Developing photocatalysts capable of visible-lightdriven water splitting to produce clean hydrogen (H 2 ) is one of the premier challenges for solar energy conversion into clean and sustainable fuels. Inspired from the structure feature of photosystem I in nature, we have designed and synthesized a series of robust covalent organic frameworks (NKCOFs = Nankai University COFs) based on electric donor−acceptor moieties, in which the electron-donor group of pyrene can be used for harvesting light. Meanwhile, benzothiadiazole with different functional groups was introduced as an electron acceptor to tune the light-adsorption ability of COFs. Notably, the activity of NKCOF-108 for photochemical H 2 evolution under visible light was among the highest in COFs without hybridization with other materials. We attribute the high hydrogen evolution rate of NKCOF-108 to its distinct structural features and wide visible-lightresponse range. The highly ordered layered structure ensures that sufficient active sites are accessible for H 2 production, and the donor−acceptor design can promote the separation of photogenerated carriers. Our findings have provided an effective strategy to design photocatalysts for light-driven H 2 evolution.

Pt-based alloy catalysts may promise considerable mass activity (MA) for oxygen reduction but are generally unsustainable over long-term cycles, particularly in practical proton exchange membrane fuel cells (PEMFCs). Herein, we report a series of Pt-based intermetallic compounds (Pt3Co, PtCo, and Pt3Ti) enclosed by ultrathin Pt skin with an average particle size down to about 2.3 nm, which deliver outstanding cyclic MA and durability for oxygen reduction. By breaking size limitation during ordered atomic transformation in Pt alloy systems, the MA and durability of subsize Pt-based intermetallic compounds can be simultaneously optimized. The subsize scale was also found to enhance the stability of the membrane electrode through preventing the poisoning of catalysts by ionomers in humid fuel-cell conditions. We anticipate that subsize Pt-based intermetallic compounds set a good example for the rational design of high-performance oxygen reduction electrocatalysts for PEMFCs. Furthermore, the prevention of ionomer poisoning was identified as the critical parameter for assembling robust commercial membrane electrodes in PEMFCs.

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The objective of the study was to systematically investigate flavor compounds in Chinese rice wine (CRW) using chromatography technology. In twelve CRW samples, 93 different flavor compounds were detected and identified including 16 alcohols in addition to ethanol, 29 esters, 9 aldehydes, 9 organic acids, 19 amino acids and 11 fatty acids. Statistical analysis by principal component analysis (PCA) indicated that seventeen flavor compounds in Guyue Longshan rice wine made a large contribution to its special flavor. These compounds were benzaldehyde, acetaldehyde, ethyl 2-hydroxy-4-methylvalerate, ethyl butyrate, phenyl ethyl isobutyrate, ethyl benzoate, ethyl phenylacetate, methyl dodecanoate, methyl oleate, ethyl dedecanoate, 1-butanol, 3-ethoxyl-1-propanol, 1-enanthol, dodecanol, lactic acid, fumaric acid and lauric acid.