Wheat ear-like catalysts were prepared on Co–OH–CO₃ nanowires to design an ultra-thin catalyst layer (UTCL). Without any ionomers, the UTCL exhibited a maximum power density of 481 mW cm⁻² at an ultra-low Pt loading of 43 μg cm⁻²_Pt, resulting in a relatively high Pt utilization of 11.2 kW g⁻¹_Pt. It is expected that the nanostructured thin film materials will lead to further technological advancements in fuel cells and other applications.