The oxygen evolution reaction (OER) in water splitting plays a critical role in some clean energy production systems. Transition-metal oxides as one of the most common OER electrocatalysts have been widely explored; however, their activity is limited by low electrical conductivity, slow mass transfer, and inadequate active sites. Herein, we develop a feasible strategy in which layered two-dimensional metal–organic frameworks (2D MOFs) act as templates to construct metal oxide/carbon (MOx/C, M = Co, Ni, and Cu) nanosheet arrays for the OER. Because of improved conductivity and more exposed active sites afforded by their 2D structures with rich hierarchical pores and the incorporation with porous carbon, these 2D MOF-derived MOx/C arrays present high electrocatalytic activities and good durability. Particularly, Co3O4/CBDC, NiO/CBDC, and Cu2O/S–CTDC exhibit low overpotentials of 208, 285, and 313 mV at the current density of 10 mA cm–2, respectively, outperforming all previously reported corresponding metal oxide-based catalysts.
Constructing stable palladium(II)-based metal–organic frameworks (MOFs) would unlock more opportunities for MOF chemistry, particularly toward applications in catalysis. However, their availability is limited by synthetic challenges due to the inertness of the Pd–ligand coordination bond, as well as the strong tendency of the Pd(II) source to be reduced under typical solvothermal conditions. Under the guidance of reticular chemistry, herein, we present the first example of an azolate Pd-MOF, BUT-33(Pd), obtained via a deuterated solvent-assisted metal metathesis. BUT-33(Pd) retains the underlying sodalite network and mesoporosity of the template BUT-33(Ni) and shows excellent chemical stability (resistance to an 8 M NaOH aqueous solution). With rich Pd(II) sites in the atomically precise distribution, it also demonstrates good performances as a heterogeneous Pd(II) catalyst in a wide application scope, including Suzuki/Heck coupling reactions and photocatalytic CO2 reduction to CH4. This work highlights a feasible approach to reticularly construct noble metal based MOFs via metal metathesis, in which various merits, including high chemical stability, large pores, and tunable functions, have been integrated for addressing challenging tasks.
Abstract. The surface plasmon resonance photocatalysts of Ag-AgBr/RGO were synthesized by chemical precipitation and photochemical reduction method. The samples were characterized by X-ray diffraction and UV-Vis absorption spectroscopy. The photocatalytic activities of catalysts were studied using the photocatalytic degradation of helianthine as a probe reaction. The results showed that the degradation rate of 10 mg/L helianthine reached 95% after 60 min of visible light irradiation.
Parkinson's disease (PD) is accompanied by a complex array of nonmotor and motor manifestations. The exploration of anti-inflammatory and antioxidant active ingredient as potential therapeutic interventions in PD-associated mood alterations has gained significant attention. This study aimed to assess the antidepressant and anxiolytic properties of luteolin (LTN), a potent antioxidant and anti-inflammatory component, using a 6-hydroxydopamine (6-OHDA)-induced animal model of PD. Rats were administered LTN (10, 25, and 50 mg/kg, per oral) and fluoxetine (10 mg/kg/per oral) over a 28-day period. Behavioral tests were employed to estimate the depression- and anxiety-like behaviors. Rats treated with LTN exhibited significant improvement in 6-OHDA-induced mood alterations, as per behavioral tests. Additionally, LTN treatment led to increased hippocampal levels of catalase and superoxide dismutase, and a reduction in malondialdehyde. LTN downregulated the gene expression of nuclear factor kappa B (NF-κB)/nod-like receptor (NLR) pyrin domain-containing 3 (NLRP3) axis components, including NF-κB, NLRP3, ASC, and Caspase1 and reduced the protein level of pro-inflammatory cytokines, including interleukin (IL)-6, interleukin (IL)-1β, and tumor necrosis factor alpha (TNF-α), in addition to augmenting the protein levels of TNF-α, IL-1β, and IL-6. Furthermore, LTN exhibited an upregulatory effect on the anti-inflammatory cytokine IL-10 within the hippocampus of 6-OHDA-induced PD rats. Also, molecular docking showed higher affinity between LTN and NF-κB/NLRP3 axis components. These findings highlight the potential anxiolytic and antidepressant impacts of LTN through its antioxidant and anti-inflammatory mechanisms against 6-OHDA-induced alterations in a rat PD model.
