A study of the effect of the interaction between the active center and the ligand environment of ionomer-based catalysts on the oxygen evolution reaction

Abstract

Synthesiszing highly catalytically active and stable non noble metal oxygen evolution reaction (OER) catalysts with controlled coordination environments at room temperature and probing the relationship between coordination environments and active centers remain challenging. Herein, a series of monomeric particles composed of different coordination environments, Fe–(NH₂)₄–C, Fe–(NH₂)₃/OH–C, Fe–(NH₂)/(OH)₃–C and Fe–(NH₂)₂/(OH)₂–C, were synthesized by means of the response of chitosan salt (HACC) ionomers to pH values in solution at room temperature. The experimental results show that the active center of amine catalysts enables them to exhibit enhanced performance with a low overpotential of 255 mV at 10 mA cm⁻² maintaining favorable stability (only 1.3% loss of current density after 12 h) for the OER in a low amino coordination environment (Fe–NH₂/(OH)₃–C). Therefore, the selection of a suitable coordination environment is the key to the synthesis of efficient and highly stable ionomer-based catalysts. This work provides a practical reference for the design of efficient catalysts in the future.