Search

Atmospheric water harvesting (AWH) is regarded as one of the promising strategies for freshwater production desirable to provide sustainable water for landlocked and arid regions. Hygroscopic materials have attracted widespread attention because of their water harvesting performance. However, the introduction of many inorganic salts often leads to aggregation and leakage issues in practical use. Here, polyzwitterionic hydrogels are developed as an effective AWH material platform. Via anti‐polyelectrolyte effects, the hygroscopic salt coordinated with polymer chains could capture moisture and enhance the swelling property, leading to a strong moisture sorption capacity. The hydrogel shows superior AWH performance (0.62 g g−1, 120 minutes for equilibrium at 30 % relative humidity) and produces 5.87 L kg−1 freshwater per day. It is anticipated that the polyzwitterionic hydrogels with unique salt‐responsive properties could provide new insights into the design and synthesis of next‐generation AWH materials. [ABSTRACT FROM AUTHOR]

As an eco‐friendly means, solar water purification has attracted substantial research interest regarding material design, system engineering, and energy management. However, the low water yield and relatively high cost essentially restrict its practical potential. Here, a hydrogel‐based ultrathin membrane (HUM) is developed to synergistically coordinate facilitated vapor transfer and environmental energy harvesting for solar‐driven membrane distillation. The evaporation front is directly exposed to an airflow, which fundamentally eliminates the temperature polarization induced energy consumption. As such, the humidity of the output flow is significantly increased, and thus the vapor collection ratio rises to over 80% to achieve a high water yield of 2.4 kg m–2 h–1 under one sun without any energy recycling and cooling accessories. The HUM with a raw material cost of $0.36 m–2 offers a competitive potential cost of freshwater production of about $0.3–1.0 m–3. This work demonstrates a promising membrane distillation strategy based on sustainable energy toward both decentralized water purification and large‐scale water treatment. [ABSTRACT FROM AUTHOR]

The broad application of metal-air batteries and fuel cells have been greatly limited due to their slow kinetics of oxygen electrodes involving the oxygen reduction reaction (ORR), and therefore the development of high-efficient, low-cost and high-reserve ORR electrocatalysts is of great significance. Herein, a hypersaline-protected pyrolysis strategy is presented for preparing 3D honeycombed cobalt, nitrogen co-doped carbon nanosheets (Co/N-CNS) by using eco-friendly biomass as a carbon and nitrogen source. During the hypersaline-protected pyrolysis, the pyridinic nitrogen-rich biomass facilitates the formation of highly active Co/N active sites among the resultant Co/N-CNS, while the templating-washing-drying cyclic utilization of salts creates honeycombed pore structures among the Co/N-CNS. Due to the structural features of honeycombed pores and uniform distributed active sites, the Co/N-CNS catalyst offers excellent ORR activity, high durability and methanol-tolerant performance in an alkaline electrolyte. As a demonstration, a primary Zn-air battery using the Co/N-CNS cathode delivers a high power density and excellent operating stability beyond that of commercial Pt/C cathode. [ABSTRACT FROM AUTHOR]

Abstract: A simple, low cost and nontoxic preparation method to obtain high performance oxygen reduction reaction (ORR) catalysts is of great significance in fuel cell fields. Herein, graphene nanoribbons (GNRs) with numerous graphitic edges are chosen as supporting material to hybridize with nitrogen atoms and cobalt oxide (Co3O4) through a simple one‐step hydrothermal reaction. With a high edge‐to‐plane ratio, the GNR sheets could increase the accessibility of N‐atom doping into the graphene edges to form active ORR sites, and be also interconnected with each other to form a conductive network, thus facilitating the fast electron transfer. The intimate contacts between Co3O4 nanoparticles and nitrogen‐doped GNRs (N‐GNRs) along with the porous structure impart the N‐GNR/Co3O4 hybrid with excellent ORR performance, which leads to a comparable onset‐potential to commercial Pt/C catalyst but larger current density, better long‐term stability and superior tolerance to crossover effects. [ABSTRACT FROM AUTHOR]

