Our work in the Nano Engineering Lab in Department of Mechanical and Industrial Engineering at UIC is related to ultra-small nanoparticles that form on the surface of carbon supports. There are many applications where we need to use carbon substrate with metal particles. Carbon is a very reliable choice for environmental control remediations – such as water filtration, capacitive deionization, and pollutant removals – and works as a very good support or substrate for catalyst applications or energy storage. For the industrial applications of metal-decorated carbon supports, we desire that the particles stay intact and do not clump together during the service condition when exposed to complex-reactive environment such as temperature, moisture, or gas reactions.
In our research reported in Nature Communications, we performed real-time imaging to visualize how metal particles anchor to carbon supports. A key part of the investigation was taking a step back to understand how the metal particles form on the surface of carbon. We knew that with some high temperature processing or chemical processing, that metal particles can form on the surface of carbon. However, no one has really looked at the nanometer scale or submicron scale to see how these things form.
By conducting a visualization of this process inside an atomic-resolution electron microscope, we were able to see what happens to the carbon substrate when these particles nucleate and grow, and we investigated the mechanism for the formation of these particle. My team led by Zhennan Huang, a PhD student at UIC, explained how metal particles remain stable on the surface of carbon, and understand why they don't agglomerate together. We discovered that the transformation of disordered carbon to highly ordered carbon plays a significant role in anchoring the metal particles at graphitic edges, and prevents coalescence.
This breakthrough has the potential to make a considerable impact on the catalysis industry. It may enhance the durability of catalysts that are critical for speeding up the chemical reactions – such as making synthesis gas, ammonia, cracking of gas oil – impacting the oil or petroleum industry. In addition, this study may facilitate the application of carbon-decorated metallic particles for water filtration, water disinfection, or the removal of pollutants from water. Other research fields that can benefit from this work could be energy storage devices such as lithium-air batteries or supercapacitors.
We were very fortunate to collaborate with excellent researchers and students from University of Maryland, College Park, Argonne National Laboratory, Northwestern University, and Yanshan University in China.