Yolk-like non-stoichiometric nickel sulfide-based Janus hydrogel photothermal film for enhanced solar-driven water evaporation and multi-media purification

A 3D self-floating solar vapor generator based on a novel self-healing aero-hydrogel containing peach gum polysaccharide with durability and continuous operation

Solar energy interfacial evaporation represents a promising and sustainable approach with considerable potential for seawater desalination and wastewater treatment. Nonetheless, creating durable evaporators for continuous operation presents a challenge. Motivated by natural self-healing mechanisms, this study developed a novel 3D hybrid aero-hydrogel, which exhibited a self-healing efficiency of 89.4 % and an elongation at break post-healing of 637.7 %, featuring self-healing capabilities and continuous operation potential. Especially, the incorporation of hyperbranched water-soluble polymers (peach gum polysaccharide) endow the final solar water evaporators with a lower evaporation enthalpy of water, resulting in that the refined SVG3, with a notable water surface architecture and an expanded evaporation area, achieved a steam generation rate of 2.13 kg m-2 h-1 under 1 Sun. Notably, SVG2 achieved a high evaporation rate of 2.43 kg m-2 h-1 with the combined energy input of 1 Sun and 6 V, significantly surpassing the rate of 1.96 kg m-2 h-1 without voltage input. The results indicate that electrical energy significantly enhances and synergizes with SVG, facilitating continuous operation both day and night through the combined use of solar energy and electrical input. This study offers insightful perspectives for the strategic design of multifunctional hydrogels for solar water evaporation.

A Tent-Inspired Portable Solar-Driven Water Purification Device for Wilderness Explorers

Wilderness adventure favored by many enthusiasts often endanger lives due to lacking freshwater or drinking contaminated water. Therefore, compared to the inefficient methods of filtration, steaming, and direct solar heating, it is of great meaningfulness to develop a solar-driven water purification device with efficiency, lightweight, portability, and multi-water-quality purification by taking full advantage of solar-driven interfacial evaporation. Here, a tent-inspired portable solar-driven water purification device consisting of Janus-structured bacterial cellulose aerogel (JBCA) solar evaporator and tent-type condensation recovery device is reported. For the JBCA solar evaporator, it is prepared from biomass bacterial cellulose (BC) as raw material and hydroxylated carbon nanotubes (HCNT) as photothermal material, and the Janus property is achieved by the assistance of hydrophobic and hydrophilic chemical cross-linking. It exhibits lightweight, unibody, high photothermal conversion, efficient evaporation, and multi-water-quality purification capability for representative seawater, urine, and bacterial river water. For the tent-type condensation recovery device, it is based on the prototype of tent and uses flexible ultra-transparent polyvinyl chloride (PVC) film as raw material. Thanks to the rational prototype and material selection, it displays outstanding portability and lightweight through the folding/unfolding method. Therefore, the designed tent-inspired portable solar-driven water purification device demonstrates great potential application in wilderness exploration.

Janus structure hydrogels: recent advances in synthetic strategies, biomedical microstructure and (bio)applications

Janus structure hydrogels (JSHs) are novel materials. Their primary fabrication methods and various applications have been widely reported. JSHs are primarily composed of Janus particles (JNPs) and polysaccharide components. They exhibit two distinct physical or chemical properties, generating intriguing characteristics due to their asymmetric structure. Normally, one side (adhesive interface) is predominantly constituted of polysaccharide components, primarily serving excellent adhesion. On the other side (functional surface), they integrate diverse functionalities, concurrently performing a plethora of synergistic functions. In the biomedical field, JSHs are widely applied in anti-adhesion, drug delivery, wound healing, and other areas. It also exhibits functions in seawater desalination and motion sensing. Thus, JSHs hold broad prospects for applications, and they possess significant research value in nanotechnology, environmental science, healthcare, and other fields. Additionally, this article proposes the challenges and future work facing these fields.

Enhanced Oxygen Evolution Reaction Performance on NiSx@Co3O4/Nickel Foam Electrocatalysts with Their Photothermal Property

Based on the principle of heterogeneous catalysis for water electrolysis, electrocatalysts with appropriate electronic structure and photothermal property are expected to drive the oxygen evolution reaction effectively. Herein, amorphous NiS_x-coupled nanourchin-like Co₃O₄ was prepared on nickel foam (NiS_x@Co₃O₄/NF) and investigated as a electrocatalyst for photothermal-assisted oxygen evolution reaction. The experimental investigations and simulant calculations jointly revealed NiS_x@Co₃O₄/NF to be of suitable electronic structure and high near-infrared photothermal conversion capability to achieve the oxygen evolution reaction advantageously both in thermodynamics and in kinetics. Relative to Co₃O₄/NF and NiS_x/NF, better oxygen evolution reaction activity, kinetics, and stability were achieved on NiS_x@Co₃O₄/NF in 1.0 M KOH owing to the NiS_x/Co₃O₄ synergetic effect. In addition, the oxygen evolution reaction performance of NiS_x@Co₃O₄/NF can be obviously enhanced under near-infrared light irradiation, since NiS_x@Co₃O₄ can absorb the near-infrared light to produce electric and thermal field. For the photothermal-mediated oxygen evolution reaction, the overpotential and Tafel slope of NiS_x@Co₃O₄/NF at 50 mA cm^-2 were reduced by 23 mV and 13 mV/dec, respectively. The present work provides an inspiring reference to design and develop photothermal-assisted water electrolysis using abundant solar energy.

A multifunctional hydrogel dressing with antibacterial properties for effective wound healing

We have developed a multifunctional hydrogel dressing (denoted as dressing-2 : 1) using silver-doped yolk-like nickel sulfide (Ag(8.5%)@NiS_2-x), polyacrylamide (PAM), and chitosan (CS). Ag(8.5%)@NiS_2-x has tremendous potential in antibacterial applications mainly due to the following advantages: (i) it has excellent optical absorption in the 200-2500 nm range and can be combined with near-infrared laser for photothermal therapy; (ii) it possesses peroxidase characteristic, which can catalyze low-concentration hydrogen peroxide to produce highly effective bactericidal hydroxyl radicals; (iii) silver doping gives it the ability to destroy the inherent components of bacteria. Moreover, the PAM/CS hydrogel can adsorb both bacteria and inflammatory secretions, enhancing the sterilization ability of Ag(8.5%)@NiS_2-x and promoting tissue healing. Our work highlights the great potential of dressing-2 : 1 as a multifunctional hydrogel dressing for effective antibacterial wound healing.