A bifunctional MOF@POP core-shell catalyst (NH 2 -UiO-66(Hf)@CoTPy-CAP) constructed by amino functionalized NH 2 -UiO-66(Hf) and ionic porphyrin-based CoTPy-CAP was first reported to be applied in the cycloaddition of CO 2 . Because NH 2 -UiO-66(Hf)@CoTPy-CAP both possess abundant Lewis acidic sites and nucleophilic centers in one system, the catalyst can efficiently catalyze CO 2 fixation with epoxides without homogeneous cocalyst under mild conditions, achieving propylene oxide (PO) conversion of 98 % at 80 °C and 0.5 MPa. Furthermore, the bifunctional synergetic catalyst was easy to be recovered and recycled for five runs, and the reduction of activity was not obvious. This present work provides a viable direction for the fabrication of bifunctional synergetic catalysts for high-efficient CO 2 fixation without cocatalyst under mild conditions.
Stimuli-responsive color-changing and shape-changing hydrogels are promising intelligent materials for visual detections and bio-inspired actuations, respectively. However, it is still an early stage to integrate the color-changing performance and shape-changing performance together to provide bi-functional synergistic biomimetic devices, which are difficult to design but will greatly expand further applications of intelligent hydrogels. Herein, we present an anisotropic bi-layer hydrogel by combining a pH-responsive rhodamine-B (RhB)-functionalized fluorescent hydrogel layer and a photothermal-responsive shape-changing melanin-added poly (N-isopropylacrylamide) (PNIPAM) hydrogel layer with fluorescent color-changing and shape-changing bi-functional synergy. This bi-layer hydrogel can obtain fast and complex actuations under irradiation with 808 nm near-infrared (NIR) light due to both the melanin-composited PNIPAM hydrogel with high efficiency of photothermal conversion and the anisotropic structure of this bi-hydrogel. Furthermore, the RhB-functionalized fluorescent hydrogel layer can provide rapid pH-responsive fluorescent color change, which can be integrated with NIR-responsive shape change to achieve bi-functional synergy. As a result, this bi-layer hydrogel can be designed using various biomimetic devices, which can show the actuating process in the dark for real-time tracking and even mimetic starfish to synchronously change both the color and shape. This work provides a new bi-layer hydrogel biomimetic actuator with color-changing and shape-changing bi-functional synergy, which will inspire new strategies for other intelligent composite materials and high-level biomimetic devices.
危险品化学品经营许可证（带存储）