Structural metamorphosis of metal-organic frameworks (MOFs) eliciting highly active metal-hydroxide catalysts has come to the fore lately, with much promise. However, the role of organic ligands leaching into electrolytes during alkaline hydrolysis remains unclear. Here, we elucidate the influence of organic carboxylate anions on a family of Ni or NiFe-based hydroxide type catalysts during the oxygen evolution reaction. After excluding interfering variables, i.e., electrolyte purity, Ohmic loss, and electrolyte pH, the experimental results indicate that adding organic anions to the electrolyte profoundly impacts the redox potential of the Ni species versus with only a negligible effect on the oxygen evolution activities. In-depth studies demonstrate plausible reasons behind those observations and allude to far-reaching implications in controlling electrocatalysis in MOFs, mainly where compositional modularity entails fine-tuning organic anions.
This paper presents an Artificial Brain System of a Maze-like robot, which comprises of a perception unit and decision-making unit. The perception module is based on ART1 neural network, trained to identify the signposts of the maze; decision-making units is based on behavior probability matrix P, and it uses reinforcement learning to update the action strategy. The maze in which the robot would navigate has signposts at every intersection. The signposts are 2-D symbols with noise. In the simulation tests, the robot moves randomly in the maze. By adjusting the vigilance parameter ¿ and reinforcement constant CRF, the robot will eventually pass through the maze after a learning process during the self-exploration. The simulation show that the artificial brain system can be self-organized to make sense of the signposts and successfully guide the robot through the maze.
Because of the problems caused by icing and snow, it is meaningful to develop coatings for anti-icing. In this paper, a superhydrophobic coating was successfully prepared by compounding fluorine-containing acrylate polymer, polysiloxane and nano-SiO 2 . Results of Fourier transform infrared spectroscopy (FT-IR) showed that epoxy groups in fluorine-containing acrylate polymer were partially cross-linked with silanol groups in polysiloxane, while self-crosslinking of silanols dominates the curing reaction. It was proven that there was a positive correlation between water contact angle (WCA) and nano-SiO 2 amount, exhibiting a maximum WCA value of 153.6°. Nevertheless, the superhydrophobic coating is subject to collapse and the nano-particles could be scrubbed away during icing. As a result, the superhydrophobicity had trivial contribution to deicing in this experiment.
With the rapid development of informational construction, higher request is needed by the management of drive-training enterprise.Driving-training school's effective management can reduce the waste of human power and wealth very much, and ensure driving-training school's information resource to be utilized effectively.As the share of human power and information becomes deeper and weeper, the management and share of driving-training school's manager, vehicle and student become more and more important.Present management method' key issues exist as follows.Enrollment, health examination and graduation information of drive-training school students are operated artificially, which is not only with low efficiency but also make mistakes often with many students, vehicle and coaches, distribute of student to coach and coach to vehicle is made artificially.In this way, resource can't be assigned reasonably and used effectively, which are clumsy human usage, unclear of administration responsibility and so on.
The cover picture shows that porous polyhedra NiO was designed and exploited as high-performance water-oxidation electrocatalysts. Benefitting from its porosity and polyhedra structure, such material drives a current density of 10 mA cm−2 with an overpotential of 280 mV, surpassing many reported transition-metal oxides. Additionally, the activity can be kept for at least 20 hours. This work provides a new trial to construct catalyst with more active sites using one of the most abundant metal elements. The cover picture was designed by Shanghai Bantu Culture Media Co., Ltd. More information can be found in the Full Paper by Jian Zhou et al. (DOI: 10.1002/slct.202001471).
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