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排序方式: 共有3804条查询结果,搜索用时 31 毫秒
31.
An in-depth mechanistic insight into the redox reaction and degradation of aqueous Zn-MnO2 batteries
《中国化学快报》2023,34(4):107525
Rechargeable aqueous Zn/MnO2 batteries raise massive research activities in recent years. However, both the working principle and the degradation mechanism of this battery chemistry are still under debate. Herein, we provide an in-depth electrochemical and structural investigation on this controversial issue based on α-MnO2 crystalline nanowires. Mechanistic analysis substantiates a two-electron reaction pathway of Mn2+/Mn4+ redox couple from part of MnO2 accompanying with a reversible precipitation/dissolution of flaky zinc sulfate hydroxide (ZSH) during the discharge/charge processes. The formation of the ZSH layer is double-edged, which passivates the deep dissolution of MnO2 upon discharging, but promotes the electrochemical deposition kinetics of active MnO2 upon charging. The cell degradation originates primarily from the corrosion failure of metallic zinc anode and the accumulation of irreversible ZnMn2O4 phases on the cathode. The addition of MnSO4 to the electrolyte could afford supplementary capacity contribution via electro-oxidation of Mn2+. However, a high MnSO4 concentration will expedite the cell failure by corroding the metallic zinc anodes. The present study will shed a fundamental insight on developing new strategies toward practically viable Zn/MnO2 batteries. 相似文献
32.
《中国化学快报》2023,34(7):107767
Compared with solid alkali metal anodes (Li, Na, K), liquid metal anodes (LMAs) could enable high-energy batteries due to their unique advantages, such as self-healing property and no dendrites. Among LMAs, liquid Na-K alloy anode has become a hotspot due to its high theoretical capacity, low redox potential and formation at room temperature (RT). However, it is challenging to utilize liquid Na-K alloy directly and independently as an electrode; and the high surface tension makes it more difficult to immerse into porous current collectors at RT. Herein, an amorphous hollow carbon film (AHCF) consisting of hollow spheres with significant surface defects has been designed to quickly infiltrate Na-K liquid alloy into the hollow carbon film at RT, forming a composite electrode (Na-K@AHCF). The symmetric cell with Na-K@AHCF could exhibit a cycle lifespan up to 400 h at 0.1 mA/cm2 and achieve stable stripping/deposition even at 5 mA/cm2. When matching with cathode material of sulfurized polyacrylonitrile (SPAN), the obtained K-S full cell exhibits good cycle stability and rate performance. 相似文献
33.
《中国化学快报》2023,34(7):107787
Metal-organic frameworks (MOFs) as promising electrodes for supercapacitors are attracting increasing research interest. Herein, we report an effective strategy to improve the electrochemical performance of Ni-MOF for supercapacitor by introducing a secondary Co ion. The Co substitution of Ni in Ni-MOF can improve the intrinsic reactivity and stability. As a result, the bimetallic Co/Ni-MOF-1:15 with an optimal Co/Ni ratio delivers high specific capacitance (359 F/g at 0.5 A/g), good rate performance (81.5% retention at 5 A/g) and cycling stability (81% retention after 5000 cycles). These results demonstrate that the bimetallic synergistic strategy is an effective way to improve the pseudocapacitive performance of MOFs. 相似文献
34.
《中国化学快报》2023,34(7):107815
Mesoporous carbon supported with transition metals nanoparticles performs desired activities for oxygen reduction reaction (ORR) and clean energy conversion devices such as Zn–air batteries. In this work, we synthesized N-doped mesoporous carbon loaded with cobalt nanoparticles (CoMCN) through self-assembly method. There are sufficient mesopores on the carbon substrate which stem from the pore-forming agent. These mesopores can provide enough accessible active sites and profitable charge/mass transport for ORR. The high content of pyridinic and graphitic N is beneficial for promoting O2 adsorption and reduction. The smaller value of ID/IG indicates the higher degree of graphitization of CoMCN, providing better electronic conductivity. The half-wave potential of CoMCN is 0.865 V in basic solution, which is 24 mV more positive than that of the commercial Pt/C (0.841 V). In addition, CoMCN performs excellent methanol tolerance and stability under both basic and acidic conditions. The Zn–air battery assembled with CoMCN performs the larger power density and open-circuit voltage than the commercial Pt/C-based battery, indicating the potential application in energy conversion systems. This work provides thoughtful ideas for fabricating transition metal nanoparticles based porous carbon for electrocatalysis and metal–air batteries. 相似文献
35.
