Surface reactions of AsH3, H2Se, and H2S on the Zn2TiO4(010) surface

Removal of toxic species such as As, Se, and S is critical to the successful implementation of high efficiency Integrated Gasification Combined Cycle (IGCC) processes for coal utilization. In this work we study the initial low-coverage surface reactions of AsH3, H2Se and H2S with a regenerable sorbent, zinc orthotitanate (Zn2TiO4), using first principles density functional theory. AsH3 adsorbs more preferentially on oxygen-rich (010) surfaces, while H2Se and H2S are more favorably bound to metal-rich (010) surfaces. We calculated the dissociation pathways and rates for each adsorbed species, finding that dehydrogenation of AsH3, H2Se, and H2S should be facile on these surfaces at the high temperatures relevant for IGCC processes.