Two dimensional metal-oxianion surface complexes formation during the upd process on a Au(111) electrode studied by in situ surface X-ray diffraction and infrared reflection absorption spectroscopy

摘要

Throughout the whole potential ranges where underpotential deposition (upd) proceeds, the stretching absorption bands of both sulfate and phosphate anions (v_(S-O) and v_(P-O)) do not change at all with regard to band-center position. Sulfate and phosphate anions are combined with copper or zinc ions to form surface metal complexes on a Au(111) electrode surface, respectively: transition metal-oxidation (sulfate and phosphate) pseudo-complexes are formed in the course of upd processes. The surface structure of the Au(111) electrode in the topmost layer is the same as the bulk structure (1 * 1), and lifting of surface reconstruction takes place in the case of Cu-upd where Cu(I)_2SO_4 and Cu(I)_3SO_4 pseudo-complexes extend on the surface, while surface reconstruction of a Au(111) electrode continues to occur in the case of Zn-upd where the Zn(I)_2PO_4 or Zn(I)_3PO_4 pseudo-complex locates.