Nanoparticles are among the most important industrial catalysts, with applications ranging from chemical manufacturing to energy conversion and storage. Heterogeneity is a general feature among these nanoparticles, with their individual differences in size, shape, and surface sites leading to variable, particle-specific catalytic activity. Assessing the activity of individual nanoparticles, preferably with subparticle resolution, is thus desired and vital to the development of efficient catalysts. It is challenging to measure the activity of single-nanoparticle catalysts, however. Several experimental approaches have been developed to monitor catalysis on single nanoparticles, including electrochemical methods, single-molecule fluorescence microscopy, surface plasmon resonance spectroscopy, X-ray microscopy, and surface-enhanced Raman spectroscopy. This review focuses on these experimental approaches, the associated methods and strategies, and selected applications in studying single-nanoparticle catalysis with chemical selectivity, sensitivity, or subparticle spatial resolution.
The most significant factors influencing beer quality are the variety of aroma flavours that stem from a complex system of interactions between many hundreds of compounds. With increasing demand for flavour control and enhanced productivity, the presence of consistent and balanced amounts of higher alcohols and esters are critical aspects of process control. Extensive research has focused on the formation of flavour compounds by the brewing yeast and the factors that influence their synthesis. Fermenting wort is a complex medium from which the brewing yeast utilizes nutrients for living and growth and to where it places its metabolic by-products. Thus, changes in wort composition will greatly influence final beer aroma. The current paper reviews up-to-date knowledge on the contribution of wort composition to the flavour quality of the final product, in particular higher alcohols and esters. Different wort constituents involved in the biosynthesis of these aromatic substances, and which therefore require control during brewery fermentations, are reviewed.
CdS nanowires decorated with ultrathin MoS2 nanosheets were synthesized for the first time by ultrasonic exfoliation by using dimethylformamide as the dispersing agent. An excellent hydrogen evolution rate of 1914 μmol h(-1) (20 mg catalyst) under visible-light irradiation (λ ≥ 400 nm, ≈ 154 mW cm(-1) ) and an apparent quantum yield of 46.9% at λ=420 nm were achieved over the MoS2 /CdS composite. The presence of ultrathin MoS2 nanosheets (rich in active edge sites) on the CdS surface promotes the separation of photogenerated charge carriers and facilitates the surface processes of photocatalytic hydrogen evolution.
Solar cells and rechargeable batteries are two key technologies for energy conversion and storage in modern society. Here, an integrated solar‐driven rechargeable lithium–sulfur battery system using a joint carbon electrode in one structure unit is proposed. Specifically, three perovskite solar cells are assembled serially in a single substrate to photocharge a high energy lithium–sulfur (Li–S) battery, accompanied by direct conversion of the solar energy to chemical energy. In the subsequent discharge process, the chemical energy stored in the Li–S battery is further converted to electrical energy. Therefore, the newly designed battery is capable of achieving solar‐to‐chemical energy conversion under solar‐driven conditions, and subsequently delivering electrical energy from the stored chemical energy. With an optimized structure design, a high overall energy conversion efficiency of 5.14% is realized for the integrated battery. Moreover, owing to the self‐adjusting photocharge advantage, the battery system can retain high specific capacity up to 762.4 mAh g
−1
under a high photocharge rate within 30 min, showing an effective photocharging feature.
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