Specific features of the formation of Pt(Cu) catalysts by galvanic displacement with carbon nanowalls used as support

Microamounts of Cu are applied by the methods of electrodeposition (Cued) and magnetron sputtering (Cuspr) on a new carbon material, carbon nanowalls (CNW). The galvanic displacement (GD) of Cued and Cuspr in a PtCl42− solution (with 0.5 M H2SO4 as the supporting electrolyte) produces Pt(Cu)/CNW catalysts. The possibility of using open-circuit potential transients recorded in the course of GD for monitoring the surface layer composition is considered. The stable Pt(Cu)st samples are characterized by several methods (SEM, TEM, XPS, voltammetry, etc.). It is shown that Pt(Cu)st has structure of the core(Pt, Cu)–shell(Pt) type with the average atomic ratio Pt:Cu (%) ∼ 57:43 for Cued and ∼80:20 for Cuspr. The formation of the dense Pt shell is also confirmed by the data on the electrocatalytic activity of synthesized samples in the methanol oxidation reaction. The reasons for deviations in the properties of Pt(Cu)st/CNW samples formed from Cued and Cuspr are discussed. The high specific surfaces of the Pt(Cu)st/CNW catalyst obtained from Cued (>40 m2/g Pt) with the simultaneous decrease in the Pt content makes this material promising for using in the platinum-catalyzed processes (particularly, in fuel cells).

► Electrodeposition or magnetron sputtering of Cu on carbon nanowalls (Cued/CNW or Cuspr/CNW).
► Galvanic displacement in PtCl42− solution.
► Formation of Pt(Cu)st/CNW catalyst.
► Characterization of samples by the complex of methods (SEM, TEM, XPS, voltammetry, polarization curves in CH3OH solutions and so on).
► Discussion of the mechanism of formation and the structure of Pt(Cu)st/CNW.