The direct formic acid fuel cell (DFAFC), with its high energy conversion efficiency, high energy density, rapid startup at room temperature, and other excellent features, is considered one of the most promising sources of green energy. Here, corallike PdCu bimetallic nanoparticles with large surface areas were successfully designed and fabricated via a simple approach and were used as an efficient electrocatalyst for formic acid oxidation (FAO). Introduction of Cu atoms into coral-like PdCu bimetallic nanoparticles not only affects the d-band centers of active sites by enhancing the catalytic performance but can also adjust the morphology to provide increased specific surface area. In addition, the electrocatalytic activity of the obtained PdCu/C was well optimized in FAO by tuning the composition of the metallic elements and the ratio of catalyst supports. The optimal electrocatalyst has an electrochemically active area of 36.34 m 2 g −1 and a mass activity of 1.05 A g Pd −1 , which are approximately 2 and 3.5 times higher than the values from commercial Pd/C, respectively. Most importantly, the chronoamperometry curve remained above 60% after 400 s, which is dramatically increased compared with Pd/C (<2.5%), illustrating the high stability of the PdCu bimetallic nanoparticle catalyst.

Methanol is extremely harmful to human health, since it is oxidized slowly and can accumulate in the human body. Therefore, it is essential to develop a methanol gas sensing technology with high sensitivity and selectivity for use in environmental monitoring and healthcare. In this work, a simple and low‐cost sensor based on a Y2O3 multishelled hollow structure (YMSH) to selectively detect methanol with an ultrasensitive limit of detection (71 ppb) is developed. The unique multishelled hollow structure with a large surface area and exposed {222} facets makes an important contribution to the ultrasensitive detection of methanol, which is further confirmed by subsequent theoretical simulations. Moreover, in situ Fourier transform infrared spectra verify that CO2 is the final product, which indicates a high catalytic activity of the YMSHs toward methanol oxidation. Interestingly, the sensor can also be applied to liquor samples that are mixtures of ethanol, methanol, and water, which provides a facile way to detect methanol in wines. This sensor represents a unique and highly sensitive means to detect methanol, which has great promise for potential application in environmental monitoring and food safety inspection.

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The design and synthesis of three kinds of arylamide molecules (compounds 1～3) containing halogen bonding donor and acceptor fragments, and the exploration and analyzation of different action modes of halogen bonding in solid phase were reported. Compounds 1 and 2 contain two tetrafluoroiodobenzene fragments, and compound 1 also contains a halogen receptor fragment-pyridine group. Isobutyl groups are introduced into the molecule to increase its solubility and crystallinity. And a pyrimidine fragment was introduced into compound 3, which has more aromatic rings. The two N atoms of the pyrimidine fragment can theoretically form intramolecular hydrogen bonds with the adjacent amide hydrogen atoms (-C(＝O)NH), so that the whole molecule has the properties of hydrogen-bonded arylamide foldamer. Moreover, trifluorobenzene fragments were selected in compound 3 to eliminate the repulsion between excess fluorine atoms and carbonyls. The crystal structures reveal that the three aromatic rings in compound 1 are twisted with each other for there is no intramolecular hydrogen bond, and a supramolecular DNA-like double helix was assembled controlled by intermolecular N…I and O…I halogen bonds arranged alternately. Compound 2 failed to form an intramolecular three-center hydrogen bonding due to the repulsion between the amide carbonyl groups and the two fluorine atoms in close proximity. As expected, in the solid phase of compound 3, an effective three-center hydrogen bond is formed between the terminal trifluoroiodobenzene and the benzene ring attached to it. Moreover, the two N-H bonds connected to the pyrimidine ring also form two effective three-center hydrogen bonds. The difference is that the participants of these two groups of three-center hydrogen bonds include two N atoms in the pyrimidine ring. The four aromatic rings in compound 3 are nearly coplanar driven by these intramolecular three-center hydrogen bonds. Two sets of strong intermolecular (pyridine ring) N…I halogen bonds control the formation of [1＋1] bimolecular supramolecular macrocycles with inner diameters of 1.36 nm and 1.07 nm in length and width. Moreover, the supramolecular macrocycle is near-planar due to the introduction of pyrimidine ring.