The application of N-doped distillers' grains porous carbon in the oxygen reduction reaction

The scarcity and poor cycle stability of platinum, the key catalyst for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries, necessitate the development of alternative catalysts that are low-cost yet highly efficient. In this study, a novel catalyst was synthesized through chemical activation and nitrogen doping of distillers' grains, a biomass material that is rich in heteroatoms. Under alkaline conditions (0.1 M KOH), the ORR peak potential (0.833 V) of the resulting catalyst is comparable to that of commercial Pt/C (0.844 V), with a halfwave potential(E1/2) of 0.802 V, achieving 97.3 % of the Pt/C performance. The onset potential (Eonset) of 0.93 V is also close to that of Pt/C (0.94 V). When the catalyst loading is increased to 0.75 mg/cm2, it exhibits a similar current density, E1/2 of 0.81 V, and Eonset of 0.98 V, even surpassing Pt/C. Stability tests using the i-t method show a current decay of 23.96 % after 12 h, outperforming the 79.71 % decay observed for Pt/C. Furthermore, the catalyst demonstrates superior methanol tolerance. In addition to providing a new way to utilize distillers' grains, the new catalyst achieves catalytic properties comparable to commercial Pt/C catalysts while controlling costs, and is expected to be a potential alternative to Pt/C catalysts for applications.