Research Interests: Renewable chemical manufacturing, process optimization, materials development & characterization
A lot of modern industries rely heavily on petrochemical feedstocks, which contribute to global warming due to the uncontrolled emission of greenhouse gases. However, there’s an opportunity to shift toward more sustainable sources. Agricultural waste provides large volumes of lignocellulosic biomass—an abundant and renewable alternative to petrochemicals. This waste biomass can be broken down into smaller compounds known as platform molecules. These serve as versatile starting points for synthesizing a wide variety of value-added chemicals. Many of these platform molecules contain carbon–carbon, carbon–oxygen (C–O), and carbon–hydrogen (C–H) bonds, which makes them well-suited for oxidative coupling reactions—a powerful route to produce esters and other high-value products. Au is well known to be a selective metal for such oxidations, though its behavior can be sensitive to alloying with highly active dopant metals such as Pd, Pt, Ni, and Rh. A subclass of these alloys, termed single-atom alloys (SAAs), possesses dopant atoms that are fully isolated from one another, creating unique electronic and geometric environments that break traditional scaling relationships and limit over-binding. My research has focused on two Au-based dilute-limit alloys doped with Pd (PdAu) and Rh (RhAu) to better understand how C–H, O–H, and C–O bond activations can be manipulated in selective oxidations over Au, and how sensitive these behaviors are to the bulk and local compositions of these dopants. Catalytic studies reveal that Rh1Aux promotes ethanol oxidation but with different selectivity than Pd1Aux systems. While Pd favors oxidative coupling to yield ethyl acetate, increasing Rh content shifts selectivity toward acetaldehyde. This is attributed to differences in ethoxy stabilization versus decomposition: Pd promotes coupling by stabilizing ethoxy species, allowing for facile coupling with acetaldehyde, while Rh stabilizes ethoxy species to a greater extent and triggers comparatively rapid C–H activation, leading to acetaldehyde formation and low ethoxy surface coverages. These findings show that using different dopants enables tunable control over product distributions, offering design strategies for optimizing activity and selectivity in partial oxidation reactions.
