Chiral Nanoceramics Fan, Jinchen; Kotov, Nicholas A.
Advanced materials (Weinheim),
10/2020, Letnik:
32, Številka:
41
Journal Article
Recenzirano
Odprti dostop
The study of different chiral inorganic nanomaterials has been experiencing rapid growth during the past decade, with its primary focus on metals and semiconductors. Ceramic materials can ...substantially expand the range of mechanical, optical, chemical, electrical, magnetic, and biological properties of chiral nanostructures, further stimulating theoretical, synthetic, and applied research in this area. An ever‐expanding toolbox of nanoscale engineering and self‐organization provides a chirality‐based methodology for engineering of hierarchically organized ceramic materials. However, fundamental discoveries and technological translations of chiral nanoceramics have received substantially smaller attention than counterparts from metals and semiconductors. Findings in this research area are scattered over a variety of sources and subfields. Here, the diversity of chemistries, geometries, and properties found in chiral ceramic nanostructures are summarized. They represent a compelling materials platform for realization of chirality transfer through multiple scales that can result in new forms of ceramic materials. Multiscale chiral geometries and the structural versatility of nanoceramics are complemented by their high chiroptical activity, enantioselectivity, catalytic activity, and biocompatibility. Future development in this field is likely to encompass chiral synthesis, biomedical applications, and optical/electronic devices. The implementation of computationally designed chiral nanoceramics for biomimetic catalysts and quantum information devices may also be expected.
Chiral nanoceramics are emerging as a remarkably active area of chiral research. It is still in its infant stage and is thus full of challenges and opportunities. Recent advances in the diversity of chemistries, geometries, and properties of chiral ceramic nanostructures are reviewed. An outlook of synthesis, computational methods, and emerging applications of chiral nanoceramics is presented.
Artificial photosynthesis via photocatalytic CO2 reduction to transform CO2 into C1/C2 hydrocarbon fuels represents a fundamental solution to energy shortage and global warming. This review ...summarizes the recent advances in the development of MXene-based composites for CO2 photoreduction, particularly the effect of MXene surface terminations on their electronic structure and CO2 photoreduction activity, along with a discussion on the major challenges and opportunities in this emerging field.
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•MXenes act as cocatalyst for CO2 photoreduction into C1/C2 hydrocarbon fuels.•High CO2 reduction efficiency is achieved by introducing the MXenes.•The surface terminations of MXenes can affect their electron structure and catalytic activity.•Improved charge separation efficiency and CO2 adsorption/activation ability result in enhanced performance.
Artificial photosynthesis via photocatalytic CO2 reduction to transform CO2 into C1/C2 hydrocarbon fuels represents a fundamental solution to energy shortage and global warming. The main challenges in this process are the low CO2 adsorption and activation stability and low utilization rate of the charge carriers. Two-dimensional transition metal carbides (MXenes) have been explored as cocatalysts to improve the charge separation efficiency and CO2 adsorption/activation power and thereby increase the photocatalytic CO2 reduction activity. In this study, we identify the role of MXenes in heterojunction photocatalytic CO2 reduction and provide some suggestions for preparing MXene-based heterojunction photocatalysts. First, we elaborate on the effect of surface terminations on the electronic structure of MXenes, such as the bandgap and work function. Subsequently, we provide a detailed discussion on the role of MXenes in photocatalytic CO2 reduction: they can serve as electron/hole reservoirs, provide abundant CO2 adsorption and activation sites, and exhibit photothermal conversion characteristics. Moreover, we expound on the photocatalytic CO2 reduction pathways on MXene heterojunction photocatalysts. Finally, the challenges and prospects of MXenes for photocatalytic CO2 reduction are discussed.
Layer-by-layer (LbL) assembly is a widely used tool for engineering materials and coatings. In this Perspective, dedicated to the memory of ACS Nano associate editor Prof. Dr. Helmuth Möhwald, we ...discuss the developments and applications that are to come in LbL assembly, focusing on coatings, bulk materials, membranes, nanocomposites, and delivery vehicles.
