Dual-doped graphene/perovskite bifunctional catalysts and the oxygen reduction reaction

- First report of dual-doped graphene/perovskite catalysts for the oxygen reduction
- Addition of LSM improves catalytic activity by favouring the 4e direct pathway.
- Composition of graphene derivative/LSM is optimised at 80:20 ratio.
- Sulphur-nitrogen doped-graphene/LSM shows the lowest peroxide production.
- Phosphorus-nitrogen doped graphene/LSM gives lowest overpotential.

We report the first investigation of dual-doped graphene/perovskite mixtures as catalysts for oxygen reduction. Pairwise combinations of boron, nitrogen, phosphorus and sulfur precursors were co-reduced with graphene oxide and mixed with La0.8Sr0.2MnO3 (LSM) to produce SN-Gr/LSM, PN-Gr/LSM and BN-Gr/LSM catalysts. In addition, the dual-doped graphenes, graphene, LSM, and commercial Pt/C were used as controls. The addition of LSM to the dual-doped graphenes significantly improved their catalytic performance, with optimised composition ratios enabling PN-Gr/LSM to achieve 85% of the current density of commercial Pt/C at − 0.6 V (vs. Ag/AgCl) at the same loading. The effective number of electrons increased to ca. 3.8, and kinetic analysis confirms the direct 4 electron pathway is favoured over the stepwise (2e + 2e) route: the rate of peroxide production was also found to be lowered by the addition of LSM to less than 10%.

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