Minhua Cao

Bio: Minhua Cao is an academic researcher from Beijing Institute of Technology. The author has contributed to research in topics: Lithium & Anode. The author has an hindex of 56, co-authored 173 publications receiving 9331 citations. Previous affiliations of Minhua Cao include Northeast Normal University & Beijing University of Chemical Technology.

Hierarchical Dendrite-Like Magnetic Materials of Fe3O4, γ-Fe2O3, and Fe with High Performance of Microwave Absorption

Abstract: Iron-based microstructured or nanostructured materials, including Fe, γ-Fe2O3, and Fe3O4, are highly desirable for magnetic applications because of their high magnetization and a wide range of magnetic anisotropy. An important application of these materials is use as an electromagnetic wave absorber to absorb radar waves in the centimeter wave (2−18 GHz). Dendrite-like microstructures were achieved with the phase transformation from dendritic α-Fe2O3 to Fe3O4, Fe by partial and full reduction, and γ-Fe2O3 by a reduction−oxidation process, while still preserving the dendritic morphology. The investigation of the magnetic properties and microwave absorbability reveals that the three hierarchical microstructures are typical ferromagnets and exhibit excellent microwave absorbability. In addition, this also confirms that the microwave absorption properties are ascribed to the dielectric loss for Fe and the combination of dielectric loss and magnetic loss for Fe3O4 and γ-Fe2O3.

Fe3O4–Graphene Nanocomposites with Improved Lithium Storage and Magnetism Properties

Abstract: In this paper, we proposed a facile one-step strategy to prepare graphene-Fe3O4 (GN–Fe3O4) nanocomposites under hydrothermal conditions, where the reduction process of graphite oxide (GO) sheets into GN was accompanied by the generation of Fe3O4 nanoparticles. The reduction extent of GO by this process could be comparable to that by conventional methods. A transmission electron microscopy image has shown that the as-formed Fe3O4 nanoparticles with a diameter as small as 7 nm were densely and uniformly deposited on GN sheets, and, as a result, the aggregating of the Fe3O4 nanoparticles was effectively prevented. The GN–Fe3O4 nanocomposites exhibit improved cycling stability and rate performances as a potential anode material for high-performance lithium ion batteries. In addition, the GN–Fe3O4 nanocomposites exhibit a superparamagnetic behavior, making them promising candidates for practical applications in the fields of bionanotechnology/controlled targeted drug delivery.

Co9S8@MoS2 Core-Shell Heterostructures as Trifunctional Electrocatalysts for Overall Water Splitting and Zn-Air Batteries.

Abstract: The development of efficient non-noble-metal electrocatalysts is of critical importance for clean energy conversion systems, such as fuel cells, metal–air batteries, and water electrolysis. Herein, uniform Co9S8@MoS2 core–shell heterostructures have been successfully prepared via a solvothermal approach, followed by an annealing treatment. Transmission electron microscopy, X-ray absorption near-edge structure, and X-ray photoelectron spectroscopy measurements reveal that the core–shell structure of Co9S8@MoS2 can introduce heterogeneous nanointerface between Co9S8 and MoS2, which can deeply influence its charge state to boost the electrocatalytic performances. Besides, due to the core–shell structure that can promote the synergistic effect of Co9S8 and MoS2 and provide abundant catalytically active sites, Co9S8@MoS2 exhibits a superior hydrogen evolution reaction performance with a small overpotential of 143 mV at 10 mA cm–2 and a small Tafel slope value of 117 mV dec–1 under alkaline solution. Meanwhile,...

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Abstract: Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Noncovalent Functionalization of Graphene and Graphene Oxide for Energy Materials, Biosensing, Catalytic, and Biomedical Applications

Abstract: This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of π–π interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graph...