ORR Catalysts Based on Carbon Nanotubes and Metal Phthalocyanines Obtained by High-Temperature Synthesis

Abstract

Bi- and trimetallic catalysts based on multi-walled carbon nanotubes (MWCNT) and metal (Me) phthalocyanines (Pc) (MePc) (MWCNT–CoPc–NiPc, MWCNT–CuPc–NiPc, MWCNT–CoPc–CuPc, and MWCNT–CoPc–CuPc–Pd) for electrochemical oxygen reduction reaction (ORR) were synthesized by high-temperature synthesis at 1000°C in an inert atmosphere. The obtained materials were characterized by scanning electron microscopy (SEM), low-temperature nitrogen absorption–desorption, and Raman spectroscopy. The change in textural characteristics and morphology of electrocatalysts during high-temperature synthesis was studied. It was shown that the nature of the metal significantly changes the physicochemical characteristics of electrocatalysts based on carbon nanotubes. The electrochemical experiment was carried out in the linear voltammetry algorithm using a three-electrode chamber with a rotating disk electrode. The main characteristics of the process of electroreduction of oxygen from an alkaline electrolyte—limiting diffusion current, potential half-waves, and initial reaction potential—were determined. MWCNT–CoPc–CuPc–Pd catalyst was found to exhibit the highest activity in the reaction of electrochemical oxygen reduction in an alkaline liquid, reaching high efficiency and corrosiveness as with platinum catalysts, with a decrease in activity after 1000 cycles of less than 7%.