Metal Doping Effect of the M–Co₂P/Nitrogen-Doped Carbon Nanotubes (M = Fe, Ni, Cu) Hydrogen Evolution Hybrid Catalysts

The enhancement of catalytic performance of cobalt phosphide-based catalysts for the hydrogen evolution reaction (HER) is still challenging. In this work, the doping effect of some transition metal (M = Fe, Ni, Cu) on the electrocatalytic performance of the M–Co₂P/NCNTs (NCNTs, nitrogen-doped carbon nanotubes) hybrid catalysts for the HER was studied systematically. The M–Co₂P/NCNTs hybrid catalysts were synthesized via a simple in situ thermal decomposition process. A series of techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, transmission electron microscopy, and N₂ sorption were used to characterize the as-synthesized M–Co₂P/NCNTs hybrid catalysts. Electrochemical measurements showed the catalytic performance according to the following order of Fe–Co₂P/NCNTs > Ni–Co₂P/NCNTs > Cu–Co₂P/NCNTs, which can be ascribed to the difference of structure, morphology, and electronic property after doping. The doping of Fe atoms promote the growth of the [111] crystal plane, resulting in a large specific area and exposing more catalytic active sites. Meanwhile, the Fe^δ+ has the highest positive charge among all the M–Co₂P/NCNTs hybrid catalysts after doping. All these changes can be used to contribute the highest electrocatalytic activity of the Fe–Co₂P/NCNTs hybrid catalyst for HER. Furthermore, an optimal HER electrocatalytic activity was obtained by adjusting the doping ratio of Fe atoms. Our current research indicates that the doping of metal is also an important strategy to improve the electrocatalytic activity for the HER

Reactive Adsorption Desulfurization on Cu/ZnO Adsorbent: Effect of ZnO Polarity Ratio on Selective Hydrogenation

The desulfurization activity and selective hydrogenation of Cu/ZnO adsorbents on the different polarity ratios of ZnO as supports was investigated in reactive adsorption desulfurization. The ZnO particles were synthesized by the hydrothermal process, and CuO/ZnO adsorbents were synthesized by incipient impregnation method. The structure and morphology of the ZnO and CuO/ZnO were characterized by X-ray diffraction (XRD), N₂ adsorption–desorption, X-ray photoelectron spectra (XPS), scanning electron microscope/selected area electron diffraction (SEM/SAED), transmission electron microscopy (TEM), and temperature-programmed reduction (TPR). The surface area and polarity ratio of ZnO supports were controlled by the calcination temperature and concentration of P₁₂₃, respectively. More reactive activity sites were provided by the high surface area of ZnO supports, thus improving the desulfurization activity. The polarity ratio of ZnO may strongly influence the hydrogenation reactions of olefins. The selective hydrogenation increased with the value of polarity ratios

Amorphous CuPt Alloy Nanotubes Induced by Na₂S₂O₃ as Efficient Catalysts for the Methanol Oxidation Reaction

Here we propose amorphous CuPt alloy hollow nanotubes as efficient catalysts for the methanol oxidation reaction (MOR) prepared by Na₂S₂O₃-assisted galvanic replacement reaction. The formation mechanism can be explained by the nanoscale Kirkendall-effect-induced hollowing process of the galvanic replacement reaction. The electrochemical tests suggest that the amorphous CuPt alloy exhibits better MOR activity and stability than the crystalline CuPt and commercial Pt/C catalysts, which can be ascribed to the enhanced CO tolerance ability of amorphous alloy. XPS measurements demonstrate that the enhanced anti-CO poison characteristic of amorphous CuPt alloy originates from the strong interaction between Pt and Cu atoms as a result of a unique crystallization state. This research not only provides a facile approach to synthesize amorphous alloy but also opens up an interesting way for amorphous Pt-based alloy to apply to the MOR

Highly Active CoMoS/Al₂O₃ Catalysts ex Situ Presulfided with Ammonium Sulfide for Selective Hydrodesulfurization of Fluid Catalytic Cracking Gasoline

