• Ni dopant facilitates the dissociative adsorption of H 2 S on ZnO. • H 2 O formation in H 2 S removal process is significantly promoted on Ni-doped ZnO. • SH at Ni site directly serve as hydrogen source for OH hydrogenation to form H 2 O. • Surface s atom nearby Ni more easily penetrates toward inner O v sites of ZnO bulk. H 2 S removal and ZnO initial sulfuration over ZnO nanowire are investigated using density functional theory (DFT) calculations, and the promotion effects of Ni-doping are discussed in detail. H 2 S can molecularly and dissociatively adsorb on pure and Ni-doped ZnO. Our results suggest that H 2 S prefers to adsorb dissociatively at Ni atom, mirrored by lower dissociated adsorption energies. For H 2 S removal, H 2 O formation is generally difficult on ZnO with a high energy barrier of approximately 2 eV. In contrast, we demonstrate that Ni could significantly promote H 2 O formation. The SH group at Ni site directly serves as hydrogen source for OH hydrogenation to form H 2 O, with much lower energy barriers of less than 1 eV. The retained S atom nearby Ni more easily penetrates toward inner sites of ZnO bulk. The present work clearly indicates that H 2 S removal and ZnO initial sulfuration preferentially occur in the vicinity of Ni dopant. [Display omitted] [ABSTRACT FROM AUTHOR]