ABSTRACT
Photothermal conversion materials are critical in the development of solar-driven interfacial evaporation techniques; however, achieving a high energy conversion efficiency remains challenging owing to the high cost and instability of light-absorbing materials, in addition to the difficulties of simultaneously improving light absorption while suppressing heat loss. A black silicon (Si) powder with a porous structure was prepared by chemical etching of a low-cost commercial micron-sized Al-Si alloy, and a flexible Janus black Si photothermal conversion membrane was constructed. The partially broken spherical particles and porous structure obtained after etching enhanced the refraction of light from the Si powder, imparting the prepared membrane with an average light absorption rate of 95.95% over the solar spectrum. Evaporation from the membrane increased the intermediate water content and reduced the equivalent evaporation enthalpy. The thermal conduction loss was inhibited through a one-dimensional water transport structure, and the membrane achieved a water evaporation rate of 2.17 kg m-2 h-1 and a photothermal efficiency of 94.95% under 1 sun illumination. Benefiting from the broadband absorption and high photothermal efficiency of black Si powder, surface modification of hydrophobic polydimethylsiloxane, and directional salt-out structure design, the evaporation rate of the Janus black Si membrane-based system in a 10% NaCl solution was maintained >2.10 kg m-2 h-1 after 7 days of continuous evaporation cycles. The removal rate of metal ions from simulated seawater and from practical wastewater containing complex heavy metals reached >99.9%, indicating the promising potential of black Si membrane for application in solar-driven interfacial water purification.
ABSTRACT
Chloride ion (Cl-), one of the most important anions in the brain, has been confirmed to participate in the pathological process of Parkinson's disease (PD). As such, the development of a reliable method for in vivo measurements of Cl- is extremely appealing, especially for understanding the pathogenesis of PD. We herein designed a facile electrochemical microbiosensor (ECMB), based on in situ self-assembly of Ag nanoparticles (Ag NPs) coated on Ti3C2Tx. The uniform nanosized Ag NPs were reduced by Ti3C2Tx by a simple dipping process, endowing the ECMB with excellent specificity toward Cl- detection and remarkably reproducible preparation process. Meanwhile, electro-oxidized graphene oxide was introduced as an inner reference, thus avoiding the environmental interference of the complicated brain systems to increase the determination accuracy. An extensive in vitro study revealed that the proposed ECMB would be a robust candidate for real-time monitoring of Cl- in the PD mouse brain with high selectivity, accuracy, and reproducibility. Moreover, the availability and reliability toward in vivo Cl- monitoring of the designed ECMB were well confirmed by comparing with the standard Volhard's method. Finally, by virtue of the successful employment of the developed detecting platform in the in vivo measurement of Cl- in the PD mouse brain, systematic analysis and comparison of the average levels of Cl- in the three regions including cortex, striatum, and hippocampus of brains from normal and PD model mice have been achieved.
Subject(s)
Metal Nanoparticles , Parkinson Disease , Animals , Brain , Chlorides , Electrochemical Techniques , Mice , Reproducibility of Results , Silver , TitaniumABSTRACT
Manganese-based transition metal oxides are regarded as one kind of high capacity and low cost anode material for Li-ion batteries. To overcome the challenges of poor electrical conductivity and large volumetric expansion during the charging-discharging process of MnO, we here synthesize MnO@carbon (MnO@C) nanowires via the polymerization inspired in situ growth of [Mn-NTA] (NTA = nitrilotriacetic acid) precursor nanowires with a subsequent heat treatment process. The growth mechanism of [Mn-NTA] precursor nanowires was studied. The morphology of the precursor nanowires depended largely on the molar ratio of MnCl2 to NTA reactants. At a molar ratio of 2, the length of the [Mn-NTA] nanowires reached up to more than 140 µm. Furthermore, the as-synthesized MnO@C nanowires were integrated with a very low content of reduced graphene oxide (rGO) to prepare a self-standing paper-like MnO@C/rGO anode for lithium ion batteries without a binder. The MnO@C/rGO anode showed a unique structure with one-dimensional porous MnO nanowires hierarchically encapsulated by a conductive carbon framework. As a result, the self-standing electrode achieved a high capacity of 1368 mA h g-1 after 100 cycles at a current density of 100 mA g-1 and prominent cycling stability with a capacity of 689.9 mA h g-1 even after 1700 cycles at 2000 mA g-1.
