Wind turbine performance can be significantly reduced when the surface integrity of the turbine blades is compromised. Many frontier high-energy regions that are sought for wind farm development ...including Nordic, warm-humid, and desert-like environments often provide conditions detrimental to the surface of the turbine blade. In Nordic climates ice can form on the blades and the turbine structure itself through a variety of mechanisms. Initial ice adhesion may slightly modify the original aerodynamic profile of the blade; continued ice accretion can drastically affect the structural loading of the entire rotor leading to potentially dangerous situations. In warmer climates, a humid wind is desirable for its increased density; however, it can come at a price when the region supports large populations of insects. Insect collisions with the blades can foul blade surfaces leading to a marked increase in skin drag, reducing power production by as much as 50%. Finally, in more arid regions where there is no threat from ice or insects, high winds can carry soil particles eroded from the ground (abrasive particles). Particulate-laden winds effectively sand-blast the blade surfaces, and disrupt the original skin profile of the blade, again reducing its aerodynamic efficiency. While these problems are challenging, some mitigative measures presently exist and are discussed in the paper. Though, many of the current solutions to ice or insect fouling actually siphon power from the turbine itself to operate, or require that the turbine be stopped, in either case, profitability is diminished. Our survey of this topic in the course of our research suggests that a desirable solution may be a single surface engineered coating that reduces the incidence of ice adhesion, insect fouling, and protects the blade surface from erosive deterioration. Research directions that may lead to such a development are discussed herein.
All-inorganic perovskites nanostructures, such as CsPbCl3 nanocrystals (NCs), are promising in many applications including light-emitting diodes, photovoltaics, and photodetectors. Despite the ...impressive performance that was demonstrated, a critical issue remains due to the instability of the perovskites in ambient. Herein, we report a method of passivating crystalline CsPbCl3 NC surfaces with 3-mercaptopropionic acid (MPA), and superior ambient stability is achieved. The printing of these colloidal NCs on the channel of graphene field-effect transistors (GFETs) on solid Si/SiO2 and flexible polyethylene terephthalate substrates was carried out to obtain CsPbCl3 NCs/GFET heterojunction photodetectors for flexible and visible-blind ultraviolet detection at wavelength below 400 nm. Besides ambient stability, the additional benefits of passivating surface charge trapping by the defects on CsPbCl3 NCs and facilitating high-efficiency charge transfer between the CsPbCl3 NCs and graphene were provided by MPA. Extraordinary optoelectronic performance was obtained on the CsPbCl3 NCs/graphene devices including a high ultraviolet responsivity exceeding 106 A/W, a high detectivity of 2 × 1013 Jones, a fast photoresponse time of 0.3 s, and ambient stability with less than 10% degradation of photoresponse after 2400 h. This result demonstrates the crucial importance of the perovskite NC surface passivation not only to the performance but also to the stability of the perovskite optoelectronic devices.
Securing an affordable and environmentally friendly fuel source is a pressing global need. Hydrogen gas, renowned for being carbon-free and derived from water, stands as an abundant and low-cost ...energy resource. Efficient water electrolysis hinges upon selecting economical yet effective electrocatalysts. In this context, copper-based chalcogenides have garnered attention for driving water electrolysis. This report presents a newly developed electrocatalyst: copper sulfide (CuS) supported silver indium selenide-nickel foam (AgInSe2–NF) composites, characterized by a diverse array of morphologies. The optimized CuS@15%AgInS2 electrocatalyst showcased superior performance when related to electrocatalysts based on noble metals and metal sulfides which were reported previously. CuS@15%AgInSe2–NF nanocomposite exhibits significant potential in water oxidation, revealing a marked reduction in overpotential: 289 mV at a benchmark current density of 10 mA cm−2 for OER and 85 mV for HER. This heightened efficiency is accredited to various exceptional elements associated with design of nanocomposite, which offers abundant reactive sites and ion transfer pathways within its structure. Furthermore, this design fortifies structural integrity and conductivity of CuS@15%AgInSe2 heterostructure. Additionally, synergistic interplay between AgInSe2 and CuS enhances electron transport and augments electrocatalytic properties. Notably, electrocatalyst exhibits exceptional stability, consistently producing hydrogen gas for over 25 h. These findings not only highlight potential of CuS@15%AgInSe2 for a multitude of OER and HER applications but also underscore effectiveness of material hybridization as a straightforward yet potent method to enhance the electrochemical performance of an electrode.
