Single-atom catalytic growth of crystals using graphene as a case study

Anchored Single-atom catalysts have emerged as a cutting-edge research field holding tremendous appeal for applications in the fields of chemicals, energy and the environment. However, single-atom-catalysts for crystal growth is a nascent field. Of the few studies available, all of them are based on state-of-the-art in situ microscopy investigations and computational studies, and they all look at the growth of monolayer graphene from a single-atom catalyst. Despite the limited number of studies, they do, collectively, represent a new sub-field of single-atom catalysis, namely single-atom catalytic growth of crystalline solids. In this review, we examine them on substrate-supported and as freestanding graphene fabrication, as well as rolled-up graphene, viz., single-walled carbon nanotubes (SWCNT), grown from a single atom. We also briefly discuss the catalytic etching of graphene and SWCNT’s and conclude by outlining the future directions we envision this nascent field to take.

Laser Assisted Catalytic Growth of Silicon Nanowires Using Gold and Nickel Catalysts

Laser assisted synthesis of silicon nanowires (SiNWs) was successfully achieved through the use of gold and nickel as catalysts. The diameter of the resulting SiNWs was found to be dependent on that of the catalyst in the case of gold catalyst. The gold catalysed silicon nanowires were unevenly curved and branched owing to the high kinetic energy possessed by gold nanoparticles (AuNPs) at relatively high processing temperature. The use of nickel as catalyst resulted in the formation of several SiNWs on a single nickel catalyst crystallite due to interconnection of the nickel metal crystallites at processing temperature. The morphology of SiNWs catalysed by both nickel and gold was controlled by optimising the laser energy during ablation.

Self-catalytic growth of one-dimensional materials within dislocations in gold

Dislocations in metals affect their properties on the macro- and the microscales. For example, they increase a metal’s hardness and strength. Dislocation outcrops exist on the surfaces of such metals, and atoms in the proximity of these outcrops are more loosely bonded, facilitating local chemical corrosion and reactivity. In this study, we present a unique autocatalytic mechanism by which a system of inorganic semiconducting gold(I) cyanide nanowires forms within preexisting dislocation lines in a plastically deformed Au-Ag alloy. The formation occurs during the classical selective dealloying process that forms nanoporous Au. Nucleation of the nanowire originates at the surfaces of the catalytic dislocation outcrops. The nanowires are single crystals that spontaneously undergo layer-by-layer one-dimensional growth. The continuous growth of nanowires is achieved when the dislocation density exceeds a critical value evaluated on the basis of a kinetic model that we developed.

Liquid-phase catalytic growth of graphene

Ability to mass produce graphene at low cost is of paramount importance in bringing graphene based technologies into market. Here we report a facile liquid-phase catalytic growth of graphene suitable for mass production. Iodine tincture is used to catalyze graphene quantum dots to form graphene films at room temperature. Such method has many advantages, such as environment friendly, high yield, low cost and wide choice of substrates. Furthermore, bandgap of the graphene films is tunable by post-annealing. A photodetector based on the graphene films was developed and could response to a broad wavelength between 365 and 1200 nm. It exhibited detectivity and responsivity of up to 1.1x1013 cmHz1/2W-1 and 81.3 mAW-1 respectively. Hence, the graphene films demonstrated significant applications in the field of optoelectronics. Interestingly, surface of the graphene film prepared by this method has wrinkles that can also be explored for energy storage applications.

An SiOx anode strengthened by the self-catalytic growth of carbon nanotubes

A close-knit CNTs coating that in-situ grown on the SiOx particles realizes the “soft-combination” between SiOx and CNTs, thus conquering the long-lasting issues of poor conductivity and large volume change of SiOx faced.

Liquid-phase catalytic growth of graphene

Ability to mass produce graphene at low cost is of paramount importance in bringing graphene based technologies into market. Here we report a facile liquid-phase catalytic growth of graphene suitable...

Mechanism of Morphology Variations in Colloidal CuGaS2 Nanorods

Cu2-XS nanocrystals can serve as templates and intermediates in the synthesis of a wide range nanocrystals through seeded growth, cation exchange, and/or catalytic growth. This versatility can facilitate and accelerate...