Photocatalytic organic synthesis needs photocatalysts to initiate the reactions and to control the reaction paths. Available photocatalytic systems rely on electron transfer or energy transfer between the photoexcited catalysts and the substrates. We explore a concept based on the photopromoted catalyst coupling to the substrate and the phototriggered catalyst regeneration by elimination from the catalytic cycle. A catalytic amount of elementary I 2 is applied as both a visible light photocatalyst and a π Lewis acid, enabling the direct activation of alkyne CC bonds for electrophilic cyclization reactions, one of the most important reactions of alkynes. Visible light is crucial for both the iodocyclization of the propargyl amide and the deiodination of the intermediate. Singlet oxygen is found to play a key role in the regeneration of I 2 . This system shows good functional group compatibility for the generation of substituted oxazole aldehydes and indole aldehydes. Hence, this study provides a readily accessible alternative catalytic system for the construction of heterocycle aldehyde derivatives by sunlight photocatalysis.
Developing a conductive catalyst with high catalytic activity is considered to be an effective strategy for improving cathode kinetics of lithium–sulfur batteries, especially at large current density and with lean electrolytes. Lattice‐strain engineering has been a strategy to tune the local structure of catalysts and to help understand the structure–activity relationship between strain and catalyst performance. Here, Co0.9Zn0.1Te2@NC is constructed after zinc atoms are uniformly doped into the CoTe2 lattice. The experimental/theoretical results indicate that a change of the coordination environment for the cobalt atom by the lattice strain modulates the d‐band center with more electrons occupied in antibonding orbitals, thus balancing the adsorption of polysulfides and the intrinsic catalytic effect, thereby activating the intrinsic activity of the catalyst. Benefiting from the merits, with only 4 wt% dosages of catalyst in the cathode, an initial discharge capacity of 1030 mAh g−1 can be achieved at 1 C and stable cycling performances are achieved for 1500/2500 cycles at 1 C/2 C. Upon sulfur loading of 7.7 mg cm−2, the areal capacity can reach 12.8 mAh cm−2. This work provides a guiding methodology for the design of catalytic materials and refinement of adsorption‐catalysis strategies for the rational design of cathode in lithium–sulfur batteries.
Primary hepatic carcinoma (PHC) is a common malignant tumor in China. Cancer is comprehensively treated with various therapeutic regimes, including traditional Chinese medicine (TCM). TCM has been widely used to improve the quality of life, delay the time of cancer progression, and prolong the median survival time. This systematic review with meta-analysis aimed to assess the effect of TCM combined with Western therapy on primary hepatic carcinoma. A comprehensive literature search was conducted in six databases, including CNKI, VIP, Wan-Fang Database, CBM, PubMed, and Cochrane library. A total of 44 randomized controlled trials (RCTs) involving 3429 participants suffering from PHC were selected. Meta-analysis results indicated that the overall effect of TCM and Western integrative treatment on PHC was higher than that of Western intervention alone, which can postpone tumor recurrence and metastasis and prolong the overall survival time of patients with PHC. Although the obtained evidence remained weak because of the poor methodological quality of the included studies, this review provided relevant data supporting the efficacy and safety of TCM combined with Western therapies. In future research, individual RCT studies should incorporate accepted standards for trial design and reporting, proper outcome indicators according to international standards, blinding in allocation concealment, and valid follow-up periods.
Nitrides could create opportunities of tuning resistive-switching (RS) characteristics due to their different electrical properties and ionic chemistry with oxides. Here, we reported on the effect of nitrogen-accommodation ability of electrodes in SiNx-based RS devices. The Ti/SiNx/Pt devices show a self-compliance bipolar RS with excellent reliability. The W/SiNx/Pt devices provide an unstable RS and fall to an intermediate resistance state (IRS) after a set process. The low resistance states of the Ti/SiNx/Pt devices obey Ohmic conduction and Frenkel-Poole emission from a conductive channel. The IRS of the W/SiNx/Pt devices conforms to Schottky emission and Fowler-Nordheim tunneling from a conductive channel/insulator/electrode structure. A nitrogen-ion-based model is proposed to explain the experimental results. According to the model, the nitrogen-accommodation ability of the electrodes dominates the nitrogen-reservoir size and the nitrogen-ion migration at the metal/SiNx interface, modulating the RS characteristics of the SiNx memory devices.
Metal phosphides have exhibited great potential in constructing high efficient sulfur cathode benefiting from their high conductivity, catalytic property, etc, which have been utilized to improve sulfur utilization, inhibit the...
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