HYDROGEN ADSORPTION ON A PT(110)-(1 X-2) SURFACE

Low-energy electron diffraction (LEED), temperature-programmed desorption (TPD) and the work function change, which was measured by a mirror-electron-microscope-LEED were used to study the adsorption of hydrogen on the (1 x 2) reconstructed surface of Pt(110) at T = 170 K. Two adsorbed states beta(1) and beta(2) were found in the TPD spectra. The state beta(1) belongs to first-order desorption while the state beta(2) is second-order desorption. The initial sticking coefficient is 0.8. The change of work function, DELTA-W, is positive at low coverage and (DELTA-W)max = 0.15 eV at a relative coverage R of 0.05. DELTA-W becomes negative as R increases to 0.2, and (DELTA-W)max = -0.6 eV at saturation coverage. No new LEED pattern was observed in this adsorption. The possible adsorption sites of different geometrical positions are discussed.