Topotactic synthesis of high-entropy sulfide nanosheets as efficient pre-catalysts for water oxidation.

Herein, quinary CoFeNiCuCr sulfide nanosheets with a high-entropy feature and rough surface were fabricated via a topotactic transformation pathway from high-entropy layered metal hydroxides, and display facile pre-oxidation and improved intrinsic activity towards the robust oxygen evolution reaction.

Lattice-disordered high-entropy metal hydroxide nanosheets as efficient precatalysts for bifunctional electro-oxidation.

Electro-oxidation reactions (EORs) are important half reactions in overall and assisted water electrolysis, which are crucial in achieving economic and sustainable hydrogen production and realizing simultaneous wastewater treatment. Current studies indicate that the high-valence metal ions that are locally enriched in the catalysts or generated in situ during the anodic preoxidation process are active species for EORs. Hence, designing (pre)catalysts with enriched local active sites and boosted preoxidation is of great importance. In this work, with a focus on improving the EOR performance toward the oxygen evolution reaction (OER) and the urea oxidation reaction (UOR), we fabricated a lattice-disordered high-entropy FeCuCoNiZn hydroxide nanoarray catalyst that exhibits robust bifunctional OER and UOR behavior. The high-entropy feature could bring in a unique catalytic ensemble effect and remarkably improve the intrinsic OER/UOR activity. The lattice-disordered structure could not only enrich the local high-valence metal ions as active sites but also provide abundant reactive surface sites to accelerate the preoxidation process, thus leading to enriched active sites for the OER and UOR. Benefitting from the structural merits, the lattice-disordered high-entropy catalyst exhibits excellent OER and UOR activity with low overpotential, large current density and enhanced intrinsic activity, and no performance degradation but dramatic 35.3% and 88.7% enhancement in activity can be achieved during the long-term OER and UOR tests, respectively. The robust OER and UOR performance makes the lattice-disordered high-entropy catalyst a promising candidate for overall and urea-assisted water electrolysis from industrial, agricultural and sanitary wastewater.

Dual-oxidation-induced lattice disordering in a Prussian blue analog for ultrastable oxygen evolution reaction performance.

Enriching the active sites and enhancing the intrinsic activity of a single site are two basic strategies for improving the activity toward the electrocatalytic oxygen evolution reaction (OER), and designing an advanced microstructure with a boosted pre-oxidation process can further guarantee durability toward long-term catalysis. Herein, we propose a dual oxidation strategy of a Co Prussian blue analog (Co PBA), which simultaneously achieves Co3+ active site enrichment, in situ CeO2 decoration and lattice disordering with abundant undercoordinated sites, realizing highly efficient and ultrastable OER performance. The dual oxidation process can induce the enrichment of high-valence Co ions by combined chemical oxidation and d-f electron coupling compared to the singly oxidized catalysts, thereby providing more active sites with enhanced intrinsic activity for the early triggered OER process. In addition, the disordered lattice can provide abundant reactive Co sites for the pre-oxidation process, thereby leading to obvious activation of the catalysts and remarkable operational stability due to the substantially accumulated Co3+ sites. Benefitting from the structural advantages of lattice-disordered dual-oxidized Co PBA nanocages, a low overpotential of 240 mV can be achieved for a 10 mA cm-2 current density, and the large catalytic current density and intrinsic activity are among the best compared to those of previously reported PBA-based and PBA-derived catalysts and even RuO2 and IrO2. In addition, ultrastable OER behavior with a 263 % activity enhancement in 150 h can result, making the dual-oxidized catalyst a promising candidate for water electrolysis.

Sodium acetate/sodium butyrate alleviates lipopolysaccharide-induced diarrhea in mice via regulating the gut microbiota, inflammatory cytokines, antioxidant levels, and NLRP3/Caspase-1 signaling.

