Alkali-Tuning Hemin-Derived Pore-Rich Fe-N-C: A Remarkable and Durable Electrocatalyst Toward Oxygen Reduction in Alkaline and Acid Condition

Exploring highly efficient and durable nonprecious materials to change commercial Pt/C toward oxygen reduction reaction (ORR) is critical to the large-scale application of electrochemical conversion systems. In this study, a novel KOH-tuning strategy is reported to prepare the hemin-derived iron and nitrogen dual-doped carbon electrocatalyst for ORR. In the fabrication process, the KOH solvent plays three roles: (i) replacing toxic dimethylformamide (DMF) to achieve the environmentally friendly dissolution; (ii) converting insoluble hemin into soluble hematin porcine to ensure the uniform dispersion; and (iii) adjusting the chemical composition and crystal structure to accelerate the reduction reaction. The experimental investigation demonstrates that the surface chemical composition and the graphitization degree of the carbon tuned by 0.01 M KOH are improved, resulting in better activity and selectivity than the catalyst without KOH. Furthermore, the half-wave potential of the developed catalyst is more effective and more durable than Pt/C in alkaline and acidic conditions. This alkaline tuning strategy provides an effective and promising approach to develop high-performance catalysts toward ORR.