title: Computational investigation of NH3 adsorption and dehydrogenation on a W-modified Fe(111) surface.
abstract: Hydrogen gas will play an important role in the future since it could be a replacement for gasoline, heating oil, natural gas, and other fuels. In previous reports ammonia (NH3), which has a high hydrogen content, provides a promising mode for the transferring and storing of hydrogen for its on-site generation. Therefore, the dehydrogenation of NH3 on a metal surface has been studied widely in the last few decades. In our study, we employed monolayer tungsten metal to modify the Fe(111) surface, denoted as W@Fe(111), and calculated the adsorption and dehydrogenation behaviors of NH3 on W@Fe(111) surface via first-principles calculations based on density functional theory (DFT). The three adsorption sites of the surface, top (T), 3-fold-shallow (S), and 3-fold-deep (D) were considered. The most stable structure of the NHx (x = 0-3) species on the surface of W@Fe(111) have been predicted. The calculated activation energies for NHx (x = 1-3) dehydrogenations are 19.29 kcal mol(-1) (for H2N-H bond activation), 29.17 kcal mol(-1) (for HN-H bond activation) and 27.94 kcal mol(-1) (for N-H bond activation), and the entire process is exothermic by 33.05 kcal mol(-1). To gain detailed knowledge of the catalytic processes of the NH3 molecule on the W@Fe(111) surface, the physical insights between the adsorbate/substrate interaction and interface morphology were subjected to a detailed electronic analysis.
authors.affiliation: Department of Chemistry and Institute of Applied Chemistry, Chinese Culture University, Taipei, 111, Taiwan. chl3@faculty.pccu.edu.tw.
authors.forename: Ming-Kai
authors.initials: MK
authors.lastname: Hsiao
authors.affiliation: Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Su
authors.affiliation: Department of Chemistry and Institute of Applied Chemistry, Chinese Culture University, Taipei, 111, Taiwan. chl3@faculty.pccu.edu.tw.
authors.forename: Ching-Yang
authors.initials: CY
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Institute of Applied Chemistry, Chinese Culture University, Taipei, 111, Taiwan. chl3@faculty.pccu.edu.tw.
authors.forename: Hui-Lung
authors.initials: HL
authors.lastname: Chen