The oxygen reduction reaction (ORR) that occurs in the cathode of fuel cells is a major issue in proton exchange membrane fuel cells (PEMFCs) due to their sluggish kinetics. Exploring suitable materials for use as cathode catalysts can be challenging because the materials should be chemically active yet must be stable in an extremely corrosive environment in fuel cells. Since the successful introduction of graphene, 2-dimensional (2D) materials have received extensive research interest regarding their use as support materials for cathode catalysts due to their large surface area for catalyst dispersion. Recently, research on 2D MXene-based catalyst supports has started to increase. Excellent electronic properties, electrical conductivity, hydrophilicity and chemical and thermal stability are the key properties of potential MXenes used as catalyst supports. Therefore, in this review, the properties and performance of 2D MXene-based catalyst supports in the ORR are comprehensively discussed. This finding provides the groundwork for the exploration of MXenes in electrocatalysis, especially in the ORR. Challenges and future research directions are also discussed in this review.

The development of nonnoble metal oxygen reduction reaction (ORR) catalysts for fuel cells has been motivated by the high cost and limited supply of noble metals, as well as the desire to improve the performance and durability of this type of energy conversion device. In this study, nonnoble Fe–N–C catalyst was synthesized using a zeolitic imidazole framework (ZIF‐8), poly (aniline), and 10,10′‐dibromo‐9,9′‐bianthry as precursors to produce Fe–N–C with hollow sphere (HS), amorphous bulky structure (B), and sheet‐like thin sheet (N) structure. The Fe–N–C catalyst was analysed in terms of their shape, crystal structure, pore characteristics, and elemental composition. Among all the Fe–N–C catalysts, Fe–N–C_HS had the highest total surface area, followed by Fe–N–C_B and Fe–N–C_N. To evaluate their ORR catalytic activity, a half‐cell electrochemical experiment with .1 M KOH and .1 M HClO4 as the alkaline and acidic electrolytes was conducted. This study revealed that Fe–N–C_HS exhibited the highest onset potential but the Fe–N–C_B has the highest limiting current density in alkaline medium; meanwhile, in acidic media, Fe–N–C_HS shows the best ORR performance with the highest onset potential and limiting current. This highly porous Fe–N–C_HS catalyst also demonstrated active site activation and excellent stability compared with the other samples as well as commercial Pt/C in acidic electrolyte, which suggests its potential for application in proton exchange membrane fuel cells (PEMFCs).

No abstract

No abstract