It is very important to develop a simple, efficient, and scaleable method for detection of dopamine (DA) with high sensitivity and selectivity to diagnose some serious neurological diseases. Herein, electro-catalysts for detection of DA are simply prepared based on Fe2O3 nanoparticles (NPs) decorated on highly porous carbon aerogels (CAs), which are derived from KOH activated graphene-polyimide aerogels. In the hierarchical nanocomposites (NCs), CAs provide large specific surface area, abundant mesopores, and macropores, and many sites for in situ growth of Fe2O3 NPs, thus effectively preventing the aggregation of Fe2O3 NPs. Moreover, CAs with 3D interconnected porous structures are able to shorten the charge transfer pathways through the intimate interaction between CAs and Fe2O3 NPs. Therefore, when applied as electro-catalysts for detection of DA, the optimized NC exhibits rapid amperometric response and a low detection limit of 0.109 × 10−6 m (S/N = 3), with a wide linear concentration range from 5 to 500 × 10−6 m. In addition, the oxidation peak of DA can be readily distinguished from the interference of uric acid and ascorbic acid. Therefore, the highly porous CAs derived from KOH activated graphene-polyimide aerogels are excellent substrates for in situ growth of Fe2O3 NPs, exhibiting high electrocatalytic activity for DA detection. [ABSTRACT FROM AUTHOR]

Dopamine is an excellent and flexible agent for surface coating of various materials, with the high-concentration of amine groups serving as a facile stabilizer for some metallic nanoparticles. In this work, mesoporous composites of nitrogen-doped carbon fibers (NCFs) decorated with cobalt nanoparticles have been successfully fabricated via the combination of a mussel-inspired biomimetic polydopamine (PDA)-coating process using electrospun porous polystyrene fibers as templates, a simple solution deposition method and subsequent high-temperature carbonization. This rationally designed porous NCF–Co composite possesses a large surface area and numerous electrochemically active sites, which exhibits synergistically improved catalytic activity for oxygen reduction reactions (ORRs) with a relatively positive onset potential, large current density, as well as superior durability compared with the commercial platinum–carbon (Pt/C) catalyst, making it a promising noble-metal-free catalyst for practical ORR applications. [ABSTRACT FROM AUTHOR]

Increasing energy demands and worsening environmental issues have stimulated intense research on alternative energy storage and conversion systems including supercapacitors and fuel cells. Here, a rationally designed hierarchical structure of ZnCo2O4@NiCo2O4 core-sheath nanowires synthesized through facile electrospinning combined with a simple co-precipitation method is proposed. The obtained core-sheath nanostructures consisting of mesoporous ZnCo2O4 nanowires as the core and uniformly distributed ultrathin NiCo2O4 nanosheets as the sheath, exhibit excellent electrochemical activity as bifunctional materials for supercapacitor electrodes and oxygen reduction reaction (ORR) catalysts. Compared with the single component of either ZnCo2O4 nanowires or NiCo2O4 nanosheets, the hierarchical ZnCo2O4@NiCo2O4 core-sheath nanowires demonstrate higher specific capacitance of 1476 F g−1 (1 A g−1) and better rate capability of 942 F g−1 (20 A g−1), while maintaining 98.9 % capacity after 2000 cycles at 10 A g−1. Meanwhile, the ZnCo2O4@NiCo2O4 core-sheath nanowires reveal comparable catalytic activity but superior stability and methanol tolerance over Pt/C as ORR catalyst. The impressive performance may originate from the unique hierarchical core-sheath structures that greatly facilitate enhanced reactivity, and faster ion and electron transfer. [ABSTRACT FROM AUTHOR]

Hydrogels, membrane distillation, solar desalination, wastewater treatment, water production Keywords: hydrogels; membrane distillation; solar desalination; wastewater treatment; water production EN hydrogels membrane distillation solar desalination wastewater treatment water production 1 1 1 05/12/21 20210510 NES 210510 In article number 2101036, Fei Zhao, Chenyang Zhao, Guihua Yu, and co-workers develop a hydrogel-based ultrathin membrane (HUM) for solar water purification. The HUM can synergistically coordinate facilitated vapor transfer and environmental energy harvesting in a solar-driven membrane distillation system, leading to a significant water yield improvement under one sun without any energy recycling and cooling accessories. [Extracted from the article]

The bio-inspired hierarchical “grape cluster” superstructure provides an effective integration of one-dimensional carbon nanofibers (CNF) with isolated carbonaceous nanoparticles into three-dimensional (3D) conductive frameworks for efficient electron and mass transfer. Herein, a 3D N-doped porous carbon electrocatalyst consisting of carbon nanofibers with grape-like N-doped hollow carbon particles (CNF@NC) has been prepared through a simple electrospinning strategy combined with in-situ growth and carbonization processes. Such a bio-inspired hierarchically organized conductive network largely facilitates both the mass diffusion and electron transfer during the oxygen reduction reactions (ORR). Therefore, the metal-free CNF@NC catalyst demonstrates superior catalytic activity with an absolute four-electron transfer mechanism, strong methanol tolerance and good long-term stability towards ORR in alkaline media. [ABSTRACT FROM AUTHOR]

