Density functional theory study on adsorption of L-cysteine by Y, Zr, Nb, Mo-doped graphenes

The adsorption properties of l-cysteine (L-cys) on [Kr] 4d^1-4 (Y-Mo) doped graphenes with single and double vacancies are studied using density functional theory calculations with dispersion correction. The results showed that Y, Zr, Nb and Mo doped single-vacancy and double-vacancy graphenes show chemical adsorption characteristics towards L-cys. For the respective S, O and N-end adsorption, the binding strengths of L-cys on XSVs decrease from Y to Nb, and then increase. The binding strengths of L-cys on XDVs have no regular trend. Nb-doped graphene exhibits the most stable adsorption characteristics in the [Kr] 4d^1-4 element series, which is independent of the vacancy type. Zr-doped single and double vacancy graphene sensors have higher sensitivity than Y, Nb, Mo.