Experimental and theoretical study of the reactions between MO2- (M = Fe, Co, Ni, Cu, and Zn) cluster anions and hydrogen sulfide.

Transition metal oxide cluster anions Mm18On– (M = Fe, Co, Ni, Cu, and Zn) were prepared by laser ablation and reacted with H2S in a fast flow reactor under thermal collision conditions. A time-of-flight mass spectrometer was used to detect the cluster distributions before and after the interactions with H2S. The experiments reveal a suite of oxygen/sulfur (O/S) exchange and oxygen/sulfydryl (O/SH) exchange reactions. The O/S exchange reaction to release water was evidenced for all of the MO2– cluster anions: MO2– + H2S → MOS– + H2O, whereas the O/SH exchange reaction to derive MOSH– and OH species was only observed for reactions of NiO2–, CuO2–, and ZnO2–. Density functional theory calculations were performed for reaction mechanisms of MO2– + H2S (M = Fe, Co, Ni, Cu, and Zn). The computational results are generally in good agreement with the experimental results. This gas-phase study provides an insight into the metal dependent reactivity in the removal of H2S over metal oxides.