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Metasurfaces consisting of electrically thin and densely packed planar arrays of subwavelength elements enable an unprecedented control of the impinging electromagnetic fields. Spatially modulated ...metasurfaces can efficiently tailor the spatial distribution of these fields with great flexibility. Similarly, time-modulated metasurfaces can be successfully used to manipulate the frequency content and time variations in the impinging field. In this article, we present time-modulated reflective metasurfaces that cause a frequency shift to the impinging radiation, thus realizing an artificial Doppler effect in a nonmoving electrically thin structure. Starting from the theoretical analysis, we analytically derive the required time modulation of the surface admittance to achieve this effect and present a realistic time-varying structure, based on a properly designed and dynamically tuned high-impedance surface. It is analytically and numerically demonstrated that the field emerging from the metasurface is up-/down-converted in frequency according to the modulation profile of the metasurface. The proposed metasurface concept, enabling a frequency modulation of the electromagnetic field "on-the-fly," may find application in telecommunication, radar, and sensing scenarios.
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•A surface engineering method is proposed to boost the performance of flexible carbon.•Adding arginine during the activation can produce a micro-graphitized carbon layer.•This thin ...carbon layer can improve conductivity and reduce charge transfer resistance.•The resultant flexible carbon shows a high capacitance of 403 C·g−1 or 2583 mC·cm−2.
The relatively low specific capacitance of flexible carbons hinders their practical application for fabricating high-performance flexible supercapacitors. In this work, a surface engineering method is proposed to boost the supercapacitive performance of the flexible carbon. In this method, a flexible carbon was fabricated from carbon felt via co-activation with potassium argininate and potassium hydroxide (KOH) as activators, and the resulting material is abbreviated as AKCF. Unlike traditional KOH activation processes, the addition of potassium argininate can produce a micro-graphitized carbon layer to be the outer layer of AKCF fibers for achieving better electronic transfer. Due to the improved conductivity and lower charge transfer resistance endowed by a thin micro-graphitized carbon layer, the capacitance of the AKCF-0.1 (0.1 M arginine was used) electrode obtained by the co-activation process is elevated to a 1.8-fold higher value of 403 C·g−1 (2583 mC·cm−2) relative to the AKCF-0 (0 M arginine was used) electrode prepared by KOH activation alone (222 C·g−1 or 1369 mC·cm−2). Moreover, this AKCF-0.1 electrode also displays satisfactory rate capability (66% capacitance retention after a 20-fold current increase) and highly stable cycling performance (no capacitance decline after 20,000 cycles). In addition, the asymmetric supercapacitors constructed with this AKCF-0.1 electrode as the flexible negative electrode expresses high energy densities of 68.4 Wh·kg−1 and 0.139 mWh·cm−2 in aqueous and gel electrolytes, respectively.
We make a critical review on the recent reported surface strategies of g-C3N4 toward enhancing water splitting performance, focusing on the theoretical basic and strategy-activity correlation.
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•The basic of photocatalytic water splitting is presented.•The advanced surface strategies are classified and discussed.•The recent progress of surface strategies on g-C3N4 for water splitting is reviewed.•A brief conclusion is given and the remaining challenges for artificial photosynthesis are outlooked.
Photocatalytic water splitting based on particulate photocatalysts offers a scalable pathway to generate hydrogen fuels while also mitigating environmental crisis. To establish high-efficiency photocatalytic system, strategies based on the modification of the host photocatalyst surface hold the key to affect the adsorption/activation ability of reaction molecules, and the efficiency of charge transport. As one type of layered conjugated polymer materials, graphitic carbon nitride (g-C3N4) has recently attracted extensive scientific interest in this research area owing to its unique structure and fascinating properties. However, the efficient water splitting is still far from easy over g-C3N4. Encouragingly, the surface strategies to modify g-C3N4 play an important role in tuning the surface properties resulted in improved performance. The summary, classification and mechanism understanding of surface strategies on g-C3N4 is of great significance. In this review, we firstly summarize the basic of photocatalytic water splitting. Then, three common strategies for improving the photocatalytic water splitting efficiency of g-C3N4 are classified in surface regulation, functionalization and assembly. As a focus, recent advances of surface strategies on g-C3N4 are discussed in detail combined with some previous studies, emphasizing the inner correlation between improved photocatalytic performance and corresponding surface strategy. Finally, a brief conclusion and the remaining challenges for artificial photosynthesis are presented. This review highlights the crucial role of the surface structure tailoring and provides ideas for designing highly efficient photocatalysts toward water splitting by surface strategies.
The photo-generated charge carriers dynamic of SrTiO3/Ti3C2 MXene Schottky junction is effectively improved by surface and interface engineering.
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•A Schottky heterojunction of ...SrTiO3/Ti3C2 MXene is constructed.•The synthesis method adopted the green simple softening method.•The tightly binding interface and Ti vacancy are constructed in situ growth.•The migration of photogenerated carriers is promoted by interface engineering.•The introduction of Ti vacancy increases the active site of hydrogen evolution.
