Three-dimensional analysis of the local structure of Cu on TiO₂(110) by in situ polarization-dependent total-reflection fluorescence XAFS

Cu K-edge XAFS of Cu/TiO₂(110) was measured by polarization-dependent total-reflection fluorescence XAFS technique. XAFS of [001], and [110] directions were measured to elucidate the three dimensional structure of Cu species on the TiO₂(110) surface prepared by the deposition of Cu(DPM)₂ followed by reduction with H₂. Simulation of the EXAFS functions as well as conventional curve fitting analysis revealed that plane Cu_3-4 small clusters with similar structure to Cu(111) plane were formed by the reduction at 363 K. The small clusters converted into spherical metallic Cu particles by the reduction at 473 K.