Enhanced cathodic catalytic activity of an N-doped micropore structure obtained through the six-coordinate bond of an EDTA-Ce composite for the oxygen reduction reaction

Abstract The development of catalytic materials to increase the efficiency of the oxygen reduction reaction (ORR), which effects an important role in next generation energy storage and conversion systems, is essential but challenging. Electrocatalysts for ORR in alkaline solution, including Ce/N-doped micropore carbon materials (CNMCs), are prepared as nonprecious-metal catalysts from an ethylenediaminetetraacetic acid (EDTA) and cerium (III) nitrate hexahydrate complex. The material obtained via a simple manual synthesis method has a microporous and octahedral structure as a result of six-coordinate bonds between EDTA and Ce metals. The CNMC materials have high surface areas, which advantageous for electrochemical catalysts. Furthermore, the micropore structure positively affects the ORR by allowing three phases (solid/catalyst–liquid/electrolyte–gas/oxygen) to coexist in a wide range. Ultimately, a new cathodic catalyst based on EDTA, which has not been reported thus far, is obtained after the optimal Ce content is determined. The electrocatalytic performance of CNMCs toward the ORR is characterized using a rotating disk electrode (RDE) technique. The RDE results obtained with the CNMCs reveal an onset-potential and half-wave potential similar to those of a Pt/C catalyst. In addition, the CNMCs exhibit good long-term stability and excellent durability. Therefore, these materials may be alternative cathode electrocatalysts in commercial use.