ABSTRACT
Highly active and robust Pt-based electrocatalysts for an oxygen reduction reaction (ORR) are of crucial significance for the development of proton exchange membrane fuel cells (PEMFCs). Herein, the high-loading and well-dispersive Pt clusters on graphitic carbon-supported CeO2 with abundant oxygen vacancies (PtAC/CeO2-OV@GC) were successfully fabricated by a molten-salt electrochemical-assisted method. The bonding of Pt with the highly electronegative O induces charge redistribution through the Pt-O-Ce structure, thus reducing the adsorption energies of oxygen-containing species. Such a PtAC/CeO2-OV@GC electrocatalyst exhibits a greatly enhanced ORR performance with a mass activity of 0.41 ± 0.02 A·mg-1Pt at 0.9 V versus a reversible hydrogen electrode, which is 2.7 times the value of a commercial Pt/C catalyst and shows negligible activity decay after 20000 cycles of accelerated degradation tests. It is anticipated that this work will provide enlightening guidance on the controllable synthesis and rational design of high-performance Pt-based electrocatalysts for PEMFCs.
ABSTRACT
The development of low-cost single-atom electrocatalysts for oxygen reduction reaction (ORR) is highly desired but remains a grand challenge. Superior to the conventional techniques, a microwave-assisted strategy is reported for rapid production of high-quality Fe/N/C single-atom catalysts (SACs) with profoundly enhanced reaction rate and remarkably reduced energy consumption. The as-synthesized catalysts exhibit an excellent ORR performance with a positive half-wave potential up to 0.90 V, a high turnover frequency of 0.76 s-1 , as well as a satisfied stability with a lost half-wave potential of just 27 mV over 9000 cycles (much better than that of Pt/C with 107 mV lost) and good methanol resistance. The open-circuit voltages of as-constructed aqueous and flexible all-solid-state Zn-air batteries (ZABs) are 1.56 and 1.52 V, respectively, higher than those of 20% Pt/C-based ones (i.e., 1.43 and 1.38 V, respectively). Impressively, they afford a peak power density of 235 mW cm-2 , which exceeds that of Pt/C (i.e., 186 mW cm-2 ), and is comparable to the best ones of Fe/N/C-based ZABs ever reported.
ABSTRACT
Objective: Heme oxygenase (HO) has been shown to have important antioxidant and anti-inflammatory properties, resulting in a vascular antitherogenic effect. This study was undertaken to evaluate the role of HO-2 in atherosclerosis. Method and results: The expression levels of HO-2 were evaluated in M1 and M2 bone marrow macrophage induced by LPS and IL4. The expression of HO-2 was significantly higher in M2 macrophage than in M1 macrophage. Western diet (WD) caused a significant increase in HO-2 expression in ApoE-/- mice. The adeno-associated viral (AAV) vectors expressing HO-2 was constructed, and the mice were received saline (ApoE-/-), AAV (ApoE-/-), AAV-HO-2 (ApoE-/-) on WD at 12 weeks and their plasma lipids, inï¬ammatory cytokines, atherosclerosis were evaluated for 16 weeks. The results showed AAV-HO-2 was robust, with a significant decrease in the en face aortas, lipids levels, inï¬ammatory cytokines and M1 macrophage content in AAV-HO-2 ApoE-/- compared to control AAV-ApoE-/-. Conclusion: HO-2 expression in macrophages plays an important role of the antiatherogenic effect, decreasing the inflammatory component of atherosclerotic lesions. These results suggest that HO-2 may be a novel therapeutic target for cardiovascular diseases.
ABSTRACT
Currently, two-dimensional/two-dimensional (2D/2D) van der Waals heterojunctions, as novel and excellent candidates for photocatalysts, have attracted significant attention because of their fundamentally improved interfacial charge separation/transfer and massive reactive centers. Herein, novel 2D/2D Ta3N5-nanosheet/ReS2-nanosheet van der Waals heterojunction photocatalysts are rationally designed through a method combining template-assisted and solution-adsorption processes. The resultant heterojunctions exhibit enhanced interfacial charge transfer, boosted light absorption and significantly increased reaction sites for hydrogen evolution. Correspondingly, they deliver a high photocatalytic hydrogen production activity of 615 µmol g-1 h-1, which is â¼3 and â¼12 times greater than that of bare Ta3N5 nanosheets and ReS2 nanosheets, respectively, and superior to those in the most recent reports about photocatalytic water splitting on Ta3N5 material, implying their potential applications as advanced catalysts for hydrogen evolution.
