High-Pressure Continuous-Flow Synthesis of Carbon-Supported PtCo Nanoparticles for Oxygen Reduction Catalysis

Proton exchange membrane fuel cells (PEMFCs) rely on high-performance Pt-based ORR catalysts, but traditional high-pressure hydrothermal batch synthesis suffers from low scalability and batch inconsistency. Herein, we report a high-pressure continuous-flow reactor enabling scalable synthesis of carbon-supported PtCo nanoparticles (PtCo/C) under hydrothermal conditions (270 °C, 5   MPa), achieving a production rate of 400   mg   h -1 . Subsequent annealing induces the formation of an L1 2 ordered structure in PtCo/C-CPA, which exhibits enhanced metallic Pt/Co ratios and optimized electronic properties. Electrochemical measurements showed that PtCo/C-CPA achieves a mass activity (MA) of 0.547   A   mg -1 at 0.9   V (vs. RHE), which is 3.38 times higher than that of commercial Pt/C for oxygen reduction reaction (ORR). After 30,000 cycles, the catalyst still retained 75.1% of its initial MA. This strategy integrates high-pressure quality and continuous-flow scalability, offering a robust pathway for industrializing high-performance ORR catalysts.