoparticles. The mixing time of additives has a significant effect on the particle size of calcium carbonate nanoparticles. Interestingly, the thickness of the shell depends on the carbonization temperature, and too slow or too fast flow rate will lead to the formation of cyclic calcium carbonate nanoparticles. [ABSTRACT FROM AUTHOR]

Herein, a novel bimetallic nickel molybdenum nitride (Ni3Mo3N) catalyst is reported for the first time for the hydrogenation of dimethyl oxalate (DMO) to ethanol (EtOH). Remarkably, the Ni3Mo3N-600 catalyst realizes a remarkable 97.5% EtOH yield at a low pressure of 0.5 MPa and a low H2/DMO molar ratio of 10. Moreover, it exhibits exceptional catalytic stability for at least 300 h, marking the first instance of achieving such high EtOH yield under mild reaction conditions. The present study investigates the impact of different reduction temperatures on the catalyst, and various characterization analyses reveal the formation of Ni3Mo3N. The electron-rich structure of the Ni3Mo3N-600 catalyst facilitates the activation of C＝O and enhances the adsorption and dissociation of H2. Specifically, the low-valence Mo promotes the activation of carbonyl oxygen, while Ni0 facilitates the adsorption and dissociation of H2, considerably enhancing the deep hydrogenation ability of the Ni3Mo3N-600 catalyst. Furthermore, the well-defined crystallinity of the Ni3Mo3N-600 catalyst coupled with Lewis acid sites that promote C＝O adsorption and activation, Brønsted acid sites that facilitate C–O adsorption and activation, and hydrogenation sites collectively contribute to the efficient conversion of DMO to EtOH. This study presents new insights into designing high-performance catalysts for the hydrogenation of DMO toward EtOH. [ABSTRACT FROM AUTHOR]

• The Ni-In/C catalyst is prepared by a simple one-pot method, that is, the catalyst preparation is simple and the cost is low. • The influence of the molar ratio of Ni/In on the catalytic performance and the reasons were described. When the molar ratio of Ni/In is 3, InNi 3 C 0.5 is formed, and the doping of In increases the content of defect sites and hydroxyl group. • The influence of carbonization temperature on catalytic performance and the reasons are expounded. Carbonization temperature affected the defect sites and hydroxyl content of catalyst. • The selectivity of 90.5 % ethanol can be achieved under the premise of full conversion of dimethyl oxalate, which has excellent industrial potential. The Ni-In/C catalyst, prepared using a one-pot method, demonstrates superior catalytic performance compared to the Ni/C catalyst in the hydrogenation of dimethyl oxalate (DMO) to ethanol (EtOH). The introduction of doping results in the formation of defect sites and InNi 3 alloy, enhancing both the adsorption of DMO and the activation of H 2. Additionally, the presence of -OH groups (acting as Bronsted acid sites) on the carbon surface activates C-O, thereby effectively promoting the deep hydrogenation of intermediate products to produce EtOH. The catalyst exhibits remarkable industrial potential by achieving high ethanol yield through a straightforward preparation method, while maintaining low Ni content. [Display omitted] [ABSTRACT FROM AUTHOR]

MG has a special molecular structure, and MG is an important chemical intermediate with promising applications. Ag−Ce/ZrO2 catalysts with different contents were prepared for hydrogenation of DMO to MG by equal volume impregnation. The content of Ag and the type of additives were screened. According to the effects of different additives on the conversion rate of DMO and the selectivity of MG, Ce was finally selected as the optimal additive metal. These were characterized by XRD, XPS, BET, H2‐TPR. The addition of Ce helps the catalyst to form more oxygen vacancies and Ag2O is more easily reduced to Ag monomers. The performance test results of the catalyst showed that the addition of appropriate amount of Ce has a certain promotion effect on the hydrogenation performance of the catalyst, The yield of MG using the 8Ag−Ce1/ZrO2 catalyst was significantly better than that of the Ag/ZrO2 catalyst. [ABSTRACT FROM AUTHOR]