An improved ex situ presulfidation method for the preparation of the CoMoS/γ-Al₂O₃ catalyst was developed with ammonium sulfide as the sulfiding agent, and the prepared catalysts were evaluated in selective hydrodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline. The selectivity of the ex situ presulfided catalysts was more than 4 times of that of the in situ presulfided catalysts. The characterization by XRD, HRTEM, XPS, TPR, and FT-IR indicated that ammonium sulfide effectively reacted with the supported Mo oxide to form ammonium tetrathiomolybdate as intermediate, thus realizing the more complete sulfidation of Mo oxide. However, the supported Co oxide could not be sulfided by ammonium sulfide, and the delayed sulfidation would not hinder the easy growth of MoS₂ particles, subsequently lead to the significantly longer slab lengths of MoS₂ particles than that of the in situ presulfided catalyst, which effectively decreased the number of active sites for olefins, thus inducing much higher HDS selectivity

Hydrodesulfurization of 4,6-Dimethyldibenzothiophene over CoMo Catalysts Supported on γ‑Alumina with Different Morphology

Nanostructured γ-alumina with two different morphologies (rod-like and cube-like) was used as support for CoMo hydrodesulfurization catalyst. Both γ-aluminas were prepared by thermal decomposition of ammonium aluminum carbonate hydroxide precursor, which was synthesized by a convenient hydrothermal method at two pH values. Fourier transform infrared spectroscopy of prydine adsorption, thermogravimetric analysis, and ²⁷Al magic angle spinning (MAS) NMR showed that the rod-like γ-alumina exhibited a lower acidity than the cube-like γ-alumina. The result of X-ray diffraction and temperature-programmed reduction indicated that CoMo oxidic catalysts supported on the rod-like γ-alumina presented higher reducibility compared to those of cube-like γ-alumina, because more β-CoMoO₄ was formed on the surface of the rod-like γ-alumina than that of the cube-like γ-alumina. After sulfidation, a large stack with slightly longer MoS₂ slabs was formed on the rod-like γ-alumina supports, thereby creating a catalyst with higher hydrodesulfurization activity and hydrogenation selectivity. The morphology of γ-alumina has an influence on the activity and selectivity of the as-synthesized CoMo catalyst

SDS polyacrylamide gel electrophoresis pattern of collagens from jellyfish mesoglea.

<p>STD: molecular weight marker; RTC: rat tail type I collagen; PSC: pepsin soluble collagen; ASC: acid soluble collagen.</p

Viability of cells cultured in direct contact with various biomaterials at 1, 3 and 7 days, as determined by MTT assay.

<p>Viability is expressed as a percentage of live cells compared to positive control cells: (1) uncross-linked 2.5 mg/ml collagen sponges; (2) 2.5 mg/ml collagen sponges cross-linked with 100 mM EDC for 24h; (3) uncross-linked 3.3 mg/ml collagen sponges; (4) 3.3 mg/ml collagen sponges cross-linked with 100 mM EDC for 24h.</p

Total Synthesis of (+)-Fusarisetin A Driven by a One-Pot Four-Reaction Process

A concise, asymmetric total synthesis of (+)-fusarisetin A, a hybrid natural product, has been achieved. A one-pot four-reaction process efficiently delivered the tetracycle <b>2</b> which served as a key intermediate for the synthesis of the title natural product and its analogues through amino acid incorporation

Amino acid composition of the collagen from jellyfish (PSC) and calf-skin collagen (results are expressed as residues/1000 residues).

<p>Amino acid composition of the collagen from jellyfish (PSC) and calf-skin collagen (results are expressed as residues/1000 residues).</p

Fourier transform infrared spectrum of different collagen sponges.

<p>A, uncross-linked collagen sponge; B, collagen sponge cross-linked with 50mM EDC for 12h; C, collagen sponge cross-linked with 100mM EDC for 24h (The unit of the numbers in figure is cm^-1).</p