(214f) Metallocene-Functionalized Boron-Doped Nanocarbons for Electrochemical Applications

We have conducted a first-principles density-functional theory study on the electronic and electrochemical properties of cyclopentadienyl-transition metal (CpTM, with TM = Fe, Co, Ni) complexes adsorbed on pristine and boron-doped single-walled carbon nanotubes (B-CNTs) and graphenes, which may serve as new electrochemical catalysts or redox-active materials for electrochemical sensing. By using first-principles DFT calculations and ab initio molecular dynamics, we predict significant structural stablization by using B-CNT substrates, and we identify promising potential applications as electrochemical catalysts. Relevant to the well-studied electrochemical donor-acceptor molecule ferrocene, new CpFe/B-CNT or graphene-based electrochemical redox active materials may benefit from both the redox activity of the ferrocene and the superior stability and conductivity of B-doped nanocarbons. Therefore, the redox potentials of these complexes within aqueous solutions as well as in acetonitrile (MeCN) are calculated to evaluate their potential applications in electrochemical sensing. The calculated redox potentials of our catalysts are similar to those of ferrocene molecules, and this indicates the possibility of using these materials as ferrocene substitutes for electrochemical applications. Moreover, the effects of different B-CNT support chirality, doping patterns, and Cp sidechains on the redox potentials are also benchmarked.  In addition to the redox calculations, the electron transfer details of the CpFe/B-graphene complex during the redox reactions are clarified by analyzing the natural bond order partial charges and by performing deformation charge density analyses.