Advanced energy conversion and storage (ECS) devices (including fuel cells, photoelectrochemical water splitting cells, solar cells, Li-ion batteries and supercapacitors) are expected to play a major role in the development of sustainable technologies that alleviate the energy and environmental challenges we are currently facing. The successful utilization of ECS devices depends critically on synthesizing new nanomaterials with merits of low cost, high efficiency, and outstanding properties. Recent progress has demonstrated that nanostructured metal chalcogenides (MCs) are very promising candidates for efficient ECS systems based on their unique physical and chemical properties, such as conductivity, mechanical and thermal stability and cyclability. In this review, we aim to provide a summary on the liquid-phase synthesis, modifications, and energy-related applications of nanostructured metal chalcogenide (MC) materials. The liquid-phase syntheses of various MC nanomaterials are primarily categorized with the preparation method (mainly 15 kinds of methods). To obtain optimized, enhanced or even new properties, the nanostructured MC materials can be modified by other functional nanomaterials such as carbon-based materials, noble metals, metal oxides, or MCs themselves. Thus, this review will then be focused on the recent strategies used to realize the modifications of MC nanomaterials. After that, the ECS applications of the MC/modified-MC nanomaterials have been systematically summarized based on a great number of successful cases. Moreover, remarks on the challenges and perspectives for future MC research are proposed (403 references).

Nanostructured metal chalcogenides: synthesis, modification, and applications in energy conversion and storage devices

Photocatalysis is a green technology which converts abundantly available photonic energy into useful chemical energy. With a rapid rise of flow photoreactors in the last decade, the design and development of novel semiconductor photocatalysts is happening at a blistering rate. Currently, developed synthetic approaches have allowed the design of diverse modified/unmodified semiconductor materials exhibiting enhanced performances in heterogeneous photocatalysis. In this review, we have classified the so far reported highly efficient modified/unmodified semiconductor photocatalysts into four different categories based on the elemental composition, band gap engineering and charge carrier migration mechanism in composite photocatalysts. The recent synthetic developments are reported for each novel semiconductor photocatalyst within the four different categories, namely: pure semiconductors, solid solutions, type-II heterojunction nanocomposites and Z-scheme. The motivation behind the synthetic upgrading of modified/unmodified (pure) semiconductor photocatalysts along with their particular photochemical applications and photoreactor systems have been thoroughly reviewed.

/pdf/nanostructured-materials-for-photocatalysis-54b0fo6szc.pdf

Nanostructured materials for photocatalysis

Colloidal heterostructured nanocrystals: Synthesis and growth mechanisms

The special mechanical properties of nanoparticles allow for novel applications in many fields, e.g., surface engineering, tribology and nanomanufacturing/nanofabrication. In this review, the basic physics of the relevant interfacial forces to nanoparticles and the main measuring techniques are briefly introduced first. Then, the theories and important results of the mechanical properties between nanoparticles or the nanoparticles acting on a surface, e.g., hardness, elastic modulus, adhesion and friction, as well as movement laws are surveyed. Afterwards, several of the main applications of nanoparticles as a result of their special mechanical properties, including lubricant additives, nanoparticles in nanomanufacturing and nanoparticle reinforced composite coating, are introduced. A brief summary and the future outlook are also given in the final part. (Some figures may appear in colour only in the online journal)

https://iopscience.iop.org/article/10.1088/0022-3727/47/1/013001/pdf

Mechanical properties of nanoparticles: basics and applications

In the past two decades, the synthetic development of magnetic nanoparticles (NPs) has been intensively explored for both fundamental scientific research and technological applications. Different from the bulk magnet, magnetic NPs exhibit unique magnetism, which enables the tuning of their magnetism by systematic nanoscale engineering. In this review, we first briefly discuss the fundamental features of magnetic NPs. We then summarize the synthesis of various magnetic NPs, including magnetic metal, metallic alloy, metal oxide, and multifunctional NPs. We focus on the organic phase syntheses of magnetic NPs with precise control over their sizes, shapes, compositions, and structures. Finally we discuss the applications of various magnetic NPs in sensitive diagnostics and therapeutics, high-density magnetic data recording and energy storage, as well as in highly efficient catalysis.

Organic Phase Syntheses of Magnetic Nanoparticles and Their Applications.

