Enhanced Electrochemical Performance Through Morphology-Controlled Co/N/C Catalysts: A Strategy for Optimized Electrode Architecture

Abstract

This study presents a novel strategy to enhance the performance of carbon-based non-precious metal catalysts (NPMCs) for electrochemical applications by controlling their electrode architecture through catalyst morphology optimization. The approach involves the self-assembly of zinc-based zeolitic imidazolate framework nanocrystals using cobalt ions as crosslinkers, followed by carbonization. This process yields morphology-controlled Co/N/C catalysts with a uniform size (0.5 µm), well-defined structure, and significantly higher tap density (1.7 ×) compared to irregularly shaped Co/N/C catalysts. Electrodes fabricated using the morphology-controlled catalysts demonstrated superior oxygen reduction reaction (ORR) performance in gas diffusion electrodes, attributed to reduced electrode thickness and enhanced transport properties. Despite similar intrinsic kinetic activities, the uniform morphology improved electronic/ionic conductivity and minimized mass transport losses, resulting in higher catalyst utilization efficiency. These findings highlight the critical role of electrode architecture in improving the performance of carbon-based catalysts, offering promising implications for energy conversion and storage systems, such as fuel cells and batteries.