Ab initio Study of Aspirin Adsorption on Single-walled Carbon and Carbon Nitride Nanotubes

TL;DR

This study uses ab initio density functional theory to compare aspirin adsorption on carbon nanotubes and carbon nitride nanotubes, revealing stronger binding and electric field effects on the latter, with implications for sensor development.

Contribution

It is the first detailed ab initio investigation of aspirin adsorption on both CNT and CNNT, highlighting the role of N atoms and electric fields in adsorption behavior.

Findings

Aspirin binds more strongly to CNNT than CNT.

Electric fields can induce aspirin states in CNNT's band gap.

CNNT's N atoms enhance reactivity and charge redistribution.

Abstract

We use ab intio density functional theory to investigate the adsorption properties of acetylsalicylic acid or aspirin on a (10, 0) carbon nanotube (CNT) and a (8, 0) triazine-based graphitic carbon nitride nanotube (CNNT). It is found that an aspirin molecule binds stronger to the CNNT with its adsorption energy of 0.67 eV than to the CNT with 0.51 eV. The stronger adsorption energy on the CNNT is ascribed to the high reactivity of its N atoms with high electron affinity. The CNNT exhibits local electric dipole moments, which cause strong charge redistribution in the aspirin molecule adsorbed on the CNNT than on the CNT. We also explore the influence of an external electric field on the adsorption properties of aspirin on these nanotubes by examining the modifications in their electronic band structures, partial densities of states, and charge distributions. It is found that an electric field applied along a particular direction induces aspirin molecular states in the in-gap region of the CNNT implying a potential application of aspirin detection.