A facile route for the synthesis of nanostructured oxides and hydroxides of cobalt using laser ablation synthesis in solution (LASIS)

Abstract

We used a pulsed laser ablation synthesis in solution (LASIS) to produce cobalt oxide/hydroxide nanoparticles (NPs) with tailored size, morphology and structure at different laser fluences, wavelengths (532 and 1064 nm) and solvent conditions. Specifically, LASIS on bulk Co in the presence and absence of O2 in an aqueous solution initially produces cobalt monoxide (CoO) and single crystal β-cobalt hydroxide (β-Co(OH)2) nanoparticles (NPs) respectively that finally transform into cobaltosic oxide (Co3O4) through oxidation and/or thermal decomposition. Transmission electron microscopy (TEM) and scanning mobility particle sizer (SMPS) measurements on the final products reveal a bimodal size distribution of agglomerated NPs (for the 1064 and 532 nm laser) at low laser fluences, where the ablation mechanism is dominated by vaporization and normal boiling. In contrast, more efficient and predominant explosive boiling at higher laser fluences produces a mono-modal size distribution of spherically shaped primary NPs in agglomerates. Furthermore, higher absorbance of the 532 nm laser by solution-phase colloidal NPs re-ablates them into spherical shapes of larger size (∼13-22 nm) as compared to the ones from using 1064 nm LASIS (∼10-14 nm), while rendering 532 nm LASIS less productive than 1064 nm LASIS over an extended period of time. Finally, Co3O4 nanorods with enhanced localized surface plasmon resonance (LSPR) are synthesized at high pH (pH ≥ 13) and low laser fluence (<5 mJ cm(-2)) conditions. Such nanostructured materials are promising candidates as photocatalysts or additives in nanocomposite materials with enhanced light absorption properties.

MoS2 nanosheets decorated with ultrafine Co3O4 nanoparticles for high-performance electrochemical capacitors

“…3a) of the initial LALinduced Co colloids and determine that the Co colloid solution actually consists of many hexagonal b-Co(OH) 2 NPs (JCPDS No 74-1057). Due to the present of oxygen, b-Co(OH) 2 is partly oxidized to Co 3 O 4 (JCPDS No 01-1152); and after been aged at 70 C for 3 days, the initial b-Co(OH) 2 completely evolved into a cubic-structured Co 3 O 4 nanocrystalline, which is consistent with other related reports [29,30]. The XRD pattern of pure MoS 2 is presented in Fig.…”

One-step femtosecond laser ablation synthesis of sub-3 nm gold nanoparticles stabilized by silica

“…Recently, the approaches of PLAL and laser photochemical reduction have been combined into a single process through ablation of a solid target either immersed in or subsequently exposed to metal salt solution, in what is termed reactive laser ablation in liquid (RLAL) [10,[45][46][47][48][49][50][51][52]. RLAL has been widely used to generate metal-silica nanostructures, including Si/M (M = Ag, Au, Pd, Pt) core/shell NPs [47], Ag-core/silica-shell NPs [48], and large silica particles decorated with Au or Ag NPs [49].…”

Nonlinear optical properties of metal nanoparticles: a review

“…15 In the past two decades, efficient nonlinear optical materials have made signicant progress in laser technology, and these materials have large nonlinear optical properties and a fast nonlinear response for various photonic and optoelectronic applications such as laser ablation, pulsed laser deposition, optical communication, optical information processing, and optical data storage and as optical limiters. [16][17][18][19][20][21] Optical limiting is one of the most promising practical applications of all nonlinear optical properties and can be used to protect the human eye and photosensitive components of delicate optical instruments from damage caused by intense optical radiation. 22 Optical limiters strongly attenuate a potentially dangerous laser beam while exhibiting a transmittance to low ambient light.…”