Fog collection is receiving increasing attention for providing water in semi-arid deserts and inland areas. Inspired by the fog harvesting ability of the hydrophobic-hydrophilic surface of Namib desert beetles, we present a simple, low-cost method to prepare a hybrid superhydrophobic-hydrophilic surface. The surface contains micro/nanopatterns, and is prepared by incorporating femtosecond-laser fabricated polytetrafluoroethylene nanoparticles deposited on superhydrophobic copper mesh with a pristine hydrophilic copper sheet. The as-prepared surface exhibits enhanced fog collection efficiency compared with uniform (super)hydrophobic or (super)hydrophilic surfaces. This enhancement can be tuned by controlling the mesh number, inclination angle, and fabrication structure. Moreover, the surface shows excellent anti-corrosion ability after immersing in 1 M HCl, 1 M NaOH, and 10 wt% NaCl solutions for 2 hours. This work may provide insight into fabricating hybrid superhydrophobic-hydrophilic surfaces for efficient atmospheric water collection.
Marine oil spills have induced severe water pollution and threatened sea ecosystems, which also result in a loss of energy resources. To deal with this problem, much work has been done for using superhydrophobic or superhydrophilic mesh for oil-water separation. Nevertheless, there are still great challenges in the rapid fabrication of extremely durable mesh with superwetting properties, particularly considering the highly efficient oil-water separation. In this study, we present a simple, efficient method to fabricate superhydrophilic and underwater superoleophobic stainless steel mesh surfaces with one-step femtosecond laser induced periodic nanoripple structures. The as-prepared mesh shows high separation efficiency, which is higher than 99% for various oil-water mixtures. More importantly, the wettability and the separation efficiency of the fabricated mesh show no obvious change after the abrasion tests and corrosion tests, indicating that the as-prepared samples possess robust stability. This study provides an efficient route for constructing durable and highly efficient separation mesh, which can be applied in the cleanup of large-scale oil spills in the near future.
Van der Waals (vdW) dielectrics such as hBN are widely used to preserve the intrinsic properties of twodimensional (2D) semiconductors and support the fabrication of high-performance 2D devices. This is fundamentally attributed to their dangling-bond-free surface, carrying far lower density of charged scattering sources and trap states with respect to the conventional dielectrics (SiO 2 etc.). However, their wafer-scale fabrication and compatible integration with 2D semiconductors remain cumbersome, giving rise to the di culties in scalable fabrication of high-performance 2D devices. Here we report a high-κ vdW dielectric (ε r =11.5) composed of inorganic molecular crystal (IMC) Sb 2 O 3 , allowing for large-scale fabrication and facile integration via standard thermal evaporation process thanks to its particular crystal structure. Similarly, our vdW dielectric also supports remarkably improved 2D devices with respect to the typical conventional dielectric SiO 2 . The monolayer MoS 2 eld effect transistors (FET) supported by our vdW dielectric exhibits high on/off ratio (10 8 ), greatly enhanced electron mobility (from 20 to 80 cm 2 /Vs) and reduced transfer-curve hysteresis over an order of magnitude. Our results may open a new avenue towards compatible fabrication of vdW dielectrics using IMCs and lead to the scalable fabrication of high-performance 2D devices.
Bimetallic sulfides are expected to realize efficient CO 2 electroreduction into formate over aw ide potential window,however,they will undergo in situ structural evolution under the reaction conditions.T herefore,c larifying the structural evolution process,t he real active site and the catalytic mechanism is significant. Here,taking Cu 2 SnS 3 as an example, we unveiled that Cu 2 SnS 3 occurred self-adapted phase separation towardf orming the stable SnO 2 @CuS and SnO 2 @Cu 2 O heterojunction during the electrochemical process.C alculations illustrated that the strongly coupled interfaces as real active sites driven the electron self-flow from Sn 4+ to Cu + , therebypromoting the delocalized Sn sites to combine HCOO* with H*. Cu 2 SnS 3 nanosheets achieve over 83.4 %f ormate selectivity in awide potential range from À0.6 VtoÀ1.1 V. Our findings provide insight into the structural evolution process and performance-enhanced origin of ternary sulfides under the CO 2 electroreduction.
Metal oxides are archetypal CO2 reduction reaction electrocatalysts, yet inevitable self-reduction will enhance competitive hydrogen evolution and lower the CO2 electroreduction selectivity. Herein, we propose a tangible superlattice model of alternating metal oxides and selenide sublayers in which electrons are rapidly exported through the conductive metal selenide layer to protect the active oxide layer from self-reduction. Taking BiCuSeO superlattices as a proof-of-concept, a comprehensive characterization reveals that the active [Bi2O2]2+ sublayers retain oxidation states rather than their self-reduced Bi metal during CO2 electroreduction because of the rapid electron transfer through the conductive [Cu2Se2]2- sublayer. Theoretical calculations uncover the high activity over [Bi2O2]2+ sublayers due to the overlaps between the Bi p orbitals and O p orbitals in the OCHO* intermediate, thus achieving over 90% formate selectivity in a wide potential range from −0.4 to −1.1 V. This work broadens the studying and improving of the CO2 electroreduction properties of metal oxide systems.
Tandem catalysts can divide the reaction into distinct steps by local multiple sites and thus are attractive to trigger CO2RR to C2+ products. However, the evolution of catalysts generally exists during CO2RR, thus a closer investigation of the reconstitution, interplay, and active origin of dual components in tandem catalysts is warranted. Here, taking AgI−CuO as a conceptual tandem catalyst, we uncovered the interaction of two phases during the electrochemical reconstruction. Multiple operando techniques unraveled that in situ iodine ions leaching from AgI restrained the entire reduction of CuO to acquire stable active Cu0/Cu+ species during the CO2RR. This way, the residual iodine species of the Ag matrix accelerated CO generation and iodine‐induced Cu0/Cu+ promotes C−C coupling. This self‐adaptive dual‐optimization endowed our catalysts with an excellent C2+ Faradaic efficiency of 68.9 %. Material operando changes in this work offer a new approach for manipulating active species towards enhancing C2+ products.
We report a simple, efficient method to fabricate micro/nanoscale hierarchical structures on one side of polytetrafluoroethylene mesh surfaces, using one-step femtosecond laser direct writing technology. The laser-treated surface exhibits superhydrophobicity in air and superaerophilicity in water, resulting in the mesh possessing the hydrophobic/superhydrophobic asymmetrical property. Bubbles can pass through the mesh from the untreated side to the laser-treated side but cannot pass through the mesh in the opposite direction. The asymmetrical mesh can therefore be designed for the directional transportation and continuous collection of gas bubbles in aqueous environments. Furthermore, the asymmetrical mesh shows excellent stability during corrosion and abrasion tests. These findings may provide an efficient route for fabricating a durable asymmetrical mesh for the directional and continuous transport of gas bubbles.
In this paper, we present a rapid and simple method to fabricate superaerophilic polytetrafluoroethylene cones via a two-step femtosecond laser direct writing technique, which enormously improved processing efficiency compared to the existing method. The laser-treated cones contained hierarchical microstructures and exhibited self-driven and directional transport of gas bubbles along the cones and away from the tip, even when the cones were horizontal. Furthermore, the laser-treated cones exhibited excellent chemical and long-term stability. This work may provide an effective and simple approach to obtain efficient manipulation of gas bubbles in practical applications.
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