Two graduate students will present their research at the next Beckman Institute Graduate Student Seminar: Rachel Nixon, chemistry; and Hao (Alvin) Yang, materials science and engineering. The event will take place at noon Wednesday, Dec. 6 in 5602 Beckman Institute.
Register to attend and receive lunch.
"Synergistic effects between plasmonic activation and electrochemistry for sustainable fuel synthesis"
Plasmonic chemistry offers a unique way to synthesize critical chemicals and fuels in a manner that is more sustainable than current industrial methods by using light as a renewable energy source and working under ambient conditions. In this approach, metallic nanoparticles are irradiated with a certain frequency of light. The nanoparticles act as antennas, absorbing energy from the light and converting it into energetic charge carriers which catalyze reactions involving molecules that are absorbed to the nanoparticle surfaces. Although thermodynamics limits the types of reactions achievable through plasmonic excitation, applying an electrical bias allows virtually all possible redox reactions to be accessible by the plasmonic reaction system. This combination of plasmonic excitation and applied electrical bias can therefore lead to synergistic enhancements in the yield rate and selectivity of a reaction. We have demonstrated such effects during the reduction of nitrate, a common surface water pollutant, to ammonia, a component of fertilizer and promising carbon-free fuel. We have found that incorporating plasmonic excitation during the electrochemical synthesis of ammonia increases yield rate by 15X compared to that achieved under equivalent dark conditions.1 This demonstration could lead the way toward greener manufacturing of other commodity chemicals powered by renewable electricity and light.
Rachel Nixon is a fourth-year Ph.D. student in the Department of Chemistry working under the guidance of Professor Prashant K. Jain. Her research focuses on utilizing plasmonic nanomaterials, which harvest energy from light, in combination with electrical bias for catalyzing fuel-forming reactions. Her work is supported by the Link Foundation Energy Fellowship.
"Designing bioelectronic materials using heme-containing peptides"
Electron transport in proteins serves as a biological “power line” that fuels cellular activities such as respiration and photosynthesis. Within cells, proteins act as conduits, shuttling electrons through a series of reactions and pathways to generate proton gradients and to drive ATP synthesis. In this talk, we explore the possibility of using biological building blocks such as proteins as functional components for next-generation electronic devices. We study heme-containing proteins commonly found in biology, such as those in human blood. A broad class of heme-containing proteins have remarkable abilities to transport electrons. Our work aims to harness these properties by designing and building engineered peptide-heme constructs for bioelectronic applications. Following materials design and synthesis, we characterize the electron transport properties of these materials using cutting-edge methods in molecular electronics. Our approach relies on creating self- assembled monolayers (SAMs) using sequenced-defined peptides with heme-binding capacities. Current density (I-V curves) is directly measured in peptide monolayers using a liquid metal soft contact electrode method known as the EGaIn method (eutectic gallium indium alloy). EGaIn current density measurements reveal a staggering 1000-fold increase in current density across the junction upon heme loading while maintaining constant film thickness. Using optical spectroscopy and circular dichroism spectroscopy, we further validate the formation of peptide secondary structures and confirm successful heme integration. Robust monolayer formation is further characterized using atomic force microscopy, ellipsometry, and X-ray photoelectron spectroscopy. Overall, our work showcases the potential of using engineered peptides and heme-based materials as next-generation electronic devices.
Hao Yang, a fourth-year Ph.D. student in the Department of Materials Science and Engineering, is mentored by Professor Charles M. Schroeder. His research focuses on molecular charge transport by understanding how electrons move across single molecules and self-assembled monolayers to uncover the connection between molecular structure and electronic functionality. He completed his undergraduate studies in chemical engineering at the University of California, Santa Barbara. Apart from his research, he's a passionate coffee enthusiast who skillfully crafts specialty coffee with an exceptional touch.
Learn more about Beckman's Graduate Student Seminar Series.
Read Q&As with student researchers on Beckman's Student Researcher Spotlight page.