Surface and interface engineering of composite photocatalysts are effective ways to enhance the dynamics of photo-generated charge carriers. In this work, SrTiO3/Ti3C2 MXene (STO/TC) Schottky heterojunction is constructed by in-situ growth of SrTiO3 (STO) on Ti3C2 MXene (TC) through Sr(OH)2 etching the surfaces of TC. This in-situ growth strategy not only creates the tight chemically bonded interfaces by SrTiO3 nanoparticles uniformly anchoring on the surface of two-dimensional Ti3C2 MXene nanosheets for promoting the photo-generated charge carrier separation, but also introduces surface Ti vacancies as the efficient catalytic active sites to accelerate the charge carrier transfer process for efficient hydrogen production. The photocatalytic system constructed by interface and surface engineering optimizes the photo-generated charge carrier dynamics and refines the photocatalytic hydrogen evolution performance (6.8 times higher than pristine SrTiO3) and stability. This work is expected to provide an alternative strategy to construct highly efficient photocatalysts with hydrogen evolution.
Decades of intense scientific research investigations clearly suggest that only a subset of a large number of metals, ceramics, polymers, composites, and nanomaterials are suitable as biomaterials ...for a growing number of biomedical devices and biomedical uses. However, biomaterials are prone to microbial infection due to
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), hepatitis, tuberculosis, human immunodeficiency virus (HIV), and many more. Hence, a range of surface engineering strategies are devised in order to achieve desired biocompatibility and antimicrobial performance in situ. Surface engineering strategies are a group of techniques that alter or modify the surface properties of the material in order to obtain a product with desired functionalities. There are two categories of surface engineering methods: conventional surface engineering methods (such as coating, bioactive coating, plasma spray coating, hydrothermal, lithography, shot peening, and electrophoretic deposition) and emerging surface engineering methods (laser treatment, robot laser treatment, electrospinning, electrospray, additive manufacturing, and radio frequency magnetron sputtering technique). Atomic-scale engineering, such as chemical vapor deposition, atomic layer etching, plasma immersion ion deposition, and atomic layer deposition, is a subsection of emerging technology that has demonstrated improved control and flexibility at finer length scales than compared to the conventional methods. With the advancements in technologies and the demand for even better control of biomaterial surfaces, research efforts in recent years are aimed at the atomic scale and molecular scale while incorporating functional agents in order to elicit optimal in situ performance. The functional agents include synthetic materials (monolithic ZnO, quaternary ammonium salts, silver nano-clusters, titanium dioxide, and graphene) and natural materials (chitosan, totarol, botanical extracts, and nisin). This review highlights the various strategies of surface engineering of biomaterial including their functional mechanism, applications, and shortcomings. Additionally, this review article emphasizes atomic scale engineering of biomaterials for fabricating antimicrobial biomaterials and explores their challenges.
Dye-sensitized solar cell (DSSC) offers an efficient and easily implemented technology for future energy supply. Compared to conventional silicon solar cells, it provides comparable power conversion ...efficiency (PCE) at low material and manufacturing costs. DSSC materials such as titanium oxide (TiO2) are inexpensive, abundant and innocuous to the environment. Since DSSC materials are less prone to contamination and processable at ambient temperature, a roll-to-roll process could be utilized to print DSSCs on the mass production line. DSSCs perform better under lower light intensities, which makes them an excellent choice for indoor applications. Due to the advancement of molecular engineering, colored and transparent thin films have been introduced to enhance the aesthetic values. Up to now, such benefits have attracted considerable research interests and commercialization effort. Here, this review examines advanced techniques and research trends of this promising technology from the perspective of device modeling, state-of-art techniques, and novel device structures.
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The emergence of two-dimensional (2D) transition metal carbides, carbonitrides and nitrides, referred to MXenes, with a general chemical formula of Mn+1XnTx have aroused considerable ...interest and shown remarkable potential applications in diverse fields. The unique ultrathin lamellar structure accompanied with charming electronic, optical, magnetic, mechanical and biological properties make MXenes as a kind of promising alternative biomaterials for versatile biomedical applications, as well as uncovering many new fundamental scientific discoveries. Herein, the current state-of-the-art advances of MXenes-related biomaterials are systematically summarized in this comprehensive review, especially focusing on the synthetic methodologies, design and surface engineering strategies, unique properties, biological effects, and particularly the property-activity-effect relationship of MXenes at the nano-bio interface. Furthermore, the elaborated MXenes for varied biomedical applications, such as biosensors and biodevices, antibacteria, bioimaging, therapeutics, theranostics, tissue engineering and regenerative medicine, are illustrated in detail. Finally, we discuss the current challenges and opportunities for future advancement of MXene-based biomaterials in-depth on the basis of the present situation, aiming to facilitate their early realization of practical biomedical applications.
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