Insights into the use of Au19Cu and Au19Pd clusters for adsorption of trivalent arsenic

Abstract

The adsorption of trivalent arsenic [As(OH)3] onto the bimetallic Au19Cu and Au19Pd clusters was computationally studied to get insights about as embedded electrodes with bimetallic gold nanostructures can serve for the adsorption and subsequent sensing of arsenic traces from polluted waters. It was found that the As(OH)3 chemisorption onto Au19Cu and Au19Pd is reached with adsorption energies of up to 1.02 and 1.48 eV, respectively, with even a stable physisorption with energies of up to 0.57 eV. Both arsenic and oxygen atoms were determined to bind with adsorbent Cu and Pd atoms, and all the interactions appear to be stable in an aqueous environment. The stability of the adsorbent–pollutant interactions was explained in terms of metal–pollutant chemical binding, charge transfer, dispersion force interactions and non-conventional OH···Au hydrogen bonds. Moreover, the As(OH)3 adsorption on the metal clusters is also accompanied by changes in the reactivity, electron transfer and decreases of the HOMO–LUMO energy gap with respect to the isolated substrates; the highest changes obtained in the mentioned properties are classified in the order Au19Pd > Au19Cu > Au20.