Maximized specific loss power and intrinsic loss power approaching theoretical limits for alternating-current (AC) magnetic-field heating of nanoparticles are reported. This is achieved by engineering the effective magnetic anisotropy barrier of nanoparticles via alloying of hard and soft ferrites. 22 nm Co0.03 Mn0.28 Fe2.7 O4 /SiO2 nanoparticles reach a specific loss power value of 3417 W g-1metal at a field of 33 kA m-1 and 380 kHz. Biocompatible Zn0.3 Fe2.7 O4 /SiO2 nanoparticles achieve specific loss power of 500 W g-1metal and intrinsic loss power of 26.8 nHm2 kg-1 at field parameters of 7 kA m-1 and 380 kHz, below the clinical safety limit. Magnetic bone cement achieves heating adequate for bone tumor hyperthermia, incorporating an ultralow dosage of just 1 wt% of nanoparticles. In cellular hyperthermia experiments, these nanoparticles demonstrate high cell death rate at low field parameters. Zn0.3 Fe2.7 O4 /SiO2 nanoparticles show cell viabilities above 97% at concentrations up to 500 µg mL-1 within 48 h, suggesting toxicity lower than that of magnetite.

Maximizing Specific Loss Power for Magnetic Hyperthermia by Hard-Soft Mixed Ferrites.

This mini-review summarizes the recent advances in chemical synthesis and assembly of monodisperse magnetic nanoparticles for magnetic applications. After a brief introduction to nanomagnetism, the review focuses on recent developments in solution phase syntheses and assemblies of monodisperse Fe, CoFe, FePt and SmCo5 nanoparticles. The review further outlines the structural and magnetic properties of these nanoparticles for magnetic information and energy storage applications.

Synthesis and assembly of magnetic nanoparticles for information and energy storage applications

Fe(3)Se(4) nanostructures have been synthesized by a one-pot high-temperature organic-solution-phase method. The size of these nanostructures can be tuned from 50 to 500 nm, and their shapes can be varied from nanosheets and nanocacti to nanoplatelets. These nanostructures exhibit hard magnetic properties, with giant coercivity values reaching 40 kOe at 10 K and 4 kOe at room temperature. The estimated magnetocrystalline anisotropy constant is 6 x 10(6) erg cm(-3), comparable to that of hexagonal close-packed cobalt. The magnetic properties can be further tuned by substituting Fe ions by other transition-metal elements such as Co.

Fe3Se4 Nanostructures with Giant Coercivity Synthesized by Solution Chemistry

Mn-doped CdS nanorods synthesized by solution phase chemistry demonstrate robust ferromagnetic properties at and above room temperature. The nanorods show large coercivity, possibly originating from the shape anisotropy. The hysteresis measurements reveal strong temperature dependence. Possible origin of the ferromagnetism is discussed.

http://www.cbe.buffalo.edu/people/pdfPub.jsp?id=749

Room temperature ferromagnetism in Mn-doped CdS nanorods

ZnS, a II-VI semiconductor with a relatively high direct bandgap (approximately 3.6 eV) in the near-UV region, has potential applications in areas such as solar cells, lasers and displays. In addition, ZnS nanoparticles can be applied as phosphors, probes for bioimaging, emitters in light emitting diodes and photocatalysts. Here, we report synthesis of cubic ZnS nanoparticles from a low-cost single-source precursor in a continuous spray pyrolysis reactor. In this approach, the evaporation and decomposition of precursor and nucleation of particles occur sequentially. Product particles were characterized by HRTEM, XRD, and EDX. Particles with diameters ranging from 2 to 7 nm were produced. HF was used to remove ZnO impurities and other surface contamination. As-synthesized ZnS nanoparticles exhibit blue photoluminescence near 440 nm under UV excitation and have quantum yields up to 15% after HF treatment. This demonstrates a potentially general approach for continuous low-cost synthesis of semiconductor quantum dots for applications where tight control of the size distribution is less important than scalable, economical production.

https://iopscience.iop.org/article/10.1088/0957-4484/20/23/235603/pdf

Hongwang Zhang

Papers

Maximizing Specific Loss Power for Magnetic Hyperthermia by Hard-Soft Mixed Ferrites.

Synthesis and assembly of magnetic nanoparticles for information and energy storage applications

Fe3Se4 Nanostructures with Giant Coercivity Synthesized by Solution Chemistry

Room temperature ferromagnetism in Mn-doped CdS nanorods

Spray pyrolysis synthesis of ZnS nanoparticles from a single-source precursor