Palladium has been recognized as the best anodic, monometallic electrocatalyst for the formic acid oxidation (FAO) reaction in a direct formic acid fuel cell. Here we report a systematic study of FAO on a variety of Pd nanocrystals, including cubes, right bipyramids, octahedra, tetrahedra, decahedra, and icosahedra. These nanocrystals were synthesized with approximately the same size, but different types of facets and twin defects on their surfaces. Our measurements indicate that the Pd nanocrystals enclosed by {1 0 0} facets have higher specific activities than those enclosed by {1 1 1} facets, in agreement with prior observations for Pd single‐crystal substrates. If comparing nanocrystals predominantly enclosed by a specific type of facet, {1 0 0} or {1 1 1}, those with twin defects displayed greatly enhanced FAO activities compared to their single‐crystal counterparts. To rationalize these experimental results, we performed periodic, self‐consistent DFT calculations on model single‐crystal substrates of Pd, representing the active sites present in the nanocrystals used in the experiments. The calculation results suggest that the enhancement of FAO activity on defect regions, represented by Pd(2 1 1) sites, compared to the activity of both Pd(1 0 0) and Pd(1 1 1) surfaces, could be attributed to an increased flux through the HCOO‐mediated pathway rather than the COOH‐mediated pathway on Pd(2 1 1). Since COOH has been identified as a precursor to CO, a site‐poisoning species, a lower coverage of CO at the defect regions will lead to a higher activity for the corresponding nanocrystal catalysts, containing those defect regions.

CdS-reduced graphene oxide (RGO) composites are successfully synthesized via the microwave-assisted reduction of graphite oxide in a CdS precursor solution using a microwave synthesis system. The photocatalytic performances of CdS-RGO composites in the reduction of Cr(VI) are investigated. The results show that CdS-RGO composites exhibit enhanced photocatalytic performance for the reduction of Cr(VI) with a maximum removal rate of 92% under visible light irradiation as compared with pure CdS (79%) due to the increased light absorption intensity and the reduction of electron-hole pair recombination in CdS with the introduction of RGO.

Because of the rapid development of flexible electronics, it is important to develop high-performance flexible energy-storage devices, such as supercapacitors and metal-ion batteries. Compared with metal-ion batteries, supercapacitors exhibit higher power density, longer cycling life, and excellent safety, and they can be easily fabricated into all-solid-state devices by using polymer gel electrolytes. All-solid-state supercapacitors (ASSSCs) have the advantages of being lightweight and flexible, thus showing great potential to be used as power sources for flexible portable electronics. Because of their high specific surface area and excellent electrical and mechanical properties, nanocarbon materials (such as carbon nanotubes, graphene, carbon nanofibers, and so on) have been widely used as efficient electrode materials for flexible ASSSCs, and great achievements have been obtained. Here, the recent advances in flexible ASSSCs are summarized, from design strategies to fabrication techniques for nanocarbon electrodes and devices. Current challenges and future perspectives are also discussed.

Due to inherently poor healable and stretchable features, the most explored polyvinyl alcohol-based gel electrolytes cannot well meet the requirements of stretchable, healable and multifunctional supercapacitors. Here, we report a hydrogel of a copolymer cross-linked by double linkers of Laponite (synthetic hectorite-type clay) and graphene oxide. The resultant hydrogel shows high mechanical stretchability, excellent ionic conductivity, and superior healable performance. Along with designing wrinkled-structure electrodes, supercapacitors fabricated by using this hydrogel as a gel electrolyte not only exhibit ultrahigh mechanical stretchability of 1000%, but also achieve repeated healable performance under treatments of both infrared light irradiation and heating. More significantly, a broken/healed supercapacitor also possesses an ultrahigh stretchability up to 900% with slight performance decay. This hydrogel electrolyte could be easily functionalized by introducing other functional components, and extended for use in other portable and wearable energy related devices with multifunction.

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Nitric oxide (NO) induces a multitude of antitumor activities, encompassing the induction of apoptosis, sensitization to chemo-, radio-, or immune-therapy, and inhibition of metastasis, drug resistance, angiogenesis, and hypoxia, thus attracting much attention in the area of cancer intervention. To improve the precise targeting and treatment efficacy of NO, a glutathione (GSH)-sensitive NO donor (1,5-bis­[(l-proline-1-yl)­diazen-1-ium-1,2-diol-O 2-yl]-2,4-dinitrobenzene, BPDB) coordinates with iron ions to form the nanoscale coordination polymer (NCP) via a simple precipitation and then partial ion exchange process. The obtained Fe­(II)-BNCP shows desirable solubility, biocompatibility, and circulation stability. Quick NO release triggered by high concentrations of GSH in tumor cells improves the specificity of NO release in situ, thus avoiding side effects in other tissues. Meanwhile, under high concentrations of H2O2 in tumors, Fe2+ ions in BPDB-based NCP, named Fe­(II)-BNCP, exert Fenton activity to generate hydroxyl radicals (·OH), which is the main contribution for chemodynamic therapy (CDT). In addition, ·O2 – generated by the Haber-Weiss reaction of Fe2+ ions with H2O2 can quickly react with NO to produce peroxynitrite anion (ONOO–) that is more cytotoxic than ·O2 – or NO only. This synergistic NO-CDT effect has been proved to retard the tumor growth in Heps xenograft ICR mouse models. This work not only implements a synergistic effect of NO-CDT therapy but also offers a simple and efficient strategy to construct a coordination polymer nanomedicine via rationally designed prodrug molecules such as NO donors.

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Stretchable supercapacitors that can sustain their performance under unpredictable tensile force are important elements for practical applications of various portable and wearable electronics. However, the stretchability of most reported supercapacitors was often lower than 100 % because of the limitation of the electrodes used. Herein we developed all-solid-state supercapacitors with a stretchability as high as 240 % by using aligned carbon nanotube composites with compact structure as electrodes. By combined with pseudocapacitive molybdenum disulfide nanosheets, the newly developed supercapacitor showed a specific capacitance of 13.16 F cm(-3) , and also showed excellent cycling retention (98 %) after 10 000 charge-discharge cycles. This work also presents a general and effective approach in developing high-performance electrodes for flexible and stretchable electronics.