The development of semiconductor-based photoelectrocatalysts with superior activity is of great importance for water purification. Here, we fabricated graphene oxide (GO)-wrapped Ti/PbO
2
photoanodes ...by combination of electrochemical deposition and electrophoretic deposition process. The as-obtained composite electrodes showed better performance for photoelectrocatalytic (PEC) degradation of reactive brilliant blue KN-R, as compared with that of Ti/PbO
2
reference. Experimental results demonstrated that the efficient PEC performance of graphene oxide (GO)-wrapped Ti/PbO
2
photoanodes could be ascribed to the low charge transfer resistance, large electrochemical active areas, and high separation efficiency of induced electrons/holes. Furthermore, a significant photoelectric synergy effect can be observed for the graphene oxide (GO)-wrapped Ti/PbO
2
photoanodes during the photoelectrocatalytic process.
Although the Ostwald ripening approach is often utilized to manufacture single hollow metal oxide, constructing hollow binary oxide heterostructures as potent photoelectrochemical (PEC) catalysts is ...still obscure and challenging. Herein, we reveal a general strategy for fabricating hollow binary oxides heterostructures (Co3O4-δ-MnO2 and Co3O4–SnO2) utilizing Ostwald ripening. Hollow Co3O4-δ-MnO2 nano-network with the structure evolution process was systematically explored through experimental and theoretical tools, identifying the origin of hollow binary oxides due to the interfaces acting as landing sites for their growth. In addition, the structural evolution, from hollow Co3O4-δ-MnO2 to Co3O4-α-MnO2, can be observed when the time of secondary hydrothermal reaches 96 h due to the topotactic layer-to-tunnel transition process. Notably, optimized Co3O4-δ-MnO2-48 exhibits a superior PEC degradation efficiency of 96.42% and excellent durability (20,000 min) under harsh acid conditions, attributed to the massive hollow structures' vast surface area for high intently active species. Furthermore, density functional theory simulations elucidated the Co3O4-δ-MnO2’ electron-deficient surface and high d-band center (Co3O4-δ-MnO2, -1.06; Co3O4-α-MnO2, -1.49), strengthening the interaction between the catalyst's surface and active species and prolonging the lifetime of active species of •O2− and 1O2. This work not only demonstrates superior PEC degradation efficiency of hollow Co3O4-δ-MnO2 for practical use but also lays the cornerstone for constructing hollow binary oxides heterostructures through Ostwald ripening.
Constructing hollow binary oxide heterostructures as effective photoelectrochemical (PEC) catalysts remains ambiguous and challenging. We reveal a general strategy for fabricating hollow binary oxide heterostructures. Especially, Co3O4-δ-MnO2-48 exhibit a superior PEC degradation efficiency of 96.42% and excellent durability, attributed to the massive hollow structures' vast surface area for highly intently active species. Display omitted
The gonad of jellyfish (
), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral ...protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptides were characterized with HPLC-MS/MS. One peptide with amino acid sequence Ser-Tyr (SY) was identified and synthesized, which showed good ACE inhibitory and antioxidant activity. The IC
of this peptide on DPPH, ·OH, super oxygen anion scavenging activities, and ACE inhibitory activity are 84.623 μM, 1177.632 μM, 456.663 μM, and 1164.179 μM, respectively. The anchor in the binding site of SY and ACE C-domain (ACE-C) was obtained by molecular simulations. The results showed that the dipeptide purified from jellyfish gonad protein hydrolysates can be used as functional food material and is helpful in the study of antioxidant and inhibition of ACE.