Increasing demand and waste of lithium-ion batteries (LIBs) has adversely affected resources and the environment. Multistage utilization of spent LIBs is essential to their sustainable development. ...Here, we propose a simple recycling method of LiCoO2 cathode scrap, based on the first use of the cathode scrap as a catalyst to degrade organic pollutants via peroxymonosulfate activation, and subsequent recovery of valuable metals from the used catalyst. Compared with pristine LiCoO2, the LiCoO2 cathode scrap exhibits excellent catalytic performance due to the active sites generated, such as the vacancy generation and electronic structure modulation by the degradation of LiCoO2 during the continuous lithiation and delithiation processes. The removal efficiency of cathode scrap to the o-phenylphenol exceeds 98% within 60 min, and the degradation efficiency is still above 95% after the 10th use because its unique sandwich and porous structure ensure the stability and recyclability. After multiple catalytic reactions, due to the generation of crack, the separation of the sandwich structure, and further degradation of active materials, the leaching efficiency of transition metals from the cathode scrap in deep eutectic solvent is promoted. 86% of lithium and 95% of cobalt are leached from the used catalyst respectively. This study provides a promising strategy for the sustainable development of LIBs and promotes the utilization of spent LIBs in multiaspect.
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•A simple and green process to recycle spent lithium-ion batteries was proposed.•LiCoO2 cathode scrap was utilized as a catalyst to activate peroxymonosulfate.•The removal efficiency of o-phenylphenol exceeds 98% within 60 min.•A deep eutectic solvent was used to recover transition metals from cathode scrap.•The leaching efficiency of lithium and cobalt are 86% and 95% respectively.
Mechanoelectrical energy conversion is a potential solution for the power supply of miniaturized wearable and implantable systems; yet it remains challenging due to limited current output when ...exploiting low-frequency motions with soft devices. We report a design of a hydrogel generator with mechanoionic current generation amplified by orders of magnitudes with engineered structural and chemical asymmetry. Under compressive loading, relief structures in the hydrogel intensify net ion fluxes induced by deformation gradient, which synergize with asymmetric ion adsorption characteristics of the electrodes and distinct diffusivity of cations and anions in the hydrogel matrix. This engineered mechanoionic process can yield 4 mA (5.5 A m
) of peak current under cyclic compression of 80 kPa applied at 0.1 Hz, with the transferred charge reaching up to 916 mC m
per cycle. The high current output of this miniaturized hydrogel generator is beneficial for the powering of wearable devices, as exemplified by a controlled drug-releasing system for wound healing. The demonstrated mechanisms for amplifying mechanoionic effect will enable further designs for a variety of self-powered biomedical systems.
Multiwalled carbon nanotubes (MWCNTs) have been widely used as reinforcement fillers in past decades. However, the reinforcement effect has been greatly hindered by the limited available interface ...area (AIA) with polymer matrices for polymer composites. Successively, the method of oxidative unzipping MWCNTs into graphene nanoribbons (GNRs) was demonstrated to be the effective way for addressing the inherent drawback of MWCNTs. However, the GNRs are easy to agglomerate in polymer matrix even at relatively low loading amount. In this paper, we found that the functionalization of GNRs with Kevlar® can significantly improve the dispersion state of GNRs in polymer matrix. Consequently, Kevlar®-functionalized graphene nanoribbons (KGNRs) were successfully prepared through non-covalent functionalization of π–π stacking interaction between the aromatic area of Kevlar® and the graphitic surface of GNRs. As-prepared KGNRs were characterized by FT-IR, TGA, XRD and TEM measurements. Poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) were selected as model polymers to investigate the reinforcement effect of KGNRs. The KGNRs could be well dispersed in PVC and PMMA matrices at relatively high loading level. Meantime, the ultimate tensile strengths and Young's modulus of KGNRs/PVC and KGNRs/PMMA composite films were significantly improved. Based on the observations above, KGNRs hold great promise in many potential applications in the future.
