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1.
J Colloid Interface Sci ; 626: 879-888, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-35835039

RESUMO

Rapid charge recombination in hematite (Fe2O3) during photoelectrochemical water splitting is a major obstacle to achieving high-efficiency photoelectrodes. Surface defect engineering is considered as a viable strategy for enhancing photoelectrochemical activity of oxide photoanodes. Herein, a one-dimensional (1D) defective γ-Fe2O3 nanorods (DFNRs) photoanode is prepared using solvothermal and high-temperature hydrogenation strategies. The as-prepared DFNRs possess superior visible-light absorption capacity and exhibit excellent photoelectrochemical performance (0.98 mA cm-2), with approximately three-fold higher photocurrent density than that of pristine Fe2O3 (FNRs, 0.32 mA cm-2). The enhanced activity of the DFNRs results from the moderate formation of oxygen vacancy defects, which promotes spatial charge separation and transfer at the DFNRs/electrolyte interface, as well as the 1D nanorod structure, which favors rapid charge transfer. The surface of γ-Fe2O3 with hydroxyl (OH) groups provides sufficient surface-active sites. This result suggests that surface-oxygen deficiency of γ-Fe2O3 can not only expand the light absorption range but also facilitating photo-generated charge carriers separation. This surface engineering strategy provides an alternative method for preparing stable and highly active metal oxide photoanodes for photoelectrochemical water splitting.

2.
Nanomaterials (Basel) ; 12(9)2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35564183

RESUMO

Interface engineering is usually considered to be an efficient strategy to promote the separation and migration of photoexcited electron-hole pairs and improve photocatalytic performance. Herein, reduced graphene oxide/mesoporous titanium dioxide nanotube heterojunction assemblies (rGO/TiO2) are fabricated via a facile hydrothermal method. The rGO is anchored on the surface of TiO2 nanosheet assembled nanotubes in a tightly manner due to the laminated effect, in which the formed heterojunction interface becomes efficient charge transfer channels to boost the photocatalytic performance. The resultant rGO/TiO2 heterojunction assemblies extend the photoresponse to the visible light region and exhibit an excellent photocatalytic hydrogen production rate of 932.9 µmol h-1 g-1 under simulated sunlight (AM 1.5G), which is much higher than that of pristine TiO2 nanotubes (768.4 µmol h-1 g-1). The enhancement can be ascribed to the formation of a heterojunction assembly, establishing effective charge transfer channels and favoring spatial charge separation, the introduced rGO acting as an electron acceptor and the two-dimensional mesoporous nanosheets structure supplying a large surface area and adequate surface active sites. This heterojunction assembly will have potential applications in energy fields.

3.
Biol Trace Elem Res ; 165(2): 145-52, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25634140

RESUMO

One hundred and eighty Kunming mice were allotted to three groups in a randomized complete block design, including two treatments and one control. Mice in group 1 were fed a basal diet as control, while mice in groups 2 and 3 were fed the basal diet supplemented with 0.2 mg/kg selenium as sodium selenite (SS) or selenium-chitosan (SC), respectively. On day 28 of the experiment, blood selenium concentration, glutathione peroxidase (GPx) activity, plasma superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and Con A-induced splenocyte proliferation were determined, and plasma interleukin-2 (IL-2) and interferon-γ (IFN-γ) concentrations, splenic plaque-forming cell (PFC) responses, serum hemolysis level (HC50), and delayed-type hypersensitivity (DTH) responses were determined on day 15 of the experiment. The results showed that blood selenium concentration, GPx activity, splenic PFC response, and plasma IL-2 and IFN-γ concentrations in SC group were higher than those in the control and SS groups (P < 0.01 or P < 0.05), respectively. Plasma SOD activity, Serum hemolysis level, DTH responses, and Con A-induced splenocyte proliferation in SC group were higher than those in control (P < 0.01 or P < 0.05). Plasma SOD activity, serum hemolysis level, DTH responses, and Con A-induced splenocyte proliferation in SC group were also higher than those in SS group, while there was no significant difference between SC and SS groups (P > 0.05). Plasma MDA content in SC group was lower than those in the control and SS groups (P < 0.01 or P < 0.05). It is concluded that SC supplement can increase blood selenium concentration, antioxidation status, and cellular and humoral immunity, and SC has better biological activity than SS in mice.


Assuntos
Antioxidantes/metabolismo , Quitosana/química , Imunidade Celular/efeitos dos fármacos , Imunidade Humoral/efeitos dos fármacos , Compostos de Selênio/química , Selênio/sangue , Selenito de Sódio/química , Animais , Proliferação de Células , Eritrócitos/citologia , Feminino , Glutationa Peroxidase/metabolismo , Hemólise , Interferon gama/sangue , Interferon gama/metabolismo , Interleucina-2/sangue , Interleucina-2/metabolismo , Masculino , Camundongos , Distribuição Aleatória , Selênio/química , Ovinos , Baço/citologia , Superóxido Dismutase
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