Herein, a novel Ti/black TiO
2
-PbO
2
micro/nanostructured photoanode with tunable hydrophobic/hydrophilic characteristics was fabricated via the facile hydrothermal strategy. The tunable ...hydrophobic/hydrophilic feature of black TiO
2
/PbO
2
architecture is realized by changing loadings of flower-like PbO
2
microspheres. Interestingly, the density functional theory (DFT) calculations demonstrated that H
2
O molecules prefer to adsorb on the surface of black TiO
2
nanosheets, and easier to form hydroxyl radicals on the surface of PbO
2
. Thus, a cooperation action between black TiO
2
and PbO
2
regarding the generation of hydroxyl radical (·OH) by water photoelectrolysis occurs as follows: the black TiO
2
nanosheet layer can be acted as the supply station of water and rapidly transfer the water molecules to neighboring PbO
2
(acted as generation center of hydroxyl radical) to generate hydroxyl radical. Obviously, the division of labor and cooperation between black TiO
2
and PbO
2
is helpful to improve the generation efficiency of hydroxyl radical. Furthermore, the constructed black TiO
2
-PbO
2
architectures have large electroactive areas, low charge transfer resistance, and high separation efficiency of induced carriers. The black TiO
2
-PbO
2
micro/nanostructure obtained under optimum conditions (Ti/black TiO
2
-PbO
2
-180 min) has the highest PEC removal rate of dye (86.24%); an enhancement of approximate 30% is achieved as compared with that of pure black TiO
2
(65.20%). These new findings not only make Ti/black TiO
2
-PbO
2
a more attractive photoanode but, most significantly, also provide promising strategy for designing photoanode.
Graphical abstract
A novel Ti/black TiO
2
-PbO
2
micro/nanostructured photoanode with tunable hydrophobic/hydrophilic characteristics was fabricated via the facile hydrothermal strategy. The tunable hydrophobic/hydrophilic feature of black TiO
2
/PbO
2
architecture is realized by changing loadings of flower-like PbO
2
microspheres. Interestingly, the density functional theory (DFT) calculations demonstrated that H
2
O molecules prefer to adsorb on the surface of black TiO
2
nanosheets, and easier to form hydroxyl radicals on the surface of PbO
2
. Thus, a cooperation action between black TiO
2
and PbO
2
regarding the generation of hydroxyl radical (·OH) by water photoelectrolysis occurs as follows: the black TiO
2
nanosheet layer can be acted as the supply station of water and rapidly transfer the water molecules to neighboring PbO
2
(acted as generation center of hydroxyl radical) to generate hydroxyl radical. Obviously, the division of labor and cooperation between black TiO
2
and PbO
2
is helpful to improve the generation efficiency of hydroxyl radical. Furthermore, the constructed black TiO
2
-PbO
2
architectures have large electroactive areas, low charge transfer resistance, and high separation efficiency of induced carriers. Thus, the black TiO
2
-PbO
2
micro/nanostructured photoanode exhibited higher photoelectrochemical (PEC) activity, better reproducibility, and obvious photoelectric synergism for the decolorization of dye (reactive brilliant blue KN-R aqueous solution), as compared with black TiO
2
.
Ion doping is regarded as an effective method to improve the intrinsic properties of semiconductor photoanode. In this paper, Bi-doped Ti/Co
3
O
4
NWs with n-type characteristics were prepared by ...one-step hydrothermal method and applied into photoelectrocatalystic (PEC) decolorization of dyeing wastewater (reactive brilliant blue KN-R). By adjusting the content of bismuth, the performance of the Ti/Co
3
O
4
NWs can be optimized, and the physicochemical properties of as-obtained electrodes were also characterized by XRD, TEM, SEM, XPS, EDS and so on. It is found that the Bi doping can tune the morphology of Ti/Co
3
O
4
NWs, and enhance the PEC activity of Ti/Co
3
O
4
NWs. Furthermore, the Bi-doped Ti/Co
3
O
4
electrode exhibited obvious photoelectric synergism and good reproducibility. The improvement of PEC performance for Bi-doped Ti/Co
3
O
4
NWs can be ascribed to its higher efficiency of generating hydroxyl radical, better conductivity and more active sites.
Reasonable hydrophobic anode is deemed to be a promising electrode for photoelectrocatalytic degradation of wastewater. In this study, the C
3
N
4
-modified Ti/PbO
2
electrode with tunable ...hydrophobic characteristics is fabricated by a facile electrodeposition process. It is found that the introduction of C
3
N
4
into the PbO
2
films changed the morphology, surface hydrophilicity, and hydrophobicity of the electrode, which promotes the photoelectrochemical active areas, generating efficiency of hydroxyl radicals. In addition, introducing C
3
N
4
into PbO
2
coating can enhance oxygen evolution potential and carrier density of PbO
2
. Photoelectrocatalytic degradation experiments show that the addition of C
3
N
4
can further improve the catalytic performance of PbO
2
and there exists a significant photoelectric synergism in photoelectrocatalytic process. These results demonstrate that the combination of reasonable surface hydrophobic characteristics and photoelectrocatalytic is a prospective approach for wastewater treatment.
