Effect of high-pressure homogenization on maize starch-stearic acid and maize starch-stearic acid-whey protein complexes

The maize starch (MS)-stearic acid (SA) and MS-SA-whey protein (WP) complexes were prepared using the high-pressure homogenization (HPH). Results from X-ray diffraction (XRD) showed that MS-SA complexes presented an increase in the long-range molecular order with increasing the homogenization pressure, and MS-SA-WP complexes showed only an increase with increasing the homogenization pressure from 10 to 50 MPa. Results from differential scanning calorimetry (DSC) and Raman spectroscopy showed that the amount of complexes and the short-range order of both MS-SA and MS-SA-WP complexes increased with increasing the homogenization pressure. The addition of WP to MS-SA altered significantly the structure and digestion of complexes. Results revealed that MS-SA-WP complexes have more ordered structure and lower digestion than the corresponding MS-SA complexes. The digestibility of all complexes decreased with increasing the homogenization pressure. There was a significant correlation between the digestibility and structural characteristics of complexes. Complexes with better structural stability have better anti-digestion properties. The obtained results are helpful in understanding the structure and digestibility of complexes prepared by HPH, which is valuable for controlling the quality and nutrition of starchy food

The influence of poly (2-methoxyaniline-5-sulfonic acid) on the electrochemical and photochemical properties of a highly luminescent ruthenium complex

Immobilisation of a luminescent material on an electrode surface is well known to substantially modulate its photophysical and electrochemical properties. Here a positively charged ruthenium metal complex ([Ru(bpy)(3)](2+)) is immobilised on all electrode surface by ion paring with a sulfonated conducting polymer poly(2-methoxyaniline-5-sulfonic acid), (PMAS). Significantly, our study reveals that the electron transport between the ruthenium metal centres can be greatly enhanced due to the interaction with the conducting polymer when both are surface confined. Charge transfer diffusion rates in the present system are an order of magnitude faster than those found where the metal centre is immobilised within a non-conducting polymeric matrix. Electron transport appears to be mediated through the PMAS conjugated structure, contrasting with the electron hopping process typically observed in non-conducting metallopolymers. This increased regeneration rate causes the ruthenium-based electrochemiluminescence (ECL) efficiency to be increased. The impact of these observations on the ECL detection of low concentrations of disease biomarkers is discussed. (c) 2007 Published by Elsevier Ltd

Recent Advances of Modified Ni (Co, Fe)-Based LDH 2D Materials for Water Splitting

Water splitting technology is an efficient approach to produce hydrogen (H2) as an energy carrier, which can address the problems of environmental deterioration and energy shortage well, as well as establishment of a clean and sustainable hydrogen economy powered by renewable energy sources due to the green reaction of H2 with O2. The efficiency of H2 production by water splitting technology is intimately related with the reactions on the electrode. Nowadays, the efficient electrocatalysts in water splitting reactions are the precious metal-based materials, i.e., Pt/C, RuO2, and IrO2. Ni (Co, Fe)-based layered double hydroxides (LDH) two-dimensional (2D) materials are the typical non-precious metal-based materials in water splitting with their advantages including low cost, excellent electrocatalytic performance, and simple preparation methods. They exhibit great potential for the substitution of precious metal-based materials. This review summarizes the recent progress of Ni (Co, Fe)-based LDH 2D materials for water splitting, and mainly focuses on discussing and analyzing the different strategies for modifying LDH materials towards high electrocatalytic performance. We also discuss recent achievements, including their electronic structure, electrocatalytic performance, catalytic center, preparation process, and catalytic mechanism. Furthermore, the characterization progress in revealing the electronic structure and catalytic mechanism of LDH is highlighted in this review. Finally, we put forward some future perspectives relating to design and explore advanced LDH catalysts in water splitting

In-situ synthesis of N, S co-doped hollow carbon microspheres for efficient catalytic oxidation of organic contaminants

Metal-free heteroatom doped nanocarbons are promising alternatives to the metal-based materials in catalytic ozonation for destruction of aqueous organic contaminants. In this study, N, S co-doped hollow carbon microspheres (NSCs) were synthesized from the polymerization products during persulfate wet air oxidation of benzothiazole. The contents of doped N and S as well as the structural stability were maneuvered by adjusting the subsequent N-2-annealing temperature. Compared with the prevailing single-walled carbon nanotubes, the N-2-annealed NSCs demonstrated a higher catalytic ozonation activity for benzimidazole degradation. According to the quantitative structure-activity relationship (QSAR) analysis, the synergistic effect between the graphitic N and the thiophene-S which redistributed the charge distribution of the carbon basal plane contributed to the activity enhancement of the N-2-annealed NSCs. Additionally, the hollow structure within the microspheres served as the microreactor to boost the mass transfer and reaction kinetics via the nanoconfinement effects. Quenching and electron paramagnetic resonance (EPR) tests revealed that benzimidazole degradation was dominated by the produced singlet oxygen (O-1(2)) species, while hydroxyl radicals ((OH)-O-center dot) were also generated and participated. This study puts forward a novel strategy for synthesis of heteroatom-doped nanocarbons and sheds a light on the relationship between the active sites on the doped nanocarbons and the catalytic performance. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences

Effect of Catalyst Structure on Growth and Reactivity of Carbon Nanofibers over Ni/MgAl₂O₄

The structure of Ni catalyst has a significant effect on the growth and reactivity of carbon nanofibers (CNFs) formed from methane decomposition. We present here a detailed study on this structure effect with Ni/MgAl₂O₄ as model catalyst. Different catalyst structures were obtained via dielectric barrier discharge (DBD) plasma and thermal decomposition. For the thermal decomposed catalyst, a complex combination of microfacets presents with a higher content of defects. A diffusion interfacial region is formed due to the migration of Ni atoms into the support. However, a higher concentration of close-packed plane is observed for the DBD decomposed catalyst with less defects and a clean interface between Ni particle and support. The CNFs over the DBD decomposed sample show smaller diameter and narrower distribution with a smaller slope of graphene layers but enhanced activity toward O₂ and CO₂, indicating better coke resistance for methane conversion

On the origin of the giant Hall effect in magnetic granular metals

A large, by a factor of similar to 10(3)-10(4), enhancement of Hall effect in cosputtered magnetic granular metals such as (NiFe)(x)-(SiO2)(1-x) near the metal-insulator transition has been termed giant Hall effect (GHE). It is associated with a high resistivity which increases slowly with decreasing temperature. We suggest that particle-size distribution which is singular at zero and quantum size effects may be responsible for these phenomena. From our scaling analysis of the relations between resistivity, and the ordinary and extraordinary Hall effects, it follows that the extraordinary Hall resistivity rho(xys) scales with mobility as-rho(xys)proportional to mu(-gamma) with the exponent gamma approximate to 0.5, which is characteristically different from the predictions of both the skew scattering (gamma approximate to 1) and the side jump (gamma approximate to 2) theories in homogeneous ferromagnets