Adsorption of hydrogen and hydrogen-containing gases on Pd- and Ag-single atoms doped on anatase TiO_2 (101) surfaces and their sensing performance

摘要

The Pd and Agdoped anatase TiO2 (1 0 1) surfaces were investigated and the binding energies of single atom of Pd (-2.15 eV) and Ag (-2.38 eV) on the anatase (1 0 1) surfaces, respectively denoted as Pd/TiO2 and Ag/TiO2, were obtained. Binding sites for Pd and Ag atoms toward the TiO2 surface atoms are three atoms (Ti-5C and two O-2C atoms) and two O-2C atoms of the TiO2 (1 0 1) surface, respectively. Due to adsorptions of H-2 and hydrogencontaining (H2O, NH3, and CH4) gases on the Pd/TiO2 and Ag/TiO2, adsorption abilities on the Pd/TiO2 and Ag/TiO2 are in decreasing orders: NH3 H2O H-2 CH4 and NH3 H2O CH4 H-2, respectively. Mullikencharge transfers from the Pd and Ag atoms to adsorption atoms of the anatase TiO2 (1 0 1) surface and the adsorption of hydrogen and hydrogencontaining gases to the Pd/TiO2 and Ag/TiO2 were observed. The Pd/TiO2 and/or Ag/TiO2 have high potentials to be NH3 sensing materials based on the electric conductivity measurement. The Pd/TiO2 has high potential to be CH4 sensing device based on the electric conductivity and surface charge measurements. (C) 2018 Elsevier B.V. All rights reserved.