Hierarchically porous carbon is synthesized from PET using ZnCl2/NaCl, exhibiting a high evaporation rate (1.68 kg m−2 h−1) and energy conversion efficiency (97%).

No abstract

Stimulus-responsive hydrogels are of great significance in soft robotics, wearable electronic devices, and sensors. Near-infrared (NIR) light is considered an ideal stimulus as it can trigger the response behavior remotely and precisely. In this work, a smart flexible stimuli-responsive hydrogel with excellent photothermal property and decent conductivity are prepared by incorporating MXene nanosheets into the physically cross-linked poly(N-isopropyl acrylamide) hydrogel matrix. Because of outstanding photothermal effect and dispersion of MXene, the composite hydrogel exhibits rapid photothermal responsiveness and excellent photothermal stability under the NIR irradiation. Furthermore, the anisotropic bilayer hydrogel actuator shows fast and controllable light-driven bending behavior, which can be used as a light-controlled soft manipulator. Meanwhile, the hydrogel sensor exhibits cycling stability and good durability in detecting various deformation and real-time human activities. Therefore, the present study involving the fabrication of MXene nanocomposite hydrogels for potential applications in remotely controlled actuator and wearable electronic device provides a new method for the development of photothermal responsive conductive hydrogels.

The intrinsic hydrophobicity, deficient light absorption of solar energy, and the energy loss from the radiation relaxation of charges that decreases the solar–thermal conversion efficiency, have severely hindered the application of conjugated polymers in solar steam generation. Here, the construction of a donor–acceptor system constituted by a superhydrophilic covalent triazine framework (CTF) and carbon nanotube (CNT), which can enhance the water extraction and supply, was reported to effectively suppress the energy loss via controllable charge migration. The resulting donor–acceptor charge migration system could not only extend light harvesting but also increase energy conversion efficiency by decreasing undesired radiation relaxation, and hence it delivers a high performance in solar steam generation with a rate of 1.59 kg m–2 h–1 and a solar thermal conversion efficiency of 93.2% under 1 sun irradiation. This work provides a convenient strategy and new mechanism to improve the solar thermal conversion of the porous organic semiconductors.

Solar vapor generation is emerging as a promising technology using solar energy for various applications including desalination and freshwater production. However, from the viewpoints of industrial and academic research, it remains challenging to prepare low-cost and high-efficiency photothermal materials. In this work, we report the controlled carbonization of polypropylene (PP) using NiO and poly(ionic liquid) (PIL) as combined catalysts to prepare a Ni/carbon nanomaterial (Ni/CNM). The morphology and textural property of Ni/CNM are modulated by adding a trace amount of PIL. Ni/CNM consists of cup-stacked carbon nanotubes (CS-CNTs) and pear-shaped metallic Ni nanoparticles. Due to the synergistic effect of Ni and CS-CNTs in solar absorption, Ni/CNM possesses an excellent property of photothermal conversion. Meanwhile, Ni/CNM with a high specific surface area and rich micro-/meso-/macropores constructs a threedimensional (3D) porous network for efficient water supply and vapor channels. Thanks to high solar absorption, fast water transport, and low thermal conductivity, Ni/CNM exhibits a high water evaporation rate of 1.67 kg m −2 h −1 , a solar-to-vapor conversion efficiency of 94.9%, and an excellent stability for 10 cycles. It also works well when converting dyecontaining water, seawater, and oil/water emulsion into healthy drinkable water. The metallic ion removal efficiency of seawater is 99.99%, and the dye removal efficiency is >99.9%. More importantly, it prevails over the-state-of-art carbonbased photothermal materials in solar energy-driven vapor generation. This work not only proposes a new sustainable approach to convert waste polymers into advanced metal/ carbon hybrids, but also contributes to the fields of solar energy utilization and seawater desalination.