It is a challenge to degrade sulfated polysaccharides without stripping sulfate groups. In the present study, a photocatalytic method was applied to degrade fucoidan, a sulfated polysaccharide from ...brown algae. The degradation with varying addition amounts of H
O
and TiO
were monitored by high performance gel permeation chromatography (HPGPC) and thin layer chromatography (TLC), and fucoidan was efficiently degraded with 5% TiO
and 0.95% H
O
. A comparison of the chemical compositions of 2 products obtained after 0.5 h and 3 h illumination, DF-0.5 (average Mw 90 kDa) and DF-3 (average Mw 3 kDa), respectively, with those of fucoidan indicates the photocatalytic degradation did not strip the sulfate groups, but reduced the galactose/fucose ratio. Moreover, 12 oligosaccharides in DF-3 were identified by HPLC-ESI-MS
and 10 of them were sulfated. In addition, DF-0.5 showed anticoagulant activity as strong as fucoidan while DF-3 could specifically prolong the activated partial thromboplastin time. All samples exerted inhibition effects on the intrinsic pathway FXII in a dose-dependent manner. Thus, photocatalytic degradation demonstrated the potential to prepare sulfated low-molecular-weight fucoidan with anticoagulant activity.
Low-molecular-weight carrageenan has attracted great interest because it shows advantages in solubility, absorption efficiency, and bioavailability compared to original carrageenan. However more ...environment-friendly and efficient methods to prepare low-molecular-weight carrageenan are still in great need. In the present study, a photocatalytic degradation method with only TiO
has been developed and it could decrease the average molecular weight of κ-carrageenan to 4 kDa within 6 h. The comparison of the chemical compositions of the degradation products with those of carrageenan by FT-IR, NMR, etc., indicates no obvious removement of sulfate group, which is essential for bioactivities. Then 20 carrageenan oligosaccharides in the degradation products were identified by HPLC-MS
, and 75% of them possessed AnGal or its decarbonylated derivative at their reducing end, indicating that photocatalysis is preferential to break the glycosidic bond of AnGal. Moreover, the analysis results rheology and Cryo-SEM demonstrated that the gel property decreased gradually. Therefore, the present study demonstrated that the photocatalytic method with TiO
as the only catalyst has the potential to prepare low-molecular-weight carrageenan with high sulfation degree and low viscosity, and it also proposed the degradation rules after characterizing the degradation products. Thus, the present study provides an effective green method for the degradation of carrageenan.
Calcium is known as an essential nutrient in the human body. Insufficient calcium uptake results in metabolic bone disease such as rickets in children and osteoporosis in the elderly. Chelated ...calcium has been proposed as a superior candidate to ionized calcium for improving calcium absorption and bioavailability and might have potential application in the management of calcium deficiencies for human beings.
A number of calcium chelating peptides with the ability to enhance calcium absorption and bioavailability have been discovered and characterized. This review outlines the sources of food-derived calcium chelating peptides, and focuses on the peptide-calcium chelating mode as well as calcium absorption and bioavailability enhancement potential of calcium chelating peptides.
Calcium chelating peptides have been identified from different food sources, including animal sources, aquatic sources and plant sources. These peptides could chelate with calcium via specific groups, such as phosphate group or carboxyl group. Furthermore, some peptides such as casein phosphopeptides (CPPs) and soybean peptides, have been reported to improve intestinal calcium absorption by in vitro cell models and increase incorporation of calcium into bones by rat models. Currently, with more and more calcium chelating peptides being discovered and characterized from different food sources, more data on the peptide-calcium chelating mode and the effect of peptides on calcium absorption and bioavailability, as is the case with CPPs, would be of particular value for their incorporation as functional ingredients or calcium supplements.
•Calcium chelating peptides have potential for the management of calcium deficiencies.•Calcium-chelating peptides were isolated and characterized from various sources.•The peptide-calcium chelating modes were outlined.•The effect of peptides on calcium absorption and bioavailability was discussed.•Future trends in the study of calcium-chelating peptides were put forward.
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