No abstract

The design and fabrication of new high-performance electrode materials are critical for driving the development of next-generation energy conversion and energy storage devices.

The development of a high-performance electrocatalyst for oxygen evolution reaction (OER) is imperative but challenging. Here, a partial sulfidation route to construct Ni 2 Fe-LDH/FeNi 2 S 4 heterostructure on nickel foam (Ni 2 Fe-LDH/ FeNi 2 S 4 /NF) by adjusting the hydrothermal duration is reported. The heterostructures afford abundant hydroxide/sulfide interfaces that offer plentiful active sites, rapid charge and mass transfer, favorable adsorption energy to oxygenated species (OH − and OOH) evidenced by the density functional theory calculations, which synergistically boost the alkaline water oxidation. In the 1.0 m KOH solution, Ni 2 Fe-LDH/FeNi 2 S 4 /NF exhibits an excellent OER catalytic activity with a much smaller overpotential (240 mV) to reach the current density of 100 mA cm −2 than single-phase Ni 2 Fe-LDH/NF (279 mV) or FeNi 2 S 4 /NF (271 mV). More impressively, 2000 cycles of cyclic voltammetry scan for water oxidation results in the formation of a sulfate layer over the catalyst. The corresponding post-catalyst demonstrates better OER activity and durability than the initial one in the alkaline simulated seawater electrolyte. The post-Ni 2 Fe-LDH/FeNi 2 S 4 /NF delivers smaller overpotential (250 mV) at 100 mA cm −2 and longer stability time than the original form (260 mV). The post-formed sulfate passivating layer is responsible for the outstanding corrosion resistance of the salty-water oxidation anode since it can effectively repel chloride.

No abstract

In this paper, first-principle calculations based on density functional theory were carried out to explore the interface properties of the hybrid graphene/anatase TiO 2 (001) nanocomposites (G/AT(001)N). The effect of graphene hybridization on energy gap, surface chemical bonding, interfacial charge transfer, and visible light response was investigated in detail. Because of the hybridization of graphene, the band structure of the G/AT(001)N was modified, and the energy gap was reduced to 0.47 eV. Electrons in the bottom of the valence band (VB) of anatase TiO 2 could disperse to the upper part of the VB. And electrons in the upper part of the VB of anatase TiO 2 were likely to be directly excited to graphene under visible light irradiation, which promoted the formation of wellseparated electron−hole pairs. The interfacial electron transfer in the ground electronic state promoted electrons increased on graphene and substantial holes accumulated in TiO 2 (001) facet. Good linkage between TiO 2 (001) facet and graphene could facilitate the charge transfer, promoting photocatalytic efficiency improvement. Hybridization of graphene brought an obvious red shift in the absorption edge and enhanced absorption intensity in the visible region, which indicated the enhancement of photocatalytic performance. The calculation results illustrated the reported experimental observation [J. Phys. Chem. Lett. 2011, 2, 894−899] and would provide new insights into the design of graphene-based semiconductor photocatalysts.

No abstract

Gastrointestinal cancer is currently one of the main causes of cancer death, with a large number of cases and a wide range of lesioned sites. A high fat diet, as a public health problem, has been shown to be correlated with various digestive system diseases and tumors, and can accelerate the occurrence of cancer due to inflammation and altered metabolism. The gut microbiome has been the focus of research in recent years, and associated with cell damage or tumor immune microenvironment changes via direct or extra-intestinal effects; this may facilitate the occurrence and development of gastrointestinal tumors. Based on research showing that both a high fat diet and gut microbes can promote the occurrence of gastrointestinal tumors, and that a high fat diet imbalances intestinal microbes, we propose that a high fat diet drives gastrointestinal tumors by changing the composition of intestinal microbes.

No abstract