Density functional study of H2O adsorption and dissociation on WC(0001)

作者：Zheng, Wanfang; Chen, Litao^*; Ma, Chun'an

来源：Computational and Theoretical Chemistry, 2014, 1039: 75-80.

DOI：10.1016/j.comptc.2014.04.031

• Density functional theory
• Adsorption
• Dissociation
• Water

Adsorption and dissociation of water on the W- and C-terminated WC(0 0 0 1) surfaces have been studied with periodical slab model by PW91 approach of GGA within the framework of density functional theory (DFT). Adsorption energies, preferred adsorption sites, and configurations for H2O and its dissociation products (OH, H, and O) are determined, as are the minimum energy paths of H2O decomposition. Our results suggest H2O, OH and O bind preferentially on the metal surface, while H prefers C termination over W termination. For the W-terminated surface, the barriers of H2O dehydrogenation are 0.74 eV for the removal of hydrogen from the H2O to produce adsorbed OH and 0.75 eV for the subsequent decomposition of OH to hydrogen and oxygen. For the C-terminated surface, the corresponding barriers of two dehydrogenation steps are 0.09 eV and 0.44 eV respectively. Both dissociation steps are found to be highly exothermic on the W- and C-terminated surfaces. The H-2 desorption from the C-terminated surface is unlikely due to the formation of stable C-H bond, but it is easy to happen on the metal surface. Compared to Pt(1 1 1), the results here indicate that the activity of WC(0 0 0 1) toward the decomposition of water is significantly higher.

• 出版日期2014-7-1
• 单位浙江工业大学