Growth of carbon nanotube forests on flexible metal substrates: Advances, challenges, and applications

Interfacing Dense NiFe@N-Doped Carbon Nanotubes on a Ni Hollow Fiber as a High-Current-Density Gas-Penetrable Electrode for Selective CO2 Electroreduction

“…It has been previously reported that when Ni-based catalysts were used as the catalyst for the growth of carbon nanotubes (CNTs), alloying Ni with Fe can lower the formation energy of catalytic active sites and the ratio of Ni to Fe has a great effect on its catalytic activity toward the growth of CNT. 35,36 Thus, in the present work, it can be inferred that both the Ni-rich NiFe catalyst formed at lower ferrocene amounts and the Fe-rich NiFe alloy catalyst formed at higher ferrocene amounts are not effective in catalyzing the growth of CNTs, and only when 16 mg of ferrocene was used, an active NiFe alloy catalyst is formed (as evidenced by TEM analysis) and effectively catalyzes the formation of a high-dense NCNTs covering the surface of Ni HF (Figure S7).…”

Super Black Coating on the Commercial Black Anodized Al(6061) by Direct and Scalable CVD–Growth of Carbon Nanofibers

“…Prior to synthesis, the commercial black anodized Al(6061) was annealed in an oven at 80 °C for 10 h to form a uniform layer of Ni catalyst in the black dye-coated anodized Al(6061), which is necessary to enhance the efficient growth of carbon nanostructures. [32,33] The substrate was vertically loaded inside zone 2 of the CVD chamber, after which zone 1 was heated to 750 °C for 1 h in Ar gas (400 sccm) and H 2 gas (200 sccm), and the temperature of zone 2 was 550 °C. Then, the substrate was kept at that temperature for 10 min to allow catalyst annealing under mostly H 2 gas flow, followed by C 2 H 4 gas flow (400 sccm) to initiate CNF growth.…”

Field Emission from Carbon Nanotubes on Titanium Nitride-Coated Planar and 3D-Printed Substrates

“…Note that the macroscopic electric field was defined as the ratio of the applied voltage to the electrode distance of 250 µm. The general turn-on field reduction is likely related to the good electrical conductivity of the TiN film, which allowed for an efficient electron supply across the substrate towards the CNTs and, possibly, generated a lower CNT-substrate contact resistance [9,10,49]. Furthermore, the highest turn-on field of 2.9 V/µm was found for the pristine, electrically insulating SiN, which emphasizes the influence of the substrate's electrical properties on the CNTs' FE performance.…”

“…Therefore, a metal substrate would be the ideal choice to provide a low contact resistance resulting in an efficient electron supply towards the CNTs. Moreover, a metallic substrate would allow for adequate heat dissipation, preventing emitter-substrate bond degradation [9,10]. However, the chemical vapor deposition (CVD) growth of CNTs on metal substrates is known to be challenging in contrast to substrates like silicon or quartz.…”

“…However, the chemical vapor deposition (CVD) growth of CNTs on metal substrates is known to be challenging in contrast to substrates like silicon or quartz. Metals have lower melting points that can be incompatible with CVD growth temperatures, they show an enhanced probability for chemical or physical reaction with the catalyst material (such as iron, nickel, or cobalt) needed for CNT growth, and their higher surface roughness provokes inhomogeneous catalyst particle distributions [10,11]. These substrate properties can have a strong influence on the resulting CNT structure and yield, or even prevent CNT growth on the metal substrate.…”