Nitrogen-Doped Carbon Nanofiber/Molybdenum Disulfide Nanocomposites Derived from Bacterial Cellulose for High-Efficiency Electrocatalytic Hydrogen Evolution Reaction

To remit energy crisis and environmental deterioration, non-noble metal nanocomposites have attracted extensive attention, acting as a fresh kind of cost-effective electrocatalysts for hydrogen evolution reaction (HER). In this work, hierarchically organized nitrogen-doped carbon nanofiber/molybdenum disulfide (pBC-N/MoS₂) nanocomposites were successfully prepared via the combination of in situ polymerization, high-temperature carbonization process, and hydrothermal reaction. Attributing to the uniform coating of polyaniline on the surface of bacterial cellulose, the nitrogen-doped carbon nanofiber network acts as an excellent three-dimensional template for hydrothermal growth of MoS₂ nanosheets. The obtained hierarchical pBC-N/MoS₂ nanocomposites exhibit excellent electrocatalytic activity for HER with small overpotential of 108 mV, high current density of 8.7 mA cm^–2 at η = 200 mV, low Tafel slope of 61 mV dec^–1, and even excellent stability. The greatly improved performance is benefiting from the highly exposed active edge sites of MoS₂ nanosheets, the intimate connection between MoS₂ nanosheets and the highly conductive nitrogen-doped carbon nanofibers and the three-dimensional networks thus formed. Therefore, this work provides a novel strategy for design and application of bacterial cellulose and MoS₂-based nanocomposites as cost-effective HER eletrocatalysts

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

4D-Printed Bionic Soft Robot with Superior Mechanical Properties and Fast Near-Infrared Light Response

Inspired by natural organisms, a four-dimensional (4D)-printed starfish-like bionic soft robot (SBSR) was effectively prepared by integrating three-dimensional (3D) printing with smart hydrogels. The body of the SBSR is composed of a reduced graphene oxide-poly(N-isopropylacrylamide) hydrogel (rGO-PNH) with superior mechanical properties. In addition, the enhanced photothermal conversion effect was obtained by the reduction of graphene oxide nanosheets after the 3D printing process. Cylindrical actuators prepared using rGO-PNH exhibited bending and orientation toward the light source within 20 s of exposure to near-infrared light, thus demonstrating the rapid photoresponsivity of rGO-PNH. Furthermore, the 4D-printed SBSR showcased effective grasping, lifting, and releasing of objects by mimicking the predatory behavior of starfish. This study would provide insights into the development of responsive materials in 4D printable bionic soft robots and their applications in areas such as biomimetic devices and artificial muscles

Highly stable manganese oxide cathode material enabled by Grotthuss topochemistry for aqueous zinc ion batteries

The design and synthesis of manganese oxide-based  materials with high-rate performance and long cycle life is a major  challenge for aqueous zinc-ion batteries (AZIBs). This research reports  the presence of a synergistic collaboration between vacancies, lattice  water and nickel ions on enhancing the hydrated protons hopping via  the Grotthuss mechanism for high-performance zinc ion batteries. The  Grotthuss mechanism allows for the efficient transfer of a proton charge  without the actual movement of the molecule over long distances,  resulting in high ionic conductivity. NiMn3O7·3H2O achieves a capacity of 318 mA h g−1 under 200 mA g−1 and 121 mA h g−1 under 5 A g−1  with a retention of 91% after 4000 cycles. The relationship between the  remarkable performance and Grotthuss topochemistry is investigated  using techniques including synchrotron X-ray absorption spectroscopy and  density functional theory. Protons prefer to bond with O2−  ions on the Mn–O layer, and proton transfer is favoured in the presence  of vacancies. The continuous hopping of protons within the host  material induces periodic, temporary local structural changes in the  lattice. This dynamic behaviour alters the energy barriers for ions  intercalation and deintercalation. Nickel ions facilitate the ongoing  mobility of hydrated protons via Grotthuss  hopping by preserving the system's electrical neutrality, which  counterbalances the dynamic changes caused by proton migration. This  study provides insight into the Grotthuss conduction mechanism for the  development of high-performance cathode materials in AZIBs.</p

Langmuir–Blodgett Film Formed by Amphiphilic Molecules for Facile and Rapid Construction of Zinc–Iodine Cell

Zinc–iodine batteries (ZIBs) are promising candidates for ecofriendly, safe, and low-cost energy storage systems, but polyiodide shuttling and the complex cathode fabrication procedures have severely hindered their broader commercial usage. Herein, a protocol is developed using phospholipid-like oleylamine molecules for scalable production of Langmuir–Blodgett films, which allows the facile preparation of ZIB cathodes in less than 1 min. The resulting inhomogeneous cathode allows for the continuous conversion of iodine. Moreover, the amine group of the oleylamine molecule at the cathode is capable of producing [OA*I+]I3– charge-transfer complexes with iodine, which facilitates the rapid migration of iodine and results in a highly reversible iodine conversion process. Consequently, the as-prepared ZIBs can deliver over 2000 cycles at 0.5 mA cm–2 with a capacity retention of 75.3%. This work presents a novel, straightforward, and efficient method for the rapid construction of ZIBs