Diarrhea is a word-widely severe disease coupled with gastrointestinal dysfunction, especially in cattle causing huge economic losses. However, the effects of currently implemented measures are still not enough to prevent diarrhea. Previously we found that dropped short-chain fatty acids in diarrhea yaks, and butyrate is commonly known to be related to the epithelial barrier function and intestinal inflammation. However, it is still unknown whether sodium acetate/sodium butyrate could alleviate diarrhea in animals. The present study is carried out to explore the potential effects of sodium acetate/sodium butyrate on lipopolysaccharide-induced diarrhea in mice. Fifty ICR mice were randomly divided into control (C), LPS-induced (L), and sodium acetate/sodium butyrate (D, B, A)-treated groups. Serum and intestine samples were collected to examine inflammatory cytokines, antioxidant levels, relative gene expressions via real-time PCR assay, and gut microbiota changes through high-throughput sequencing. Results indicated that LPS decreased the villus height (p < 0.0001), increased the crypt depth (p < 0.05), and lowered the villus height to crypt depth ratio (p < 0.0001), while sodium acetate/sodium butyrate supplementation caused a significant increase in the villus height (p < 0.001), decrease in the crypt depth (p < 0.01), and increase in the villus height to crypt depth ratio (p < 0.001), especially. In mice treated with LPS, it was found that the serum level of IL-1ß, TNF-α (p < 0.001), and MDA (p < 0.01) was significantly higher; however, sodium acetate/sodium butyrate supplementation significantly reduced IL-1ß (p < 0.001), TNF-α (p < 0.01), and MDA (p < 0.01), respectively. A total of 19 genera were detected among mouse groups; LPS challenge decreased the abundance of Lactobacillus, unidentified F16, unidentified_S24-7, Adlercreutzia, Ruminococcus, unclassified Pseudomonadales, [Ruminococcus], Acetobacter, cc 1, Rhodococcus, unclassified Comamonadaceae, Faecalibacterium, and Cupriavidus, while increased Shigella, Rhodococcus, unclassified Comamonadaceae, and unclassified Pseudomonadales in group L. Interestingly, sodium acetate/sodium butyrate supplementation increased Lactobacillus, unidentified F16, Adlercreutzia, Ruminococcus, [Ruminococcus], unidentified F16, cc 115, Acetobacter, Faecalibacterium, and Cupriavidus, while decreased Shigella, unclassified Enterobacteriaceae, unclassified Pseudomonadales, Rhodococcus, and unclassified Comamonadaceae. LPS treatment upregulated the expressions of ZO-1 (p < 0.01) and NLRP3 (p < 0.0001) genes in mice; however, sodium acetate/sodium butyrate solution supplementation downregulated the expressions of ZO-1 (p < 0.05) and NLRP3 (p < 0.05) genes in treated mice. Also, the LPS challenge clearly downregulated the expression of Occludin (p < 0.001), Claudin (p < 0.0001), and Caspase-1 (p < 0.0001) genes, while sodium acetate/sodium butyrate solution supplementation upregulated those gene expressions in treated groups. The present study revealed that sodium acetate/sodium butyrate supplementation alleviated LPS-induced diarrhea in mice via enriching beneficial bacterium and decreasing pathogens, which could regulate oxidative damages and inflammatory responses via NLRP3/Caspase-1 signaling. The current results may give insights into the prevention and treatment of diarrhea.

Oriented interlayered charge transfer in NiCoFe layered double hydroxide/MoO3 stacked heterostructure promoting the oxygen-evolving behavior.

Oxygen evolution reaction (OER), the rate-limiting half reaction of water electrolysis, plays as a crucial role in improving the overall efficiency of the coupled hydrogen evolution. To date, earth-abundant OER catalysts have been extensively studied, while unfortunately their catalytic activity and operational stability still need to be further optimized. In this work, we fabricated a highly efficient OER catalyst based on two-dimensional (2D) NiCoFe layered double hydroxide (LDH)/MoO3 stacked heterostructure with enriched active sites and optimal electronic structure via an electrostatic-driven self-assembly process. The rough surface of the 2D heterostructure could offer abundant reactive sites for the pre-oxidation reaction, thereby leading to fast generation of the high-valence active species for OER, and the multi-metal synergy and oriented interlayered charge transfer could further enhance the intrinsic OER activity, finally resulting in enhanced OER performance with low overpotential, large current density, high intrinsic activity and excellent operational stability.

Cerium-induced lattice disordering in Co-based nanocatalysts promoting the hydrazine electro-oxidation behavior.

In this work, cerium-incorporated Co-based catalysts encapsulated in nitrogen-doped carbon were fabricated for the electrocatalytic hydrazine oxidation reaction (HzOR). The Ce incorporation could lead to the formation of surface oxide nanolayers with a disordered lattice, endowing the catalyst with enriched active sites and enhanced intrinsic activity for promoted HzOR.

Cobalt, iron co-incorporated Ni(OH)2 multiphase for superior multifunctional electrocatalytic oxidation.

The cobalt, iron co-incorporated Ni(OH)2 multiphase displays superior catalytic activity and stability for multifunctional electrocatalytic oxidation, ascribed to the multiphase synergy, enhanced charge transfer and well-exposed active sites.

