A study on the effect of selected process parameters in a jet diffusion flame for Pt nanoparticle formation

Pt is used in many catalytic applications from three-way catalysts to fuel cells. Particle size and morphology are key parameters that influence the electrocatalytic activity. Flame synthesis is an efficient and continuous manufacturing route capable of producing Pt nanoparticles with desirable catalytic properties. In order to understand the effect of the forced oxidant, solvent composition, and quench rate on nanoparticle formation, a systematic study of process parameters using Pt was undertaken. Reactive spray deposition technology was used as the synthesis platform. In order to obtain a tight control of the Pt size, it was found that the fuel must contain a sufficient enthalpy of combustion and appropriate propane content. The fuel must be mixed adequately to form a turbulent diffusion flame and must create conditions where unwanted Pt coarsening cannot occur. From this study, the conditions that favor this morphology require an O₂ flow rate setting of 6.89 L/min or higher, a propane content of 20 wt%, and no quenching. Electrochemical data show decreasing electrochemical surface area (75–36 m²/g_Pt), increasing mass activity (120–610 mA/mg_Pt), and increasing specific activity (150–1350 \( \upmu {\text{A}}/ {\text{cm}}^{2} {_{\text{Pt}}} \)) with increasing oxidant flow.