Our research focus is on designing and creating new kinds of nanomaterials that incorporate a wide variety of elements that impact major challenges in sustainability and in energy. A primary focus of this is understanding how to mix elements with distinct properties across the periodic table. Most syntheses for alloy metal nanoparticles require high temperatures, organic solvents, and removal of oxygen.
Our synthesis works in mild conditions in water and on the benchtop with mild heating. Our future research will focus on exploring the generalizability of this strategy, to incorporate multiple elements into alloy nanoparticles, while also controlling their size and their shape. These are crucial for unlocking new properties.
To begin, place a clean 25.4 millimeter PTFE stir bar into a clean 250 milliliter round bottom flask. Add 58.56 milliliters of ultrapure water into the flask. Place the flask on a 120 volt heating mantle placed on a stir plate.
Set the attached heat controller of the assembled heating mantle to 138 degrees Celsius with stirring at 640 RPM. Attach a condenser to the top of the round bottom flask. Secure it onto a stand.
Then turn on the water flow through the condenser. When the water boils at 100 degrees Celsius and the reaction is at reflux, briefly remove the condenser and directly pipette 1.2 milliliters of the 10 millimolar chloro auric acid solution into the water. Reattach the condenser and allow the reaction to return to reflux, then detach the condenser.
Quickly inject 480 microliters of 100 millimolar trisodium citrate solution in a single addition. Immediately place the condenser back on the flask before allowing the solution to reflux. After eight minutes, remove the flask from the heating mantle.
To begin, transfer six milliliters of gold seeds with the corresponding volume of ultrapure water into a 20 milliliter glass scintillation vial. Place a 12.7 millimeter PTFE stir bar into the vial. Place the vial on a stir plate.
Then initiate stirring at a speed of 1, 500 RPM. Next, add an appropriate amount of 10%Polyvinylpyrrolidone into the reaction vial. Then add the corresponding volume of the five millimolar static chloride solution to the vial.
Remove the vial from the stir plate, seal the reaction vial tightly, and immerse it in a hot water bath at 60 degrees Celsius. After 10 minutes, extract the vial from the hot water bath, uncap the vial, and reposition it onto the stir plate. Add 2.03 milliliters of ultra pure water into a vial containing solid sodium borohydride.
After securing the cap, agitate the mixture until the salt dissolves. Immediately pipette the sodium borohydride solution into the reaction vial in a quick injection, continue to stir the reaction mixture for 30 seconds. Remove the reaction vial from the stir plate.
Place the loosely capped vial in the hot water bath at 60 degrees Celsius for 20 minutes. Finally, remove the vial from the hot water bath, then cool to room temperature.
