PtM (M = Ni,Co,Cu)/C CATALISTS: SYNTHESIS, STRUCTURE, ACTIVITY IN OXYGEN REDACTION AND METHANOL OXIDATION REACTION

Abstract

The purpose of this work is study to correlation between structure, electrochemically active surface area and activity in the oxygen reduction reaction and methanol electrooxydation of obtained by wet-synthesis PtM/C (M = Ni, Co, Cu) materials with atomic ratio Pt-M 1:1 and a commercial Pt/C material E-TEK 20.

Bimetallic PtM/C electrocatalysts were obtained by chemical reduction of metals from their compounds a carbon (Vulcan XC-72, Cabot) suspension based on two-component water-organic solvent at pH = 10 (excess of NH₃). The characterization of PtM/C materials was performed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and cycle voltammetry (CV).

The average crystallite size according XRD for the received materials have from 1.7 to 2.5 nm and a platinum content of materials is 20 – 27% by weight. It was found that PtM/C catalysts have a smaller value of surface area - 40 m²/g (Pt) as compared with Pt/C catalyst - 100 m²/g(Pt). But despite this fact mass-activity (activity per mass of platinum, A/g(Pt)) in the oxygen reduction reaction (ORR) PtCu/C catalyst have not inferior to commercial Pt/C material. All of PtM/C materials demonstrated a high specific activity (activity per real surface area, mA/cm²) in the reaction of methanol oxidation (MOR) and a high tolerance for intermediate of methanol oxidation.

It was found that the alloying of various d-metals can have a positive effect on the activity in the reaction of oxygen electroreduction, methanol electrooxydation and a high tolerance for intermediate of methanol oxidation. However, for increase of the mass-activity it necessary to obtain of PtM/C catalysts with higher surface area.

ACKNOWLEDGEMENTS

The authors thank the Russian Foundation for Basic Research (project 16-38-60112 mol_a_dk) for the financial support of research.