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Patients with diabetic foot ulcers usually suffer from inefficient epithelisation and angiogenesis accompanied by chronic wound healing. Diabetic foot ulcers remain a major challenge in clinical ...medicine; however, traditional treatments are incapable of transdermal drug delivery, resulting in a low drug delivery rate. We report the development of Ti
C
MXenes-integrated poly-γ-glutamic acid (γ-PGA) hydrogel microneedles to release asiaticoside (MN-MXenes-AS). Asiaticoside was loaded into PGA-MXenes hydrogel to facilitate cell proliferation while regulating angiogenesis. The characterisation and mechanical strength of the microneedles were investigated in vitro, and the wound-healing efficacy of the microneedles was confirmed in diabetic mice. MXenes significantly improved the mechanical strength of microneedles, while γ-PGA hydrogels provided a moist microenvironment for wound healing. Mice treated with MN-MXenes-AS demonstrated obvious improvements in wound healing process. We successfully fabricated an MXenes-integrated microneedle that possesses sufficient rigidity to penetrate the cuticle for subcutaneous drug delivery, thereby accelerating diabetic wound healing. We demonstrated that MN-MXenes-AS is effective in promoting growth both in vivo and in vitro. Collectively, our data show that MN-MXenes-AS accelerated the healing of diabetic foot ulcers, supporting the use of these microneedles in the treatment of chronic wounds.
Metal nitrogen-carbon catalysts have become a promising alternative to platinum-based catalysts in fuel cells due to their high stability and platinum-like activity. However, the corrosion and ...deactivation of active sites in the solution still restrict the inherent reaction kinetic rate. For this reason, it is important to stabilize the catalyst through a controllable doping strategy to obtain high activity catalysts for oxygen reduction reactions (ORR). Herein, the pyrolysis strategy is demonstrated in the synthesis of iron-based catalysts co-doped with nitrogen and biomass-derived phosphorus (denoted as N, P-Fe/C), and the pore size of the catalyst is mostly distributed at 1 nm or 50 nm, respectively. The half-wave potential (0.893 V) and the current density (4.05 mA cm
−2
) at 0.85 V of the catalyst exceed those of the commercial Pt/C. The remarkable ORR performance can be attributed to its distinct hierarchical pore structure, the modulation effect of nitrogen and phosphorus co-doping on the carbon matrix, and the combined effect of the FeN
x
active sites, which improves the accessibility of reactants and accelerating the absorption/desorption of the reaction intermediate, thereby increasing reaction rates. And N, P-Fe/C has great potential as a promising substitute for platinum-based catalysts.
Chemically-modified gum arabic with glycidyl methacrylate was used for liquid-phase direct exfoliation of graphite. Using this technique, glycidyl methacrylate-modified gum arabic-functionalized ...graphene flakes can be easily obtained by centrifugal separation after sonication. It was demonstrated by transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy and thermogravimetric analysis. The functionalized graphene flakes, coupled with vinyl groups coming from the glycidyl methacrylate-modified gum arabic, were introduced into a poly (acrylic acid) hydrogel to improve its mechanical property. Compared to poly (acrylic acid) hydrogel, the compressive strength and elastic modulus of the graphene/poly (acrylic acid) composite hydrogel with 5 wt% of functionalized graphene flakes reach ∼49.2 and ∼66.9 kPa, increased by ∼846.1% and ∼243.7%, respectively.
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The alignment is a key factor to fully exploit the potential of graphene in reinforcement of polymer composites. However, it is still a challenge to orientate graphene in thermosets because of the ...insoluble and infusible features of the later. In this paper, we report a facile and scalable hot press method to fabricate aligned graphene nanoplate (GnP)/epoxy composites by utilizing the dynamic character of epoxy vitrimer. The bond exchange and topological rearrangement associated viscous flow of epoxy vitrimer during hot press allows the spontaneous orientation of GnP in matrix because the 2D structure and volume exclusion effect. SEM images demonstrate the orientation of GnP, while tensile test reveals the significantly increased reinforcement effect of GnP on matrix after hot press. Moreover, the dynamic reaction of epoxy vitrimer confers good healability and recyclability to the aligned composites as confirmed by the nearly fully recovered mechanical properties of the healed sample after cutting, and the recycled sample after grinding. This work is expected to provide new opportunity for fabrication of aligned thermosetting composites.
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