Zili Wu, Leader of the Surface Chemistry & Catalysis Group
Oak Ridge National Laboratory (ORNL)

Insights from Neutron Scattering into the Catalytic Roles of Surface and Lattice Hydrides in Heterogeneous Catalysis 
 

ABSTRACT: Different from X-ray scatting, neutron scattering is uniquely powerful in detecting light elements such as hydrogen and oxygen. These elements are often involved in catalysis either as surface species, intermediates, spectators, or in the catalyst bulk. Detecting and understanding the nature and structure of these species in catalysis is significant but often is difficult with regular techniques. However, compared to X-ray techniques, neutron scattering has shown rather limited applications in catalysis research using, mostly due to the scarce neutron sources, low beam intensity, long collection time, low sensitivity and resolution, and large amount of sample needed. 
With the commission of the spallation neutron source (SNS) at Oak Ridge National Laboratory, a more intense, brighter source of neutrons and world-class instrumentations have become available to the scientific community to carry out neutron measurements with greater sensitivity, faster speed, higher resolution, and in more complex sample environments. We have recently taken advantage of SNS instruments to study a few hydrogen-involved reactions including selective hydrogenation of acetylene, CO2, ammonia synthesis, and preferential oxidation of CO. I will present in this talk the unique insights into catalysis including surface species, catalytic structures and reaction mechanisms obtained from neutron spectroscopy and diffraction, in combination with X-ray absorption spectroscopy, optical spectroscopy, and electron microscopy.   New applications are expected to continue to emerge for neutron scattering investigations of heterogeneous catalysis.
This research is sponsored by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Catalysis Science program. The neutron studies used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Part of the work including electron microscopy tests was conducted at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility.
 

BIO: Dr. Zili Wu is a Distinguished R&D Staff Member and Leader of the Surface Chemistry and Catalysis Group (https://www.ornl.gov/division/csd/surface-chemistry)  in the Chemical Sciences Division at Oak Ridge National Laboratory (ORNL). He serves as Director of the DOE Energy Earthshots Research Center (EERC), Non-equilibrium Energy Transfer for Efficient Reactions (NEETER), and as a Thrust Leader in UNCAGE-ME, one of DOE’s Energy Frontier Research Centers (EFRCs).

Dr. Wu earned his Ph.D. in physical chemistry from the Dalian Institute of Chemical Physics in 2001. During his doctoral studies, he spent one year at the Institute of Catalysis and Petrochemistry in Madrid, Spain. He then spent more than three years at Northwestern University as a postdoctoral associate before joining the staff at ORNL in 2006.

Dr. Wu has extensive expertise in heterogeneous catalysis, applied spectroscopy, and nanomaterials synthesis. His research focuses on developing a fundamental understanding of catalytic active sites at surfaces and interfaces in heterogeneous catalysis, photocatalysis, and electrocatalysis; establishing structure-catalysis relationships in catalytic solids across time and length scales; applying in situ and operando characterization methods; and designing nanomaterials with well-defined structures.

He is an active member of the American Chemical Society and has organized more than 15 ACS symposia on fundamental catalysis and energy materials. His recent honors include the 2023 ORNL Outstanding Research Output Team Award, the 2020 ORNL-CNMS Outstanding Scientific and Technological Accomplishment Award, and the 2019 Excellence in Catalysis Award from the Catalysis Society of Metropolitan New York.