High-temperature annealing often induces severe sintering of Pt nanoparticles in Pt/C catalysts, resulting in activity degradation. Here, a carbon nitride–assisted thermal treatment strategy is proposed to enhance the thermal stability of Pt/C. TG-FTIR and XPS analysis reveal that nitrogen-containing species generated during carbon nitride decomposition play a key role in suppressing Pt nanoparticle coalescence at intermediate temperatures. Although the carbon nitride framework decomposes at high temperatures, residual graphitic and pyridinic nitrogen species are retained and interact electronically with Pt, leading to a reduced Pt binding energy. As a result, the carbon nitride–assisted Pt/C maintains a narrow particle size distribution after annealing. Electrochemical measurements demonstrate that the assisted catalyst retains oxygen reduction reaction activity comparable to commercial Pt/C after thermal treatment at 700 °C, while the untreated sample shows pronounced performance loss. Moreover, the assisted catalyst exhibits significantly improved durability after 20 000 cycles. This work offers a simple and effective approach to improving the thermal robustness of Pt-based electrocatalysts for PEM fuel cells.
Li et al. (Mon,) studied this question.