Polymeric ruthenium porphyrin-functionalized carbon nanotubes (Ru-PP/CNTs) were prepared by the metallation of polymeric porphyrin-functionalized carbon nanotubes (PP/CNTs) with Ru 3 (CO) 12 , whereas PP/CNTs were obtained by the condensation of terephthaldehyde and pyrrole in the presence of CNTs. The Ru-PP/CNTs have a thin layer of highly cross-linked polymeric ruthenium porphyrin coating over the CNT surface via strong π–π stacking interactions, thus showing a bilayered structure with an amorphous polymeric outer surface and an internal CNT core. Polymeric ruthenium porphyrin-functionalized reduced graphene oxide (Ru-PP/RGO) was prepared with a synthetic procedure similar to Ru-PP/CNTs, with RGO as the internal core. Both Ru-PP/CNTs and Ru-PP/RGO showed excellent catalytic performance toward hydrogenation of biomass-related ethyl levulinate (EL) to γ-valerolactone (GVL) with Ru-centered porphyrin units as the catalytic active species. Under optimized reaction conditions, a GVL yield higher than 99% with a complete conversion of EL was observed over both Ru-PP/CNTs and Ru-PP/RGO. In addition to GVL preparation, the versatile Ru-PP/CNTs can efficiently promote reductive amination of EL with various amines for the synthesis of pyrrolidone derivatives, with the corresponding yields ranging from 96.3 to 88.7%. Moreover, the composite materials of both Ru-PP/CNTs and Ru-PP/RGO behave as heterogeneous catalysts in the reaction system and can be easily reused.

Forming natural polymers‐based hydrogels with enhanced mechanical strength, outstanding antifreezing property and superior conductivity is still a challenge. Here, gelatin/oxidized dextran hydrogel is fabricated and it shows enhanced mechanical performance, antifreeze tolerance, and conductivity due to the synergistic interaction of ammonium sulfate and betaine. The resulting gelatin/oxidized dextran/(NH4)2SO4/betaine hydrogel exhibits high stretchability (570%), tough tensile (2.49 MPa) and compressive (46.41 MPa) fracture strength, favorable tensile (6.05 MJ m−3) and compressive (3.08 MJ m−3) toughness, antifreezing property (−30 °C) and high conductivity (2.86 S m−1). Based on the above characteristics, the hydrogel is applied for strain sensor to monitor the joints motion of human body such as finger, wrist, elbow, knee, neck, and throat. The hydrogel can maintain good mechanical performance and stable sensing signal from 25 to −30 °C. Therefore, the designed hydrogel based on natural polymers shows a huge potential for tissue engineering and biosensing under the mild or extreme environment.

Pressure sensors have attracted worldwide attention due to their extensive application requirements in wearable devices, flexible touch display, soft robotics, and health monitoring. Although many pressure sensors have been developed, it still remains a grand challenge to achieve ultrahigh sensitivity with good stability in low‐pressure regions. Herein, the polypyrrole (PPy) is introduced to reduced graphene oxide foam (rGOF) via in situ solventless polymerization to manufacture rGO/PPyF, which significantly enhances the sensitivity and stability of the derived sensors. The as‐fabricated sensor demonstrates an ultrahigh sensitivity of 32.32 kPa−1 in the pressure region of 0–21 Pa, high resolution, and excellent cycling stability. Furthermore, the pressure sensor can transform different hand gestures to distinguishable electrical signals in sign language translation, which indicates that the pressure sensor has a bright application prospect in wearable devices and human–computer interaction.

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5Chemical fixation of carbon dioxide (CO2) to cyclic carbonates were investigated by using bifunctional nucleophile-electrophile catalysts of metallophthalocyanine-carbon nitride hybrid [MPc/g-C3N4 (M = Co, Cu)] in the absence of any co-catalysts and organic solvents. MPc/g-C3N4 was readily obtained by a direct calcination of mixture of dicyandiamide and metallophthalocyanine under flowing-nitrogen atmosphere, and the MPc/g-C3N4 prepared at 480 °C (MPc/g-C3N4-480) showed the highest catalytic performance 10 toward the cycloaddition reaction of CO2 to epichlorohydrin (ECH). For bifunctional MPc/g-C3N4, MPc species function as Lewis acidic center for ECH activation via electrophilic attack; while, g-C3N4 moiety, possessing abundant and uncondensed species with the forms of primary amine (NH2) groups and secondary amine (C-NH-C) groups at the edges of graphitic sheets as edge defects, acts as organic base for CO2 activation through nucleophilic attack. The developed MPc/g-C3N4 is stable and insoluble in any 15 commonly used organic solvents and behaves as heterogeneous catalyst, leading to a facile separation and recycling in CO2 fixation reaction. 75 Hybrid materials of metallophthalocyanine and carbon nitride are recyclable catalysts for CO2 fixation to cyclic carbonate.