Selective hydrogenation of phenol to cyclohexanone over a catalyst of polyaniline‐functionalized carbon‐nanofiber‐supported palladium (Pd‐PANI/CNF) with sodium formate as the hydrogen source has been studied. Phenol conversion exceeding 99 % was achieved with a cyclohexanone selectivity of >99 % in aqueous media. In an extension to Pd‐PANI/CNF, polymers such as polypyrrole (PPY), poly(4‐vinylpyridine) (PVP), and poly(1‐vinylimidazole) (PVI) were further applied to a catalyst of Pd‐polymer/CNF for selective phenol hydrogenation. All of the Pd‐polymer/CNF catalysts showed excellent to good performance toward selective phenol hydrogenation. However, Pd‐PANI/CNF was considerably more active and selective to afford the desired cyclohexanone than Pd‐PPY/CNF, Pd‐PVP/CNF, and Pd‐PVI/CNF. Moreover, a series of phenol‐derived compounds were selectively hydrogenated in high yields under the investigated aqueous conditions. The research highlights an environmentally benign and effective process for the selective reduction of phenol derivatives with sodium formate as an alternative hydrogen source.

Miniaturization of functional devices and systems demands new design and fabrication approaches for lab-on-a-chip application and optical integrative systems. By using a direct laser writing (DLW) technique based on two-photon polymerization (TPP), a highly integrative optofluidic refractometer is fabricated and demonstrated based on tubular optical microcavities coupled with waveguides. Such tubular devices can support high quality factor (Q-factor) up to 3600 via fiber taper coupling. Microtubes with various diameters and wall thicknesses are constructed with optimized writing direction and conditions. Under a liquid-in-tube sensing configuration, a maximal sensitivity of 390 nm per refractive index unit (RIU) is achieved with subwavelength wall thickness (0.5 μm), which offers a detection limit of the devices in the order of 10 RIU. Such tubular microcavities with coupled waveguides underneath present excellent optofluidic sensing performance, which proves that TPP technology can integrate more functions or devices on a chip in one-step formation.