The development of strong-yet-ductile polymer nanocomposites is critical, but still faces a great challenge. Herein, a hybrid carbon nanofiller consisting of one-dimensional carbon nanotube (CNT) and two-dimensional graphene (G) was molecularly engineered, and the as-prepared G-CNT hybrid nanofiller was then solution-casted with thermoplastic polyurethane (TPU) for the fabrication of TPU nanocomposite films. Due to the formation of unique network structure with multiple interactions of G-CNT hybrid within TPU matrices, the as-fabricated TPU nanocomposites showed simultaneously improved mechanical strength and toughness. With addition of only 1 wt% G-CNT hybrid, the tensile strength and toughness of TPU/(G-CNT) nanocomposite reached 69.5 MPa and 246.2 MJ m−3, 1.9 and 2.9 times over that of neat TPU, respectively. The significant and simultaneous enhancement in mechanical strength and toughness of TPU nanocomposites is attributed to homogeneously distributed G-CNT hybrid and its unique energy dissipations due to factures at different deformation stages upon tensile deformation. The work therefore provides a simple and efficient strategy for fabricating mechanically strong and ductile polymer nanocomposites with molecular-engineered hybrid carbon nanofillers. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a degenerative bone and joint disease characterized by decreased cartilage lubrication, leading to continuous wear and ultimately irreversible damage. This situation is particularly challenging for early-stage OA, as current bio-lubricants lack precise targeting for small inflammatory lesions. In this work, an antibody-mediated targeting hydrogel microspheres (HMS) is developed to precisely lubricate the local injury site of cartilage and prevent the progression of early OA. Anti-Collagen type I (Anti-Col1) is an antibody that targets cartilage injury sites in early OA stages. It is anchored on a HMS matrix made of Gelatin methacrylate (GelMA) and poly (sulfobetaine methacrylate) (PSBMA) to create targeted HMS (T-G/S HMS). The T-G/S HMS's high hydrophilicity, along with the dynamic interaction between its surficial Anti-Col1 and the Col1 on cartilage injury site, ensures its precise and effective lubrication of early OA lesions. Consequently, injecting T-G/S HMS into rats with early OA significantly slows disease progression and reduces symptoms. In conclusion, the developed injectable targeted lubricating HMS and the precisely targeted lubrication strategy represent a promising, convenient technique for treating OA, particularly for slowing the early-stage OA progression., (© 2024 Wiley‐VCH GmbH.)

Solid-state electrolyte (SSE), as the core component of solid-state batteries, plays a critical role in the performance of the batteries. Currently, the development of SSE is still hindered by its high price, low ionic conductivity, and poor interface stability. In this work, we report the tailored synthesis of a high ionic conductive and low cost sulfide SSE for all-solid-state lithium batteries. The Li 10.35 Si 1.35 P 1.65 S 12 with favorable tetragonal structure was synthesis by increasing the concentration of Si 4+ , which shows an ionic conductivity of 4.28 × 10 -3  S cm -1 and a wide electrochemical stability window of up to 5 V. By further modifying the composition of the electrolyte via ionic doping, the ionic conductivity of Li 10.35 Si 1.35 P 1.65 S 12 can be further enhanced. Among them, the 1% Co 4+ -doped Li 10.35 Si 1.35 P 1.65 S 12 shows the highest ionic conductivity of 6.91 × 10 -3  S cm -1 , 40% higher than the undoped one. This can be attributed to the broadened MS 4 - tetrahedrons and increased Li + concentration. As a demonstration, an all-solid-state Li metal battery was assembled using TiS 2 as the cathode and 1% Co 4+ -doped Li 10.35 Si 1.35 P 1.65 S 12 as the electrolyte, showing capacity retention of 72% at the 110th cycle. This strategy is simple and can be easily extended for the construction of other high-performance sulfide SSEs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lin, Chen, Yan, Zhuang, Lu and Zhao.)

Atmospheric water harvesting (AWH) is regarded as one of the promising strategies for freshwater production desirable to provide sustainable water for landlocked and arid regions. Hygroscopic materials have attracted widespread attention because of their water harvesting performance. However, the introduction of many inorganic salts often leads to aggregation and leakage issues in practical use. Here, polyzwitterionic hydrogels are developed as an effective AWH material platform. Via anti-polyelectrolyte effects, the hygroscopic salt coordinated with polymer chains could capture moisture and enhance the swelling property, leading to a strong moisture sorption capacity. The hydrogel shows superior AWH performance (0.62 g g -1 , 120 minutes for equilibrium at 30 % relative humidity) and produces 5.87 L kg -1 freshwater per day. It is anticipated that the polyzwitterionic hydrogels with unique salt-responsive properties could provide new insights into the design and synthesis of next-generation AWH materials., (© 2022 Wiley-VCH GmbH.)

