Latest ArticlesDue to the involvement of four-electron transfer process at photoanode, water oxidation is the rate-limiting step in water splitting reaction. To settle this dilemma, ZnCo2O4 nanoparticles are combined with BiVO4 to form a p-n ZnCo2O4/BiVO4 heterojunction photoanode, which is proved by an input voltage−output current test. The built-in electric field formed within the heterojunction structure promotes the effective separation of electrons and holes. ZnCo2O4 is also an effective water oxidation cocatalyst, since it could cause the holes entering the electrode/electrolyte interface rapidly for the subsequent water oxidation reaction. The photocurrent density of ZnCo2O4/BiVO4 composite photoanode reaches 3.0 mA/cm2 at 1.23 V vs. RHE in 0.5 mol/L sodium sulfate under AM 1.5G simulated sunlight, about 2.1 times greater than that of BiVO4 (1.4 mA/cm2). These results suggest the potential of ZnCo2O4 nanoparticles for improving photoelectrochemical water splitting anode materials.
Supported NiCu bimetallic catalysts have been produced in-situ on commercial Al2O3 by using layered double hydroxides as precursors. The resulting catalysts show a uniform Ni and Cu distribution, thus providing good activity and selectivity in the reforming reaction of n-heptane. The catalytic performance has been found to depend on the Cu/Ni ratio, revealing the synergic catalysis between homogeneously dispersed Ni and Cu sites. The good catalysis of NiCu bimetallic catalysts makes it possible to partly or even completely replace Pt with NiCu bimetallic catalysts.
Triphenylamine (TPA) derivatives have been widely used as useful building blocks for diverse functional materials because of their excellent redox activity. Most of the molecular structures of TPA-based organic functional materials contain 4-anisyl groups, which on one hand could reduce their oxidation potential and on the other hand significantly delocalize the spin density of the resultant TPA radical cation species and enhance their stability. However, molecular-level investigation of the redox behavior of triphenylamines consisting of 4-anisyl group and the electronic structures of their radical cation species has not been reported in the literature. Herein, we design a series of triphenylamines consisting of one, two, or three 3, 5-di-tert-butyl-4-anisyl groups and investigate their redox behaviors and corresponding radical cation species. We disclose that the resonance hybrid and steric protection could both contribute to the stability of triphenylamine radical cations. Moreover, further oxidation leads to an unexpected oxidative demethylation. The findings in this work may reveal new insights for the understanding of the unique redox properties of 4-anisyl substituted triphenylamines.
In order to fully replace the traditional fossil energy supply system, the efficiency of electrochemical energy conversion and storage of new energy technology needs to be continuously improved to enhance its market competitiveness. The structural design of energy devices can achieve satisfactory energy conversion and storage performance. To achieve lightweight design, improve mechanical support, enhance electrochemical performance, and adapt to the special shape of the device, the structural energy devices develop very quickly. To help researchers analyze the development and get clear on developing trend, this review is prepared. This review summarizes the latest developments in structural energy devices, including special attention to fuel cells, lithium-ion batteries, lithium metal batteries, and supercapacitors. Finally, the existing problems of structural energy devices are discussed, and the current challenges and future opportunities are summarized and prospected. Structural energy devices can undoubtedly overcome the performance bottlenecks of traditional energy devices, break the limitations of existing materials and structures, and provide a guidance for the development of equipment with high performance, light weight and low cost in the future.
A high incidence of bone defects and the limitation of autologous bone grafting require 3D scaffolds for bone repair. Compared with synthetic materials, natural edible materials possess outstanding advantages in terms of biocompatibility, bioactivities and low manufacturing cost for bone tissue engineering. In this work, attracted by the natural porous/fabric structure, good biocompatibility and bioactivities of the lotus root, the lotus root-based scaffolds were fabricated and investigated their potential to serve as natural porous bone tissue engineering scaffolds. The results indicated that the lotus root-based scaffolds possess suitable natural microstructure, excellent biocompatibility and promising functions, such as antioxidant capacity and angiogenesis promotion. Remarkably, lotus root scaffolds showed encouraging possibility of bone tissue engineering while the mineralized lotus root could further improve the bone regeneration in vivo. All the results demonstrated the bone regeneration potential of lotus root-based scaffolds equipped with suitable natural architecture, excellent biocompatibility, specific bioactivities and low manufacturing cost.
