The achievement of highly active and stable piezocatalysts is still challenging for the efficient transformation of mechanical energy to chemical energy. Herein various SnOxHy species were prepared by a simple precipitation–thermal treatment method and applied for the piezocatalytic degradation of tricyclazole. It is found that the catalytic activity depended on the thermal treatment and follows the order SnO(OH)2 (80 °C) > SnO2.55H1.1 (200 °C) > SnO2.3H0.6 (300 °C) > SnO2.22H0.24 (400 °C) > SnO2 (500 °C) > rutile SnO2 (800 °C). SnO(OH)2 (80 °C) boosted the degradation of tricyclazole and the reaction constant reached as high as 0.0354 min−1, 7.1 fold that of SnO2 (800 °C). The differences among these SnOxOHy piezocatalysts mainly stemmed from the dissimilarity of the relative content of SnO(OH)2. In addition to the Sn–O piezoelectric motif, SnO(OH)2 had rich hydrogen bond networks, which work like molecular springs under external pressure. Due to such a special structure, SnO(OH)2 had not only a super high piezoelectric constant (d33) of 409.1 pm V−1 among the currently reported piezomaterials, but also a 0.49 eV-higher valence band than SnO2, being beneficial to the generation of stronger oxidative ˙OH. This is the first example of inorganic hydrogen-bonded piezomaterials, which opens a new window to develop advanced piezocatalysts for highly efficient degradation of refractory pollutants by piezocatalysis.
Reverse osmosis (RO) membranes have been widely used in water treatment systems and exhibit outstanding separation performance. However, due to the complex composition of industrial wastewater, insoluble inorganic scales (e.g., barium sulfate) are difficult to remove from the membrane surface, which severely impairs the membrane performance. Herein, pH-responsive “molecular springs” were grafted onto the fouled polyamide RO membrane by directly penetrating the inorganic scale layers. The “molecular springs” stretch and shrink with pH variations, enabling the removal of barium sulfate scales through simple alkali-acid cleaning. The content of barium scales on the membrane surface was found to significantly decrease from 45.74 % to 0.61 %, resulting in an increase of membrane flux from 60.99 L/(m 2 h) to 71.94 L/(m 2 h). For the full size membrane modules, this study has also demonstrated that the insoluble scales on the industrial RO membrane can be removed as effectively and easily as the soluble scales by grafting “molecular springs”.
Two-way shape memory polymers (2WSMP) are highly desired for artificial muscles, soft actuators and sensors, while the stress-free 2WSMP greatly expands the practical potential of shape memory polymers. However, traditional 2WSMP cannot show high strength or good mechanical properties, which limited its practical application. It is important to create a new reversible polymer system in order to obtain more intricate movements, precise control and great mechanical properties. Herein, a two-way shape memory polyurethane was created using a new molecular strategy, which shows great properties, i.e., 2342% super stretch strain, 591 MPa true tensile strength, 708.04 J/kg of energy density, and 667.96 W/kg of power density. In addition, the 2WSMP could achieve a maximum 24.53% reversible transformation under 1 MPa stress, and 13.7% two-way shape change without external stress, respectively. In this polyurethane, the great mechanical properties and stress-free two-way shape memory effect are caused by the elastic polybutadiene (PB) segments, which acts as a “molecular spring.” Furthermore, this 2WSMP could simulate reversible muscle-like motion, and be employed in ligaments. Consequently, this polyurethane offers a fresh design concept for stress-free two-way performance memory polymers and has a wide range of potential applications in the field of artificial muscles, soft actuators and ligaments.
危险品化学品经营许可证（带存储）