Density functional theory calculations of XPS binding energy shift for nitrogen-containing graphene-like structures.

Our results validate the use of independent DFT predicted BE shifts for defect identification and constraining ambient pressure XPS observations for Me-Nx moieties in pyrolyzed carbon based ORR electrocatalysts. This supports the understanding of such catalysts as vacancy-and-substitution defects in a graphene-like matrix.

Reactions of CH3SH and (CH3)2S2 on the (0001) and (000) Surfaces of ZnO.

Temperature-programmed desorption (TPD) was used to study the adsorption and reaction of CH3SH and (CH3)2S2 on the (0001) and (000) surfaces of ZnO. The interaction of these molecules with ZnO was found to be structure-sensitive. Both CH3SH and (CH3)2S2 adsorb dissociatively on ZnO(0001), forming adsorbed methylthiolate intermediates and only molecularly on ZnO(000). In the case of CH3SH, this result is consistent with that reported previously for the interaction of Brønsted acids with ZnO and indicates that exposed cation-anion pairs are the active sites for dissociative adsorption. Only exposed Zn cations are required for the dissociative adsorption of (CH3)2S2. Methylthiolate species produced by dissociative adsorption of CH3SH and (CH3)2S2 on ZnO(0001) were found to undergo a variety of reaction pathways, including coupling to produce dimethyl sulfide and oxidation to formaldehyde, CO, and CO2. Pathways for the production of these various products are proposed.