Theranostic visualization of dextran at the nanoscale is beneficial for understanding the bioregulatory mechanisms of this molecule. In this study, we applied structured illumination microscopy (SIM) to capture the distribution of Cy5-Dextran at different incubation periods in living cells. The results showed that Cy5-Dextran could be absorbed by HeLa cells. In addition, we clarified that Cy5-Dextran exhibited differential organelle distribution (lysosomal or mitochondrial) in a time-dependent manner. Moreover, lysosomal Cy5-Dextran localization was found to be independent of the autophagy process, while Cy5-Dextran localized to the mitochondria triggered a pro-apoptotic event, upregulating the levels of reactive oxygen species (ROS) to accelerate mitochondrial fragmentation. This work uses a visualized strategy to reveal the anti-tumor bioactivity of dextran, which was achieved by regulating apoptosis and autophagy.
A novel method for metal-free C-H borylation of 2-(N-methylanilino)-5-fluoropyridines and 2-benzyl-5-fluoropyridines has been reported. The 5-fluoropyridine directed borylation reaction exhibited high efficiency and site exclusivity. The useful protocol could be executed on a gram-scale easily and the borylated products showed good derivatization applications. Moreover, the practicality of the strategy was expanded by the fact that the directing group could be removed in an acceptable yield.
Advances in microbiology rely on innovations in technology. Droplet microfluidics, as a versatile and powerful technique that allows high-throughput generation and manipulation of subnanoliter volume droplets, has become an indispensable tool shifting experimental paradigms in microbiology. Droplet microfluidics has opened new avenues to various microbiological research, from resolving single-cell heterogeneity to investigating spatiotemporal dynamics of microbial communities, from precise quantitation of microbiota to systematic decipherment of microbial interactions, and from isolating rare and uncultured microbes to improving genetic engineered strains. In this review, we present recent advances of droplet microfluidics in various fields of microbiology: i) microbial cultivation, ii) microorganism detection and characterization, iii) antibiotic susceptibility testing, iv) microbial interactions, v) microbial biotechnology. We also provide our perspectives on the challenges and future directions for droplet microfluidic-based microbiology research.
Herein, an efficient molecular oxygen-mediated method for the selective hydroxyalkylation and alkylation of quinoxalin-2(1H)-ones with alkylboronic acids under transition-metal free conditions has been developed. This strategy demonstrates a broad scope of quinoxalin-2(1H)-ones and alkylboronic acids, giving 3-hydroxyalkylquinoxalin-2(1H)-ones and 3-alkylquinoxalin-2(1H)-ones in moderate-to-good yield. Control experiments reveal that a radical pathway is involved.
Noble metal aerogels (NMAs), belonging to the porous material, have exhibited excellent catalytic performance. Although the synthesis method continues to improve, it still exists some problems which hindered the experimental process, such as high concentration of noble metal precursors, long synthesis cycle, expensive production cost, and uncontrollable ligament length. In this work, ultrasonic wave and reducing agent NaBH4 were simultaneously applied to gelation process. With the cavitation of ultrasound, it can generate huge energy with heating and stirring, thus gelation reaction proceeded quickly, and even completed the process in only a few seconds, that is much faster than the recorded. A wide concentration range was successfully expanded from 0.02 mmol/L to 62.5 mmol/L. Further, we extended this method to a variety of noble metal elements (Au, Ru, Rh, Ag, Pt, Pd), and this method is adaptive for the synthesis of single metal aerogels (Au, Ag, Ru, Rh, Pd), bimetal and trimetal aerogels (Au-Ag, Au-Rh, Au-Ru, Au-Pt, Au-Pd, Au-Pt-Pd). In addition, the ligament size of alloy aerogels are 10 nm or less. Moreover, their brilliant properties were demonstrated in hydrogen evolution reaction (HER) and ethanol oxidation reaction (EOR).