《中国化学快报》2023,34(8):108074
Shortcut nitrification-denitrification (SCND) is widely concerned because of its low energy consumption and high nitrogen removal efficiency. However, the current difficulty lies in the stable maintenance of SCND performance, which leads to the challenge of large-scale application of this new denitrification technology. In this study, the nitrogen removal pathway from complete nitrification-denitrification (CND) to SCND was rapidly realized under high free ammonia (FA), high pH and low dissolved oxygen (DO) conditions. The variations of specific oxygen uptake rate (SOUR) of activated sludge in both processes were investigated by an online SOUR monitoring device. Different curves of SOUR from CND to SCND process were observed, and the ammonia peak obtained based on SOUR monitoring could be used to control aeration time accurately in SCND process. Accordingly, the SOUR ratio of ammonia oxidizing bacteria (AOB) to nitrite oxidizing bacteria (NOB) (SOURAOB/SOURNOB) was increased from 1.40 to 2.93. 16S rRNA Miseq high throughput sequencing revealed the dynamics of AOB and NOB, and the ratio of relative abundance (AOB/NOB) was increased from 1.03 to 3.12. Besides, SOURAOB/SOURNOB displayed significant correlations to ammonia removal rate (P<0.05), ammonia oxidation rate / nitrite oxidation rate (P < 0.05), nitrite accumulation rate (P < 0.05) and the relative abundance of AOB/NOB (P < 0.05). Thus, a strategy for evaluation the SCND process stability based on online SOUR monitoring is proposed, which provides a theoretical basis for optimizing the SCND performance. 相似文献
36.
Dr. Zhao Gao Lulu Shi Fei Yan Yifei Han Wei Yuan Prof. Wei Tian 《Angewandte Chemie (International ed. in English)》2023,62(21):e202302274
Two-dimensional (2D) organic polymers have recently received considerable interest, especially those whose architectures are held together via supramolecular engineering. However, current approaches toward supramolecular 2D structures usually suffer from mutual interference of noncovalent interactions and lack of intrinsic functions. Herein, we report well-regulated 2D supramolecular polymers (2DSPs) through an aromatics-selective recognition strategy of cation-π and donor-acceptor (D-A) motifs, which are derived from C4-symmetric cationic monomers and electron-withdrawing molecules. By subtly designing the strength and direction of noncovalent driving forces, the mutual interference between cation-π and D-A interactions is effectively avoided, enabling the construction of 2DSPs in aqueous solution. On this basis, the resultant 2DSPs possess boosted photocatalytic hydrogen evolution activity at a rate of 600 μmol g−1 h−1, which is mainly ascribed to the specific stacking mode of cation-π/D-A motifs and the ordered 2D structures. 相似文献
37.
Dr. Zixuan Xu Zhaoyu Wang Dr. Wei Yao Yanhua Gao Yuxin Li Dr. Huifang Shi Prof. Wei Huang Prof. Zhongfu An 《Angewandte Chemie (International ed. in English)》2023,62(24):e202301564
Dynamic room temperature phosphorescence (RTP) materials have potential applications in optoelectronics, which inevitably suffer from poor processability, flexibility or stretchability. Herein, we report a concise strategy to develop supercooled liquids (SCLs) with dynamic RTP behavior using terminal hydroxyl engineering. The terminal hydroxyls effectively hinder the nucleation process of molecules for the formation of stable SCLs after thermal annealing. Impressively, the SCLs show reversible RTP emission via alternant stimulation by UV light and heat. Photoactivated SCLs have phosphorescent efficiency of 8.50 % and a lifetime of 31.54 ms under ambient conditions. Regarding the dynamic RTP behavior and stretchability of SCLs, we demonstrate the applications in erasable data encryption and patterns on flexible substrates. This finding provides a design principle for obtaining SCLs with RTP and expands the potential applications of RTP materials in flexible optoelectronics. 相似文献
38.
