Non-Precious Metal Oxygen Reduction Electrocatalyst from Pyrolyzing Cobalt Tetraethylenepentamine Complex on Carbon

Abstract

Development of non-precious metal catalysts for oxygen reduction reaction (ORR) is of great importance due to their significant potential application in energy converting and storing devices. In this work, based on the simple and low-cost N5 structure tetraethylenepentamine (TEPA) ligand, a class of non-precious metal catalyst is prepared from pyrolyzing cobalt tetraethylenepentamine chelate on carbon (CoTEPA/C) at 800°C in high purity N2. It indicates that the cobalt-nitrogen chelate decomposes and metallic Co nanoparticles are present after pyrolysis. The optimized CoTEPA/C catalyst is found at the nominal mole ratio of Co:TEPA = 1:4 with more defect degree and smaller Co particles. For this catalyst, the nitrogen content is 1.12 at% mainly in pyridinic-N form. Electrochemical results show that this catalyst has a good catalytic activity and selectivity to water (4e reaction pathway) both in acid and alkaline electrolytes among the potential we studied. Furthermore, a better catalytic performance in terms of ORR peak potential (0.973 V vs. RHE), onset potential, half-wave potential and selectivity to water in alkaline medium is displayed. © 2014 The Electrochemical Society. All rights reserved.