Seminars Archive

Fundamental investigation of the surface reactivity of CoCrFeNi high entropy alloy

Ye Xu
Louisiana State University - USA

Abstract
High entropy alloys (HEAs) represent a huge material space in which to discover new mechanical, magnetic, electronic, and chemical properties. Recently, research interest in exploring HEAs for catalysis has increased rapidly, but fundamental understanding of the surface reactivity of HEAs lags behind the pace at which they are being tested for the multitude of possible applications. In this talk, I will present recent surface science experiments and computational modeling to shed light on the adsorption of common molecules including hydrogen, oxygen, and carbon monoxide on the equimolar alloy of CoCrFeNi, which can catalyze the hydrogen evolution reaction (HER) in an acidic solution with a moderate overpotential vs. Pt. The vibration of these species is studied with high-resolution electron energy loss spectroscopy on a single-crystal (110) surface of the HEA. The interpretation of key vibrational features are critically aided by first-principles DFT calculations. Moreover, DFT-based theoretical modeling is used to predict the HER activity of the low-index facets of the HEA with coverage effects and different hydrogen states taken into consideration. Our research explores the potential of this HEA as a technologically important catalytic material.