A facile coordination compound precursor route to controlled synthesis of Co3O4 nanostructures and their room-temperature gas sensing properties

Geng, Baoyou; Zhan, F. Benjamin; Fang, Caihong; Ye, Nan

doi:10.1039/b805378b

Cited by 121 publications

(74 citation statements)

References 52 publications

(25 reference statements)

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“…500 nm aggregates of clustered 20 nm × 20 nm hexagonal nanocrystals, although certain conditions yield isolated 120 nm × 120 nm hexagonal nanocrystals. 14,20 Chelate(EDTA)-and sonication-assisted syntheses produce even larger Co(O)OH aggregates. 24,25 Spatially constrained or "caged" syntheses have been performed using Ferritin as a template to control particle size.…”

Section: −23mentioning

confidence: 99%

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Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

et al. 2012

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Photochemical methods facilitate the generation, isolation, and study of metastable nanomaterials having unusual size, composition, and morphology. These harder-to-isolate and highly reactive phases, inaccessible using conventional high-temperature pyrolysis, are likely to possess enhanced and unprecedented chemical, electromagnetic, and catalytic properties. We report a fast, low-temperature and scalable photochemical route to synthesize very small (~3 nm) monodisperse cobalt oxyhydroxide (Co(O)OH) nanocrystals. This method uses readily and commercially available pentaamminechlorocobalt(III) chloride, [Co(NH 3 ) 5 Cl]Cl 2 , under acidic or neutral pH and proceeds under either near-UV (350 nm) or Vis (575 nm) illumination. Control experiments showed that the reaction proceeds at competent rates only in the presence of light, does not involve a free radical mechanism, is insensitive to O 2, and proceeds in two steps: (1) Aquation of [Co(NH 3 ) 5 Cl] 2+ to yield [Co(NH 3 ) 5 (H 2 O)] 3+ , followed by (2) slow photoinduced release of NH 3 from the aqua complex. This reaction is slow enough for Co(O)OH to form but fast enough so that nanocrystals are small (ca. 3 nm). The alternative dark thermal reaction proceeds much more slowly and produces much larger (~250 nm) polydisperse Co(O)OH aggregates. UV-Vis absorption measurements and ab initio calculations yield a Co(O)OH band gap of 1.7 eV. Fast thermal annealing of Co(O)OH nanocrystals leads to Co 3 O 4 nanocrystals with overall retention of nanoparticle size and morphology. Thermogravimetric analysis shows that oxyhydroxide to mixed-oxide phase transition occurs at significantly lower temperatures (up to T = 64 degrees C) for small nanocrystals compared with the bulk. KeywordsAb initio calculations, Aqua complexes, Catalytic properties, control experiments, fast thermal annealing, free radical mechanism, high-temperature pyrolysis, low temperatures, monodisperse, nanoparticle sizes, neutral pH, Oxyhydroxides, Pentaamminechlorocobalt, Photochemical method, thermal synthesis, chlorine compounds, cobalt, cracking (chemical) Disciplines Chemistry CommentsReprinted (adapted) with permission from Journal of Physical Chemistry C 116 (2012)

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Section: −23mentioning

confidence: 99%

“…14,20 They tend to produce large ca. 500 nm aggregates of clustered 20 nm × 20 nm hexagonal nanocrystals, although certain conditions yield isolated 120 nm × 120 nm hexagonal nanocrystals.…”

Section: −23mentioning

confidence: 99%

Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

et al. 2012

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“…77, 78 Co 3 O 4 octahedra ( Figure 10.2d) consisting of {111} planes have also been synthesized by thermal decomposition of cobalt complexes with proper procedures that favor a fast-growing rate along the [111] direction but a slow-growing rate along the [100] direction. 79,80 …”

Section: Co 3 O 4 -Nps and Cubesmentioning

confidence: 99%

“…122 Occasionally, CoOOH and Co alkoxide were also used as the precursors to prepare Co 3 O 4 nanosheets or nanoplates. 80,123 However, almost all Co 3 O 4 nanosheets possessed porous structures or cracks because of the poor morphological stability of the precursors (Figure 10.4c-f). 80 In addition to the low-dimensional nanocrystals with tailored geometries, the subsequent utilization of these nanostructures as building blocks to construct hierarchical structures is promising.…”

Section: Multidimensional Co 3 O 4 Nanostructuresmentioning

confidence: 99%

Tuning the Morphology of Metal Oxides for Catalytic Applications

Shen

2013

Nanocatalysis Synthesis and Applications

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“…Co 3 O 4 exhibited potential application in a wide variety of fields, such as battery materials [9][10][11], catalysis [12,13], and magnetic materials [4,8,14]. It is now commonly known that the properties of nanomaterials strongly depend on the shape of particles, which is a dominating factor to their ultimate performance and applications [8,[15][16][17][18]. In this paper, a hydrothermal pathway was carried out to investigate the controlled formation of 1D Co 3 O 4 .…”

Section: Introductionmentioning

confidence: 99%

Morphology dependence on anions in hydrothermal synthesis of Co3O4

2013

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One-dimensional (1D) nanostructures of Co 3 O 4 were synthesized via a mild hydrothermal route. The results of XRD, IR, and TEM revealed a phase transformation was accompanied by the replacement of NO 3 − with CO 3 2− throughout the hydrothermal process. The symmetric types and amount of NO 3 − and CO 3 2− intercalated between the brucite layers played an important role in the formation of nanowires from the hydrothermal system. The amount of CO 3 2− increased as the hydrothermal reaction proceeded. The substitution of CO 3 2− for NO 3 − led to a variation of interlayer forces thus resulted in the instability of intralayer interactions. Therefore, a shape transformation from sheets to wires occurred. Upon calcination, the shapes of precursors were preserved, and 1D nanostructures of Co 3 O 4 resulted.

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A facile coordination compound precursor route to controlled synthesis of Co3O4 nanostructures and their room-temperature gas sensing properties

Cited by 121 publications

References 52 publications

Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

Tuning the Morphology of Metal Oxides for Catalytic Applications

Morphology dependence on anions in hydrothermal synthesis of Co3O4

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