DFT study of chemisorption of Zn(II)/gamma-MnOOH system

Three kinds of adsorption species(hydrated, 1st hydrolysis and 2nd hydrolysis) in Zn(II)/gamma-MnOOH system were calculated with DFT-B3LYP method. The thermochemistry analysis indicate that the stability order of the adsorption species was DC > SE-B > SE-A > DE for the hydrated species, and DC > SE-A > SE-B > DE for hydrolysis species, which obeyed the 3rd law of Pauling. The adsorptive process and hydrolytic process always show an inter-antagonistic relationship in this system, which is also consistent with the frontier molecular orbital analysis. Natural population analysis indicate that electronic transfer from cluster model to Zn-O unit was occurred clearly during adsorptive process, which give a reasonable explanation for the stabilization of adsorption species combining with electronic donor-acceptor and frontier molecular orbital analysis.