CO adsorption on ultra-small carbon nanotubes decorated with single transition metal atoms

One of several important aspects in developing CO sensors is to find the superior nanomaterials used as sensor materials. Thus, we propose a new candidate such as single transition metal atoms decorated an ultra-small carbon nanotube (CNT) to be investigated for this purpose. This research begins with an understanding of the interaction mechanism of: (a) single transition metal atoms period 4 on an ultra-small CNT, and (b) carbon monoxide (CO) on these single transition metal atoms decorated an ultra-small CNT, using density functional theory (DFT) calculation. Based on the results, we can conclude that nine out of ten transition metal atoms of period 4, such as scandium (Sc), titanium (Ti), vanadium (V), chrome (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu), all had strong interactions with the ultra-small (5, 5) CNT due to their high spontaneous adsorption, d band center position, bonding formation and charge distribution. However, the best candidate of a sensor material for CO detecting among all transition metals is a single Ni decorated ultra-small (5, 5) CNT. On the other hand, zinc (Zn) has such the weakest interaction with an ultra-small (5, 5) CNT, making the Zn decorated ultra-small (5, 5) CNT a poor candidate for a CO sensor material.