Surface X-ray scattering of high index plane of platinum containing kink atoms in solid-liquid interface: Pt(3 1 0) = 3(1 0 0)-(1 1 0)

Surface structure of Pt(3 1 0) = 3(1 0 0)-(1 1 0), which contains kink atoms in the step, has been determined with the use of in situ surface X-ray scattering (SXS) in the double layer region (0.50 V(RHE)) in 0.1 M HClO₄. Clean Pt(3 1 0) surface has pseudo (1 × 1) structure on which lateral displacements of 2-9% and 0.3-1% are found along a and b directions, respectively, whereas the surfaces of Pt(1 1 0) = 2(1 1 1)-(1 1 1) and Pt(3 1 1) = 2(1 0 0)-(1 1 1) are reconstructed to (1 × 2) according to previous reports. Interlayer spacing between the first and the second layers d₁₂ is contracted about 5% compared with the bulk spacing, whereas those between underlying layers are expanded down to fourth layer. Fully adsorbed CO has no effect on the surface structure of Pt(3 1 0). This result differs from that on Pt(1 1 1), where d₁₂ is expanded after CO adsorption.