Green preparation of porous hierarchical TiO2(B)/anatase phase junction for effective photocatalytic degradation of antibiotics.

In this study, porous hierarchical bronze/anatase phase junction TiO2 assembled by ultrathin two-dimensional nanosheets was prepared by a novel, green and simple deep eutectic solvent-regulated strategy. Due to its structural features, the TiO2 sample exhibited enhanced photocatalytic activities for multiple kinds of antibiotics, including ofloxacin, ciprofloxacin and chloramphenicol.

"Pit-dot" ultrathin nanosheets of hydrated copper pyrophosphate as efficient pre-catalysts for robust water oxidation.

Herein, hydrated copper pyrophosphate ultrathin nanosheets with a unique "pit-dot" nanostructure were fabricated as efficient pre-catalysts for the oxygen evolution reaction, and systematic post-catalytic characterization studies confirmed the important role of the boosted pre-oxidation reaction in promoting the OER catalysis.

Lanthanum-incorporated ß-Ni(OH)2 nanoarrays for robust urea electro-oxidation.

Lanthanum-incorporated ß-Ni(OH)2 nanosheets display superior catalytic behavior and stability for urea electro-oxidation, which originates from the optimized electronic structure, the downshift of the d-band center and the increased number of exposed active sites.

In-plane ß-Co(OH)2/Co3O4 hybrid nanosheets for flexible all-solid-state thin-film supercapacitors with high electrochemical performance.

With the increasing demand for portable electronic devices, efficient power supplies with ultraflexibility have received considerable attention, among which the all-solid-state thin-film supercapacitors (ASSTFSs) have been considered as promising candidates for powering the portable devices with high performance and safety. In this work, we proposed in-plane ß-Co(OH)2/Co3O4 hybrid nanosheets with porous surface and controllable composition, which could be assembled as flexible electrodes for ASSTFSs. As the two-dimensional (2D) matrix of the hybrid nanosheets, the porous ß-Co(OH)2 component could offer a large surface area, thereby exposing more surface sites for surface redox reactions; the conductive Co3O4 component could effectively improve the intrinsic conductivity of the electrode material, thereby realizing good electrochemical performance synergistically. With the merits of the synergistic structural benefits, the ASSTFS device based on the ß-Co(OH)2/Co3O4 hybrid nanosheets exhibits high specific capacitance with good cycling stability and ultraflexibility, making our device an outstanding candidate for practical power supply in electronic devices.

Controllable fabrication of TiO2 anatase/rutile phase junctions by a designer solvent for promoted photocatalytic performance.

Herein, novel coin tree-like TiO2 moieties with lots of anatase-rutile phase junctions were constructed by a general, simple, and environmentally friendly strategy. The anatase/rutile ratios can be easily tuned by changing the ratios of the two H-bond donors. Owing to this featured shape, the TiO2 sample displays robust photocatalytic activity and better stability.

A molten-salt protected pyrolysis approach for fabricating a ternary nickel-cobalt-iron oxide nanomesh catalyst with promoted oxygen-evolving performance.

In this work, a highly porous ternary NiCoFe oxide nanomesh with two-dimensional morphology and quasi-single-crystalline (QSC) feature was synthesized via a convenient molten-salt protected pyrolysis approach, which achieves remarkable OER performance with a low overpotential, high current density, improved intrinsic activity and superior operational stability.

Modulation of crystal water in cobalt phosphate for promoted water oxidation.

Herein, low-dimensional cobalt phosphate (Co-Pi) catalysts with variable contents of crystal water were fabricated for oxygen evolution reaction (OER). Owing to the optimized electronic structure, rich surface sites and favorable charge transport ability, Co-Pi tetrahydrate exhibits remarkable OER activity with a low overpotential, large current density and high intrinsic activity, and it is proved to be the optimal Co-Pi phase for OER.

An iron incorporation-induced nickel hydroxide multiphase with a 2D/3D hierarchical sheet-on-sheet structure for electrocatalytic water oxidation.

An Fe-incorporated Ni(OH)2 multiphase with a unique 2D/3D hierarchical sheet-on-sheet structure exhibits superior catalytic activity and durability for water oxidation, which is contributed by synergistic effects, enhanced electron transport and an increased number of exposed active sites.

Modified bluing treatment to produce nickel-cobalt-iron spinel oxide with promoted oxygen-evolving performance.

A rapid modified bluing treatment approach was proposed for the facile synthesis of a ternary NiCoFe spinel oxide catalyst. Benefitted from the synergy of multi-elements, the enriched high-valence species and good structural stability, highly efficient and durable oxygen-evolving performance was achieved, offering an economic route for the batch preparation of advanced electrocatalysts.