Water electrolysis is a promising approach for green and large-scale hydrogen production; however, there are still challenges for developing efficient and stable bifunctional electrocatalysts toward the hydrogen and oxygen evolution reactions. Herein, zeolitic imidazolate framework-67 was used as the precursor for the construction of CoSe 2 nanoparticles trapped in N-doped carbon (NC) polyhedra. Among as-obtained CoSe 2 -NC hybrid, highly active CoSe 2 nanoparticles in sizes of 10-20 nm are encapsulated in N-doped few-layer carbon shell, avoiding their easy aggregations of CoSe 2 nanoparticles as well as enhancing the long-term stability. The unique nanostructured CoSe 2 -NC hybrid with a hierarchical porosity and 3D conductive framework thus fully exerts outstanding bifunctional catalytic activity of CoSe 2 centers. As a result, the CoSe 2 -NC hybrid as bifunctional catalysts for overall water splitting delivers a high current density of 50 mA cm -2 with an applied voltage of ∼1.73 V in an alkaline electrolyte, with a promising stability over 50 000 s.

Recent studies have proven that newly emerging two-dimensional molybdenum diselenide (MoSe2) is a promising noble-metal-free electrocatalyst for hydrogen evolution reaction (HER). Increasing the exposures of the active edges of MoSe2 nanostructures is a key issue to fully realize the excellent electrochemical properties of MoSe2. In this work, a few-layered MoSe2/carbon fiber aerogel (CFA) hybrids have been facilely obtained through the combination of high-temperature carbonization and one-pot solvothermal reaction. CFA derived from cotton wool is used as a three-dimensional conductive network for construction of hierarchical MoSe2/CFA hybrids, where few-layered MoSe2 nanosheets are uniformly and perpendicularly decorated on the surfaces of CFA. In the designed and prepared hybrids, CFA effectively increases the exposures of the active edges of MoSe2 nanosheets as well as provides reduced lengths for both electron transportation and ion diffusion. Therefore, the obtained optimal MoSe2/CFA hybrid exhibits excellent electrochemical activity as HER electrocatalyst with a small onset potential of -0.104 V vs reversible hydrogen electrode and a small Tafel slope of 62 mV per decade, showing its great potential as a next-generation Pt-free electrocatalyst for HER.

Exploration of high-efficiency Pt-free electrochemical catalysts for hydrogen evolution reaction (HER) is considered as a great challenge for the development of sustainable and carbon dioxide free energy conversion systems. In this work, a unique hierarchical nanostructure of few-layered MoSe2 nanosheets perpendicularly grown on carbon nanotubes (CNTs) is synthesized through a one-step solvothermal reaction. This rationally designed architecture based on a highly conductive CNT substrate possesses fully exposed active edges and open structures for fast ion/electron transfer, thus leading to remarkable HER activity with a low onset potential of -0.07 V vs. RHE (reversible hydrogen electrode), a small Tafel slope of 58 mV per decade and excellent long-cycle stability. Therefore, this noble-metal-free and highly efficient catalyst enables prospective applications for industrial, renewable hydrogen production.

Increasing energy demands and worsening environmental issues have stimulated intense research on alternative energy storage and conversion systems including supercapacitors and fuel cells. Here, a rationally designed hierarchical structure of ZnCo2 O4 @NiCo2 O4 core-sheath nanowires synthesized through facile electrospinning combined with a simple co-precipitation method is proposed. The obtained core-sheath nanostructures consisting of mesoporous ZnCo2 O4 nanowires as the core and uniformly distributed ultrathin NiCo2 O4 nanosheets as the sheath, exhibit excellent electrochemical activity as bifunctional materials for supercapacitor electrodes and oxygen reduction reaction (ORR) catalysts. Compared with the single component of either ZnCo2 O4 nanowires or NiCo2 O4 nanosheets, the hierarchical ZnCo2 O4 @NiCo2 O4 core-sheath nanowires demonstrate higher specific capacitance of 1476 F g(-1) (1 A g(-1) ) and better rate capability of 942 F g(-1) (20 A g(-1) ), while maintaining 98.9 % capacity after 2000 cycles at 10 A g(-1) . Meanwhile, the ZnCo2 O4 @NiCo2 O4 core-sheath nanowires reveal comparable catalytic activity but superior stability and methanol tolerance over Pt/C as ORR catalyst. The impressive performance may originate from the unique hierarchical core-sheath structures that greatly facilitate enhanced reactivity, and faster ion and electron transfer., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)