ABSTRACT
Atherosclerosis, a chronic inflammatory disease that often leads to myocardial infarction and stroke, is mainly caused by lipid accumulation. Eukaryotic initiation factor 6 (Eif6) is a rate-limiting factor in protein translation of transcription factors necessary for lipogenesis. To determine whether Eif6 affects atherosclerosis, Eif6+/- mice were crossed into Apoe-/- background. Apoe-/-/Eif6+/- mice on high fat diet showed significant reduction in atherosclerotic lesions and necrotic core content in aortic root sections in comparison with Apoe-/- mice. RNA-Seq was used to investigate the effect of Eif6 in aorta. Deficiency of Eif6 shows broad effect on cell metabolism. Expression of genes for fatty acid synthesis including Fatty acid synthase (Fasn), Elovl3, Elovl6 and Acaca are down-regulated in aortas. Importantly, Fasn is decreased in macrophages. Results suggest that Eif6 deficiency may decrease atherosclerosis through inhibition of Fasn and lipids metabolism in macrophages.
Subject(s)
Atherosclerosis , Mice , Animals , Mice, Knockout, ApoE , Atherosclerosis/metabolism , Macrophages/metabolism , Fatty Acid Synthases/genetics , Fatty Acid Synthases/metabolism , Apolipoproteins E/genetics , Apolipoproteins E/metabolism , Mice, Inbred C57BL , Mice, Knockout , Disease Models, AnimalABSTRACT
Photocatalytic CO2 reduction by solar energy into carbonaceous feedstock chemicals is recognized as one of the effective ways to mitigate both the energy crisis and greenhouse effect, which fundamentally relies on the development of advanced photocatalysts. Here, the exploration of porous microrod photocatalysts based on novel NiCoO solid solutions derived from bimetallic metal-organic frameworks (MOFs) is reported. They exhibit overall enhanced photocatalytic performance with both high activity and remarkable selectivity for reducing CO2 into CO under visible-light irradiation, which are superior to most related photocatalysts reported. Accordingly, the Ni0.2 -Co0.8 -O microrod (MR-N0.2 C0.8 O) photocatalyst delivers high efficiency for photocatalytic CO2 reduction into CO at a rate up to ≈277 µmol g-1 h-1 , which is ≈35 times to that of its NiO counterpart. Furthermore, they display a high selectivity of ≈85.12%, which is not only better than that of synthesized Co3 O4 (61.25%) but also superior to that of reported Co3 O4 -based photocatalysts. It is confirmed that the Co and Ni species are responsible for CO2 CO conversion activity and selectivity, respectively. In addition, it is verified, by adjusting the Ni contents, that the band structure of NiCoO microrods can be tailored with favorable reduction band potentials, which thus enhance the selectivity toward CO2 photoreduction.
ABSTRACT
The development of efficient visible-light-driven photocatalysts is one of the critically important issues for solar hydrogen production. Herein, high-efficiency visible-light-driven In2 O3 /CdZnS hybrid photocatalysts are explored by a facile oil-bath method, in which ultrafine CdZnS nanoparticles are anchored on NH2 -MIL-68-derived fusiform In2 O3 mesoporous nanorods. It is disclosed that the as-prepared In2 O3 /CdZnS hybrid photocatalysts exhibit enhanced visible-light harvesting, improves charges transfer and separation as well as abundant active sites. Correspondingly, their visible-light-driven H2 production rate is significantly enhanced for more than 185 times to that of pristine In2 O3 nanorods, and superior to most of In2 O3 -based photocatalysts ever reported, representing their promising applications in advanced photocatalysts.
