Synthesis of Nanocomposites

About

Industry Problem: Platinum (Pt)-based nanoparticles are widely used as efficient catalysts in fuel cells and other electrochemical systems. However, the high cost and poor stability of Pt under harsh alkaline or acidic conditions has led to the search for alternative efficient and cost-effective electro catalysts with low Pt loading. Technology Solution: Researchers at the University of Tennessee have developed an inexpensive, one-step, one-pot method to synthesize complex and highly stable nanoalloys (NAs) and nanocomposites (NCs) with superior catalytic activities. This novel method uses pulsed laser ablation synthesis in solution in tandem with galvanic replacement reactions to synthesize intermetallic NAs/NCs as efficient fuel cell electro catalysts. This “green” method does not involve wet chemical routes that require harsh chemicals such as surfactants or stabilizing agents, which are also potentially harmful for surface catalytic activities. Recent results for NCs comprising PtCo NAs indicate a combined overpotential of 756 mV for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media, which is the best value ever reported for catalysts supported by carbon black. Moreover, a post-treatment acid wash allows synthesis of pure PtCo NAs that exhibit a six-fold increase in ORR specific activities in comparison with commercial Pt/C, while enabling 20–25% reduction (atomic weight) in precious Pt loading. Benefits: ·         Rapid, cost effective, and “green” ·         Ability to tailor and control morphology, size, and composition/alloying ·         Does not use harsh surfactants or reducing agents ·         Stable under acidic and alkaline conditions ·         Highly competitive electro catalytic materials indicating: ·         ORR mass activity ~ 0.32 A/mg of Pt ·         20–25% reduction in Pt loading (at. wt.) Applications: ·         Electro catalysts ·         Fuel cells ·         Optics