Shengmei Chen Yiran Ying Shengnan Wang Longtao Ma Haitao Huang Xiaoqi Wang Xu Jin Shengchi Bai Prof. Chunyi Zhi 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301467
Though massive efforts have been devoted to exploring Br-based batteries, the highly soluble Br2/Br3− species causing rigorous “shuttle effect”, leads to severe self-discharge and low Coulombic efficiency. Conventionally, quaternary ammonium salts such as methyl ethyl morpholinium bromide (MEMBr) and tetrapropylammonium bromide (TPABr) are used to fix Br2 and Br3−, but they occupy the mass and volume of battery without capacity contribution. Here, we report an all-active solid interhalogen compound, IBr, as a cathode to address the above challenges, in which the oxidized Br0 is fixed by iodine (I), thoroughly eliminating cross-diffusing Br2/Br3− species during the whole charging and discharging process. The Zn||IBr battery delivers remarkably high energy density of 385.8 Wh kg−1, which is higher than those of I2, MEMBr3, and TPABr3 cathodes. Our work provides new approaches to achieve active solid interhalogen chemistry for high-energy electrochemical energy storage devices. 相似文献
39.
《印度化学会志》2023,100(6):100994
Drugs used in the management of Hepatitis B virus (HBV) infection are largely based on nucleosides or their analogues and these have several side-effects. These drugs only inhibit viral replication, cannot eliminate cccDNA and present with serious long-term effects. Hence, researchers are now searching for potential targets that present with less side-effect and are more effective. The study was aimed at evaluating and comparing the antiviral drug-like potential of troxerutin against various HBV proteins and entecavir. In this study, troxerutin was purified, synthesized and characterized using 1H NMR, 13C NMR and FT-IR. In addition, detailed investigation using density functional theory (DFT), and in-silico molecular docking of troxerutin and entecavir against various HBV proteins were conducted. The spectral analysis (NMR and FT-IR) confirmed the presence of characteristic functional groups with the presence of C–H, C–C and OH bonds/vibrations. Docking result showed excellent binding affinities across all four HBV proteins with the bindings scores for troxerutin (−6.3 to −7.1 kcal/mol) that was similar to those of entecavir (−6.2 to −7.8 kcal/mol). Unlike entecavir, troxerutin did not show any predicted hepatotoxicity but appears to be immunotoxic with an LD50 value of 1000 mg/kg. Given the anti-HBV potential of troxerutin this study has revealed, further in-vivo and in-vitro studies are needed to validate these findings. 相似文献
40.
《印度化学会志》2023,100(6):101014
In this study, renewable, non-toxic, sulphur free bio-lubricants are synthesized as alternative for fossil fuels. We utilized a bio-derived 10-undecylenic acid (UDA) and pentaerythritol (PE) as raw materials to synthesize bio-lubricants by two-step chemical processes like esterification and followed by epoxidation reactions. And achieved a UDA-PE epoxide yielded 73.4%. The formation of UDA-PE ester and UDA-PE epoxide was confirmed by spectral analysis such as NMR (1H and 13C), FTIR and mass spectra, Physico-chemical and basic lubricant properties by standard American Society for Testing and Materials methods (ASTM). The results showed that the products of UDA-PE ester and UDA-PE epoxide had high viscosity index (262 and 200), good pour points (−29 °C to −15 °C), high flash points (296 °C and 301 °C) respectively and these met the ISO VG (International Organization for Standardization-Viscosity grade) 22 and 220 standard values. In general, both synthesized products are plausible to be employed as bio-lubricant in industrial application. 相似文献