Synthesis and Evaluation of Hollow Structured Gd-Co-N-PC Electrocatalysts Originating from MOFs for Effective Oxygen Reduction Reaction

Abstract

Platinum remains the predominant catalyst for the oxygen reduction reaction (ORR) occurring at both the cathode and anode in fuel cells and metal–air batteries; however, its elevated expense, shortage, and restricted consistency in alkaline environments hinder widespread commercialization. To overcome these constraints, this research emphasizes the creation and assessment of a novel multimetallic electrocatalyst obtained from metal–organic frameworks (MOFs) and stabilized with a silicate coating. A hollow-structured catalyst was prepared by carbonizing ZIF-8@Gd-ZIF-67@SiO₂, with mesoporous silica (mSiO₂) applied to prevent particle aggregation during high-temperature pyrolysis. The integration of carbon frameworks, metal doping, and silica protection effectively enhanced the structural integrity and catalytic performance. Detailed physical and electrochemical studies showed that the newly developed electrocatalysts had a consistent shape, nanoscale particle sizes, and high surface areas. Compared to commercial Pt/C (20%), the Gd-Co-N-PC electrocatalyst achieved an onset potential of –0.12 V and an electron transfer count of 3.69, suggesting a near-four-electron ORR pathway and superior catalytic activity. Stability tests further confirmed its excellent durability under operational conditions. Overall, the developed electrocatalysts offer a promising, cost-effective alternative to platinum-based materials for fuel cell applications, combining high ORR efficiency with robust structural stability for future energy conversion technologies.