Metal–organic framework-loaded carbon-encapsulated nano-catalyst as a pH-universal oxygen reduction reaction electrocatalyst for various fuel cell devices

Abstract

As the quality of fossil fuels declines and environmental contamination worsens, for the next generation of sustainable energy storage technologies, fuel cells have enormous potential. However, the kinetics of the oxygen redox processes at an air cathode are very asymmetric, which leads to low energy efficiency and a short cycle life, particularly under conditions of huge area capacity and current densities. The creation of highly active and stable nonprecious metal catalysts (NPMCs) to replace Pt-based materials remains a significant challenge in comparison to the extensively studied oxygen reduction reaction (ORR) catalysis under alkaline conditions. Due to their abundant sources, environmental friendliness, and low cost, B, N co-doped carbon-based (BNCs) materials have rapidly emerged as feasible substitute catalysts for the ORR. Here, we introduce a brand-new, carbon-coated FeN_0.056, B, N co-doped catalyst that is equally highly active and stable. Notably, the resulting catalyst exhibits surpassingly improved ORR activity and sufficient potential cycling stability under a pH-universal electrolyte environment, which can be applied to Zn–air batteries (ZABs) in alkaline electrolytes, microbial fuel cells (MFCs) in neutral electrolytes and direct methanol fuel cells (DMFCs) in acidic electrolytes. Combined with earlier observations, the catalyst that we learned would lead to a fresh discussion in the field for comprehending the pH-universal electrolyte environment during ORR electrocatalysis.