Table 1 Reaction parameters for CNT yield optimization using AD method

Fe

CH₄

Ar

10 and 40

200

• SWCNTs of 1 nm in diameter are obtained

[86]

Co, Fe, Ni

He

100–500

95–105

• Co helped to produce SWCNTs with uniform diameter of 1.2 nm

[87]

Ni, Pd, Pt

He

550

70

• Ni-filled anode stimulates SWCNT growth

[167]

Ni–Co, Co–Y, Ni–Y

He

660

100

• SWCNT bundle filament is secured. It consists of smaller aligned SWCNTs self-organized into bundle-like crystallites with diameters ranging from 5 to 20 nm

[88]

Y–Ni

He

100–700

40–100

• Only 40% of SWCNTs with diameter 1.3 nm are realized

[168]

Fe

H₂–Ar

200–520

28–34 V

• Highly crystalline SWCNTs with diameter 10–30 nm are obtained

[169]

Co-Ni

He

500

80–100

• SWCNTs are synthesized with uniform diameter 1.7 nm

• SWCNT production rate 7 g/h and the purity 70%

[170]

Ni, Y

Co, He

225

100

• SWCNTs with small diameter 1.66 nm are preferentially etched with the increase of Co concentration

[171]

Fe–Mo

Ar–H₂

225

90

• SWCNTs with selected diameter distributions are secured

[172]

Fe, Co, Ni

He

300

–

• SWCNTs are obtained with a number of carbonaceous and embedded catalyst particles on surface

[110]

Fe

N₂, He, Ar

300–375

60–80

• High-quality SWCNT, DWCNTs, and TWCNT are synthesized with different diameters

• He gas supported SWCNT production

• Ar gas responsible for TWCNT formation

• N₂ gas encouraged DWCNT production

[101]

Fe, W

H₂, Ar

200

70–120

• SWCNTs are synthesized with high yield

• Fe–W catalysts made SWCNT smaller than those using Fe catalyst alone

[173]

Ni/Y

Ar

12 kPa

90

• SWCNTs of diameter 1.29–1.62 nm are synthesized with higher oxidization temperature

[174]

Fe, Co, Ni, and FeS

H₂

240

120

• De-bundled SWCNTs with diameter 3 nm are synthesized

[175]

Ni, Co, F,S

Ar, H₂

350

75–80

• DWCNTs with outer diameter (1.9–5.0 nm) and inner tube diameters (1.1–4.2 nm) are obtained

[176]

Y–Ni/Co

Ar

–

40–60

• High-quality DWCNTs with inner and outer diameters 0.8–1.2 and 1.6–2.0 nm, respectively, are realized

[177]

Ni, Co, FeS, NiS, CoS, FeS, Sn

He

600

180

• High-quality DWCNTs with diameter (2–7 nm) super bundles are selectively grown

[178]

FeS

KCl

H₂

350

70

• DWCNTs with perfect lattice structure are synthesized with high yield

[179]

Ni(HCO₂)₂·2H₂O

H₂

240

120–300

• 65% of DWCNT are obtained within 10 min with narrow diameter distribution (outer 1.98–3.47 nm and inner 1.32–2.81 nm)

[180]

Ni/Co/Fe, Ye/La

Ar

760

50

• Highly pure DWCNT (95%) are achieved

[181]

Fe, S

Air

0.75–135

90

• FWCNT are effectively synthesized with diameter 1.6–6 nm

[182]

–

He

500

18

• MWCNT with diameter (5–30 nm) and length of several micrometers are secured

[85]

–

CH₄

50

20

• Thick MWCNTs are synthesized

[113]

–

H₂

60

50

• Fine and long MWCNTs are realized

[183]

Nd–Fe–B magnets

He, Ar, O₂, N₂, Air

750

~4.0 × 10¹¹ A/m²

• Obtained MWCNTs are highly pure (>95%)

• MWCNT purities are ~97% in (air), ~96% (Ar), ~40% (He), ~33% (N₂), and ~26% (O₂) gases

[184]

–

Liquid N₂

–

80

• 70% of MWCNT with diameter (20–50 nm) and a few μm in length is obtained

[119]

C₈H₁₀

C₁₀H₁₀F

–

500

10–70

• Both (SWCNTs and MWCNTs) are obtained

[185]

Co, S, Pt

H₂

300

100

• Environmental temperature showed a significant effect on the formation of MWCNTs as well as the diameter of the tubes

[186]

–

He

Air

500

150

• Highly graphitic MWCNT (yield 60%) in He atmp. and traces of DWCNT are secured

[144]

Nd-Fe-B magnet, Co metal

Water

–

50

• Purity and quality of obtained MWCNT are both improved markedly

• Co helped to get a cylinder-like CNT structure

[187]

Hydrocarbon compounds as precursors

He

300–600

30–90

• Thick MWCNTs are obtained

• Aromatic hydrocarbons, including pyrene and xylene, are suggested to not only act as precursors but also enhance the growth rate of MWCNT

[188]

–

Air

60

80

• Fine and long MWCNTs are obtained free from carbon nanoparticle and graphite platelet

[189]