Urea-treated Ti3C2Tz MXene for improved oxygen reduction reaction in alkaline fuel cells

Commercial fuel cell catalysts are usually based on platinum, which has cost and stability issues. Alkaline fuel cells are attractive, as alkaline media provides better oxygen reduction reaction (ORR) kinetics and allows for a wider range of materials to be used. MXenes have shown interesting properties in electrochemical applications, but they can suffer from drawbacks, including small surface areas in comparison with other catalyst supports. In this work, we use urea and thermal treatments to intercalate carbon and nitrogen species in Ti3C2Tz (where Tz stands for surface terminations), enlarging the interlayer spacing and increasing the materials’ surface area. The materials are tested for their ORR performance, and it is shown that the introduction of N–C species from the urea decomposition greatly increases the performance in comparison with bare Ti3C2. These materials can serve as more affordable alternatives to Pt/C, lowering the overall cost of fuel cells. • Urea intercalated on MXenes increases surface area and deposits C and N species within the MXene layers. • The materials show promising performance when tested as electrocatalysts for oxygen reduction in alkaline fuel cells. • Ti 3 C 2 –U50-800 shows a high onset potential (0.88 V vs SHE) and a shift of 10 mV in half-wave potential after 2000 cycles.