Promoted water splitting by efficient electron transfer between Au nanoparticles and hematite nanoplates: a theoretical and experimental study.

An ideal interface model combining a hematite nanoplate-based photoanode with Au nanoparticles (NPs) is proposed for elucidating the specific role of Au NPs in photoelectrochemical performances. The theoretical and experimental results reveal that Au/Fe2O3 nanoplates can lead to an enhanced localized electric field at the metal-semiconductor interface upon the formation of surface plasmon resonance and hot electrons, which can be injected into the conduction band of the semiconductor, thus improving the efficiency of the generation and separation of electron-hole pairs. As expected, the Au/Fe2O3 nanoplate-based photoelectrode possessed a higher carrier density and a photocurrent of 1.7 mA cm-2 and 3.8 mA cm-2 at 1.23 V and 1.5 V vs. RHE, which are nearly 5 times and 30 times larger than that of the Au/Fe2O3 nanocrystals and pristine Fe2O3 nanoplate-based photoelectrodes, respectively.

Synthesis, Photophysical Properties and Two-Photon Absorption Study of Tetraazachrysene-based N-Heteroacenes.

Three novel N-heteroacene molecules (SDNU-1, SDNU-2 and SDNU-3) based on tetraazachrysene units as cores have been designed, synthesized and fully characterized. Their photophysical, electrochemical and fluorescence properties were investigated, and they exhibited blue to green emission in the solid state. Interestingly, SDNU-2 exhibited high solid photoluminescence quantum efficiencies (75.3 %), which is the highest value of N-heteroacenes derivatives to date. Two-photon absorption studies have been conducted by using the open and close aperture Z-san technique. SDNU-3 showed a significant enhancement in the two-photon absorption cross-section with magnitudes as high as about 700 GM (1 GM=1×10-50  cm4 s/photon) when excited with 800 nm light, which is the largest value based on a heteroacene system measured by using a Z-scan experiment so far. We attribute the outcome to sufficient electronic coupling between the strong charge transfer of quadrupolar substituents and the tetraazachrysene core. Our result would provide a new guideline to design novel efficient two-photon materials based on N-heteroacene cores.

Morphology and electronic structure modulation induced by fluorine doping in nickel-based heterostructures for robust bifunctional electrocatalysis.

Fabrication of advanced electrocatalysts with high activity and durability is urgently needed to achieve energy conversion and pollution treatment at the same time. Herein, we highlight a fluorine-doped nickel-based heterostructure, in which fluorine doping displays a dual effect in Ni(OH)2 nanosheets/Ni3S2 heteronanorods. On the one hand, fluorine doping can facilitate the formation of Ni(OH)2 nanosheets/Ni3S2 heteronanorods through one-step in situ growth on nickel foams. The unique heterostructure enables good exposure of abundant active sites and highly active heterointerfaces. On the other hand, the uniform incorporation of fluorine can effectively modulate the electron density at the Fermi level of Ni3S2, contributing to the improved electrical conductivity and charge transfer efficiency, further improving the electrocatalytic activity in the oxygen evolution reaction (OER) and urea oxidation reaction (UOR). The optimal heterostructure presents a low overpotential of 360 mV to reach the OER current density of 100 mA cm-2. Finally, this heterostructure also displays a superior UOR anodic peak current of about 322.9 mA cm-2, almost the highest value at the anodic peak compared to the literature.

Iron-Incorporated α-Ni(OH)2 Hierarchical Nanosheet Arrays for Electrocatalytic Urea Oxidation.

An iron-incorporated α-Ni(OH)2 nanosheet array catalyst characterized by hierarchical surface nanobelts and robust urea oxidation performance are reported. The unique single-crystalline belt-on-sheet hierarchical nanostructure was identified and it endows more reactive edges for the Ni2+ -to-Ni3+ pre-oxidation process to boost the generation of active high-valence species for the urea oxidation reaction (UOR). Benefitting from the optimal Fe concentration, the UOR activity was further optimized owing to the favorable reaction kinetics. With the synergistic benefits of the increased surface areas, improved charge transfer behavior, favorable reaction kinetics and excellent structural stability, the iron-incorporated α-Ni(OH)2 hierarchical nanosheet array catalyst displays significantly improved UOR performance with both high activity and outstanding operational stability. This work could guide the design of advanced UOR catalysts for wastewater treatment and clean energy production in the future.