We demonstrate the controlled growth of high aspect ratio anatase TiO2 nanorods by hydrolysis of titanium tetraisopropoxide (TTIP) in oleic acid (OLEA) as surfactant at a temperature as low as 80 °C. Chemical modification of TTIP by OLEA is proven to be a rational strategy to tune the reactivity of the precursor toward water. The most influential factors in shape control of the nanoparticles are investigated by simply manipulating their growth kinetics. The presence of tertiary amines or quaternary ammonium hydroxides as catalysts is essential to promote fast crystallization under mild conditions. The novelty of the present approach relies on the large-scale production of organic-capped TiO2 nanocrystals to which standard processing of colloidal nanocrystals, such as surface ligand exchange, can be applied for the first time. Concentrated colloidal titania dispersions can be prepared for a number of fundamental studies in homogeneous solutions and represent a new source of easily processable oxide materia...

Low-Temperature Synthesis of Soluble and Processable Organic-Capped Anatase TiO2 Nanorods

In recent years, nanocrystals of metal sulfide materials have attracted scientific research interest for renewable energy applications due to the abundant choice of materials with easily tunable electronic, optical, physical and chemical properties. Metal sulfides are semiconducting compounds where sulfur is an anion associated with a metal cation; and the metal ions may be in mono-, bi- or multi-form. The diverse range of available metal sulfide materials offers a unique platform to construct a large number of potential materials that demonstrate exotic chemical, physical and electronic phenomena and novel functional properties and applications. To fully exploit the potential of these fascinating materials, scalable methods for the preparation of low-cost metal sulfides, heterostructures, and hybrids of high quality must be developed. This comprehensive review indicates approaches for the controlled fabrication of metal sulfides and subsequently delivers an overview of recent progress in tuning the chemical, physical, optical and nano- and micro-structural properties of metal sulfide nanocrystals using a range of material fabrication methods. For hydrogen energy production, three major approaches are discussed in detail: electrocatalytic hydrogen generation, powder photocatalytic hydrogen generation and photoelectrochemical water splitting. A variety of strategies such as structural tuning, composition control, doping, hybrid structures, heterostructures, defect control, temperature effects and porosity effects on metal sulfide nanocrystals are discussed and how they are exploited to enhance performance and develop future energy materials. From this literature survey, energy conversion currently relies on a limited range of metal sulfides and their composites, and several metal sulfides are immature in terms of their dissolution, photocorrosion and long-term durability in electrolytes during water splitting. Future research directions for innovative metal sulfides should be closely allied to energy and environmental issues, along with their advanced characterization, and developing new classes of metal sulfide materials with well-defined fabrication methods.

Recent advances in metal sulfides: from controlled fabrication to electrocatalytic, photocatalytic and photoelectrochemical water splitting and beyond

Template-based synthesis of nanorod, nanowire, and nanotube arrays.

The single crystalline CdS nanobelts were synthesized by an improved vapor-liquid-solid (VLS) process Field emission measurements show that the nanostructures have a low turn-on field of 37 V&m-1 at a current density of 10 μA cm-1, a low threshold field of 93 V μm cm-1 and a high enhancement factor of 1298 When assembled into nanoscale visible light photodetectors, the CdS nanobelts showed good sensitivity and wavelength selectivity The results imply that the present CdS nanobelts are excellent candidates for applications in high-performance field emitters and photodetectors

Single-crystalline CdS nanobelts for excellent field-emitters and ultrahigh quantum-efficiency photodetectors.

▪ Abstract This review focuses on the preparation of capped nanoparticles of inorganic materials, classified by composition. The materials described include elemental metals and metalloids (semiconductors), chalcogenide II–VI and IV–VI semiconductors, III–V semiconductors, and oxides (both of simple- and multitransition metal). Although particular emphasis is placed on methods that yield large volumes of nanoparticles, recent novel methods that may not necessarily be scalable are also reviewed. The review makes apparent the richness of chemistry that has become routine to practitioners in the field; diverse inorganic systems with distinct chemistry require distinct methods of preparation.

Synthesis routes for large volumes of nanoparticles

Polymer‐Controlled Growth of CdS Nanowires

A chemical solution transport mechanism for one-dimensional growth of CdS nanowires

Synthesis of Nanocrystalline Cobalt Selenide in Nonaqueous Solvent

Ethanolthermal synthesis to γ-CuI nanocrystals at low temperature

Zinc powder reacts with equivalent elemental selenium in solvent ethylenediamine at 120 °C for 6 h to form a complex, which is converted to ZnSe nanoparticles by pyrolysis or protonization. X-ray diffraction results suggest that the as-formed products have wurtzite structure. Transmission electron microscopy observation show that particles with spherical and laminar morphology were produced by pyrolysis and protonization, respectively. The formation of ZnSe nanoparticles is also investigated by infrared and thermal analysis.

J. H. Zhan

Papers

Polymer‐Controlled Growth of CdS Nanowires

A chemical solution transport mechanism for one-dimensional growth of CdS nanowires

Synthesis of Nanocrystalline Cobalt Selenide in Nonaqueous Solvent

Ethanolthermal synthesis to γ-CuI nanocrystals at low temperature

A solvothermal route to wurtzite ZnSe nanoparticles