We demonstrate the new features of a polyurethane shape memory polymer: water-driven actuation and recovery in sequence (i.e., programmable). Hydrogen bonding is identified as the reason behind these features. In addition, the absorbed water is quantitatively separated into two parts, namely, the free water and bound water. Their individual contribution on the glass transition temperature is identified.

Rational design of non-noble metal catalysts with the electrocatalytic activity comparable or even superior to Pt is extremely important for the future fuel cell-based renewable energy device. Herein, we demonstrate a new concept that metal-organic framework (MOF) can be used as a novel precursor to insitu encapsulate Co@Co 3 O 4 @C core@bishell nanoparticles (NPs) into a highly ordered porous carbon 10 matrix (CM) (denoted as Co@Co 3 O 4 @C-CM). The central cobalt ions from MOF are used as metal source to produce Co metal cores, which are later transformed into fancy Co@Co 3 O 4 nanostructure via a controlled oxidation. The most notable feature of our Co@Co 3 O 4 @C-CM is that the highly ordered CM can provide much better transport pathway than the disordered pure MOF derived nanostructure that can facilitate the mass transport of O 2 and electrolyte. As a result, the well-designed Co@Co 3 O 4 @C-CM 15 derived from MOF shows almost identical activity but superior stability and methanol tolerance for ORR relatively to the commercial Pt/C in alkaline medium. Our work first reports the novel Co@Co 3 O 4 @C nanostructure from MOF and also reveals the important role of the introduction of highly ordered carbon matrix into MOF derived catalyst on enhancing the ORR activity and stability. To the best of our knowledge, Co@Co 3 O 4 @C-CM is the most efficient non-noble metal nanocatalyst ever reported for 20 ORR. 65 (denoted as Co@Co 3 O 4 @C-CM), which is very different from the preparation of traditional nanocatalysts directly derived from MOFs. The central cobalt ions from MOFs were used as metal source to produce Co metal cores, which were later transformed into Co@Co 3 O 4 NPs via a simple oxidation process. Co 3 O 4 has 70

Well-defined porous carbon polyhedrons are synthesized directly from MOF nanocrystals and show high oxygen reduction reaction (ORR) catalytic activity in acid media.