Fe Ions-Doped TiO₂ Aerogels as Catalysts of Oxygen Reduction Reactions in Alkaline Solutions

Aerogels have interconnected networks and preeminent pore structures. When used as the catalysts for oxygen reduction reaction (ORR), they can facilitate the mass transfer and expose more active sites. Here, we synthesized the Fe-doped titanium oxide-based aerogels (TA/Fes) by the sol–gel method combined with thermal treatment. The specific surface areas of the TA/Fes ranged from 475 to 774 m²·g⁻¹, and the pore volumes varied from 0.96 to 1.72 cm³·g⁻¹. The doping effect of the Fe ions and the oxygen vacancies in anatase enhance the electrical conductivity, leading to the low Rct (313.3–828.2 Ω). All samples showed excellent stability (2.0–4.5 mV) and 4e⁻ pathway. The limiting current density of TA/Fe3 reached 5.34 mA·cm⁻², which was comparable to that of commercial Pt/C. The preparation method is inspiring and the as-prepared aerogel catalysts have potential in promoting the scale of fuel cells.