Chidziva, StanfordBai, YimingSang, Chengcheng2026-02-162026-02-162026Bai, Y., Sang, C., Luo, Z., Huang, R., Zhang, Z., Yin, Y., Lu, J., Xu, H., Huang, Y., Gao, W. and Liu, X., 2025. Simple, rapid, scalable confined synthesis of ultrafine Pt nanoclusters for fuel cells. Journal of Energy Chemistry.https://doi.org/10.1016/j.jechem.2025.11.042https://hdl.handle.net/10566/21972Small-sized nanoclusters exhibit catalytic activity in electrochemical reactions distinct from the bulk-like properties of nanoparticles 2 nm or larger, yet their surfactant-free synthesis remains a formidable challenge. A scalable microchannel-confined synthesis method enables rapid, controlled formation of 1.12 nm Pt nanoclusters without additional surfactants. Kinetic control achieves a nucleation and growth time of approximately 18.6 s, with heat transfer simulations confirming uniform temperature attainment within 0.5 s. Half-cell and single-cell tests, corroborated by density functional theory (DFT) calculations, demonstrate exceptional performance of these Pt nanoclusters in proton exchange membrane fuel cell (PEMFC), achieving a mass activity 1.9 times that of commercial samples and a rated power density of 1.55 W cm−2. This method can employ multiple capillaries assembled into a capillary bundle to enable parallel experiments, highlighting its scalability and potential to advance hydrogen-electricity conversion technologies.enConfined synthesisFlow synthesisOxygen reduction reactionPEMFCPt nanoclusterArticle