• The Fe(OH) 3 /Ni-NiO heterojunction was successfully prepared. • The Fe(OH) 3 /Ni-NiO as bifunctional catalysts showed high HER and OER activities. • The heterogeneous interface between Ni, NiO and Fe(OH) 3 promoted the HER process. Exploring economic-efficient bifunctional catalysts is critical for the production of green hydrogen through water splitting. Herein, we fabricate a novel hybrid catalyst with three-phase heterojunction (Fe(OH) 3 /Ni-NiO) via a simple electrodeposition and chemical precipitation method. Benefiting from the desirable amorphous-crystal interfaces, the electronic structure of Ni, NiO and Fe(OH) 3 is regulated, which will optimize the adsorption of H intermediates (H*) and also reduce the kinetic barrier for the hydrogen evolution reaction (HER). The optimal Fe(OH) 3 –3/Ni-NiO/CC shows superior bifunctional activity with low overpotentials of 66 mV for HER and 220 mV for OER at 10 mA cm−2 in alkaline solution, respectively, as well as remarkable durability over a period of 40 h. Besides, Fe(OH) 3 –3/Ni-NiO/CC requires 1.52 and 1.72 V to deliver 10 and 100 mA cm−2 and shows no obvious increase in current within 40 h toward overall water splitting. Experimental and theoretical results show that the HER process is promoted by the synergistic effect of electronic redistribution between Ni, NiO and Fe(OH) 3 due to the construction of three phase crystalline-amorphous heterogeneous interface. Meanwhile, Fe(OH) 3 and NiO appeared reconstruction, transforming into FeOOH and NiOOH during OER process, respectively. This work offers a simple synthesis method for designing bifunctional catalysts for water splitting. We fabricate a novel hybrid catalyst with three-phase heterojunction (Fe(OH) 3 /Ni-NiO) via a simple electrodeposition and chemical precipitation method. The optimal Fe(OH) 3 -3/Ni-NiO/CC shows superior bifunctional activity at 10 and 100 mA cm−2 with voltages of 1.52 and 1.88 V for overall water splitting and no obvious increase in current within 40 h. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-Ag x /TiO 2 catalyst with low metal content were synthesized. • Co-Ag 0.7 /TiO 2 catalyst exhibits exceptional hydrogenation performance of dimethyl oxalate. • The catalyst achieves excellent catalytic performance at lower hydrogen consumption. • The synergistic interaction between Co and Ag is conducive to the adsorption and activation of DMO and H 2. • Providing a potential new avenue for designing low loading catalysts for dimethyl oxalate hydrogenation. The Co-Ag x /TiO 2 catalysts with low mass content of Co and Ag were synthesized through the impregnation method and investigated for dimethyl oxalate (DMO) hydrogenation to methyl glycolate (MG). Remarkably, the Co-Ag 0.7 /TiO 2 catalyst with an Ag concentration of 0.7 wt%, exhibited an impressive yield of MG of ∼94.4 %, surpassing the yields of MG obtained with Co/TiO 2 (∼54 %) and Ag 0.7 /TiO 2 (∼69 %) catalysts. Various characterizations elucidated that the exceptional catalytic performance of Co-Ag 0.7 /TiO 2 can be ascribed to the synergy between Co and Ag, resulting in the formation of AgCoO 2 as high active site can improve the adsorption and activation of DMO and H 2 on catalyst surface. Additionally, the doping of a small amount of Ag regulated the contents of Lewis acidic and Brønsted acidic sites, leading to a high conversion of DMO and selectivity of MG. Furthermore, the excellent MG yield and long-term stability (at least 200 h) facilely obtained over our catalyst under mild reaction conditions guarantee a feasible prospect in the industrial application. This study not only unraveled the superior performance of the Co-Ag synergistic catalyst, but also carried significant implications for developing catalysts with low-content in DMO hydrogenation to MG. [ABSTRACT FROM AUTHOR]

In recent years, central precocious puberty (CPP) in children is becoming more common, which seriously affects their physical and psychological health and requires finding a safe and effective treatment method. The aim of this study was to investigate the therapeutic effect of melatonin on CPP. A CPP model was established by subcutaneous injection of 300 micrograms of danazol into 5-day-old female mice, followed by treatment with melatonin and leuprolide. The vaginal opening was checked daily. Mice were weighed, gonads were weighed, gonadal index was calculated, and gonadal development was observed by hematoxylin and eosin (HE) staining. Serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E 2) levels were measured by ELISA. By using RT-PCR and Western blotting, the mRNA and protein expression of the hypothalamus Kiss-1, Kiss-1 receptor (Kiss1R), gonadotropin-releasing hormone (GnRH), and pituitary GnRH receptor (GnRHR) were identified. The results showed that melatonin delayed vaginal opening time and reduced body weight, gonadal weight and indices in female CPP mice. Melatonin treatment prevents uterine wall thickening and ovarian luteinization in female CPP mice. Melatonin treatment reduces serum concentrations of FSH, LH, and E 2 in female CPP mice. Melatonin suppressed the expressions of Kiss-1, Kiss1R and GnRH in the hypothalamus, and the expression of GnRHR in the pituitary of the female CPP mice. Our results suggest that melatonin can inhibit the hypothalamic-pituitary-gonadal (HPG) axis by down-regulating the Kiss-1/Kiss1R system, thereby treating CPP in female mice. [ABSTRACT FROM AUTHOR]