Facile synthesis of high-density and vertically aligned carbon nanotube arrays on an acid treated stainless steel mesh

Abstract

Directly growing vertically aligned carbon nanotube arrays (VACNTs) on conductive substrates has shown great potential in a wide variety of applications. Among the various substrates, stainless steel (SS) possesses the advantageous features of wide availability, diverse compositions, and Fe containing, all of which are favorable for direct use as a low-cost and efficient catalytic substrate for VACNT growth. However, it is still unachieved to grow high-density VACNTs on SS in a facile way due to the lack of effective engineering strategies on the SS surface. Herein, we demonstrate a facile but efficient method to grow dense and highly VACNTs on an SS mesh by simply etching the SS mesh with an optimized HCl solution. Experimental results show that the etching can remove the chromium-rich passive layer and create highly active sites for chemical vapor deposition. In addition, it is revealed that the presence of the high-melting element of Mo in SS 316 is essential for prolonging the lifetime of active sites. Compared to the case on the SS 304 without Mo element, the VACNTs grown on SS 316 exhibit a higher purity, better alignment, higher degree of graphitization, and more importantly, large height of 80 μm.