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Recently, semiconductor wastewater treatment has received much attention due to the emergence of environmental issues. Acid-resistant coatings are essential for metal prefilters used in semiconductor wastewater treatment. Perfluoroalkoxy alkane is mainly used as an acid-resistant coating agent, since PFA has inherent superhydrophobicity, water permeability is lowered. To solve this problem, the surface of the PFA-coated metal mesh was treated via an oxyfluorination method in which an injected mixed gas of fluorine and oxygen reacted with the surface functional groups. Surface analysis, water contact angle measurement, and water permeability tests were performed on the surface-treated PFA-coated mesh. Consequently, the superhydrophobic surface was effectively converted to a hydrophobic surface as the PFA coating layer was surface-modified with C-O-OH functional groups via the oxyfluorination reaction. As a result of using simulation solutions that float silica particles of various sizes, the permeability and particle removal rate of the surface-modified PFA-coated stainless-steel mesh were improved compared to those before surface modification. Therefore, the oxyfluorination treatment used in this study was suitable for improving the filtration performance of SiO2 microparticles in the PFA-coated stainless-steel mesh. [ABSTRACT FROM AUTHOR]

Summary: Construction of hybrid supercapacitors (HSCs) with defect engineered electrodes derived from single metal‐organic frameworks (zeolitic imidazolate frameworks, ZIF‐67) via control of the thermal influences showed unique structural features and rich electrochemical properties. Designing the three‐dimensional Co oxysulfide nanograins with carbon frame (CoOS‐C)‐based positive electrode surfaces through sulfidation with tunable defect states along with N‐ and S‐doping states improved the electrical energy storage; further, the possibility of having a carbon‐based skeleton surface influenced the effective rate capability during the charge‐discharge process. This unique nanostructural feature with encapsulation of porous N‐ and S‐doped graphitic carbon enabled improved rate performance by enhancing the stability of the electrode material and shortening the ion‐diffusion paths by the synergistic effect. Owing to the tunable defect functionality, the CoOS‐C based electrode exhibited a high storage capacity of 708.8 C g−1 at 1 A g−1 and an excellent rate capability with long‐term cyclic stability, with more than 93% capacity retention after 3000 cycles. Furthermore, the fabricated HSCs operated within a wide potential window of 1 to 1.6 V, which allowed excellent rate capability with a high‐energy density of 31.7 W h kg−1 at a specific power density of 800 W kg−1 with long‐term cyclic stability up to 10 000 cycles. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting represents an ideal strategy for producing clean hydrogen as an energy carrier that serves as an alternative to fossil fuels. As an effective method for hydrogen production, an efficient inexpensive multifunctional electrocatalyst with high durability is designed. Herein, we describe the heterostructural design of a three-dimensional catalytic network with self-embedded CoNi2S4 nanograins grown on electrospun carbon nanofibers (CoNi2S4–CNFs) with anchored thin-layer reduced graphene oxide. This is achieved via facile electrospinning followed by carbonization, low-temperature sulfidation, and surface functionalization. As a bifunctional catalyst, CoNi2S4–CNFs exhibited robust high activity toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. The anchored ultrathin graphene oxide layer promoted the stability and durability of the catalytic network with an efficient path for the transportation of electrons. The rGO-anchored CoNi2S4–CNFs yielded overpotential values of 228 mV and 205 mV for the HER and OER, respectively, that drives a current density of 20 mA cm−2 in an alkaline medium. Notably, the excellent electrochemical properties are attributed to the functional effect of the CoNi2S4 on the CNF network. The ultrathin feature of rGO improved the durability of the catalytic network. Moreover, using the rGO-anchored CoNi2S4–CNFs as a cathode and anode in a two-electrode water splitting system required a cell voltage of only 1.55 V to reach a current density of 10 mA cm−2. These CNFs exhibited outstanding durability for 48 h. The present work offers new insight for the design of a catalytic network with a non-noble metal catalyst that exhibits excellent electrocatalytic activity and durability on the metal sulfides in overall water splitting. [ABSTRACT FROM AUTHOR]