CAS: Improving the Efficiency of Supported Palladium Catalysts for Methane Complete Combustion Using Monodisperse Nanocrystals

Stanford University, Stanford CA

Investigators

Abstract

Developing catalysts for the complete oxidation of methane is important to avoid emissions of this powerful greenhouse gas while taking advantage of it as an energy resource. Recent studies show that removing methane from the atmosphere could reduce greenhouse gas potential to pre-industrial levels, thus resulting in atmospheric restoration. Currently, palladium is the best metal to perform this reaction, but it is not well understood how to improve its activity to make better use of this expensive metal. In this project, Dr. Cargnello of Stanford University is developing an understanding of how palladium activates the C-H bonds in methane and oxidizes it completely to carbon dioxide and water. Using precisely controlled catalytic materials prepared from colloidal nanocrystals, Dr. Cargnello is uncovering novel details about the catalytic behavior of palladium and its optimal utilization. Dr. Cargnello is actively engaged in efforts to increase diversity in the Stanford School of Engineering through research experiences with undergraduates, high-school students, and teachers from diverse backgrounds. These activities, which include trips to high schools to inform younger students about STEM and chemical engineering opportunities, have the goal to encourage diverse students to consider careers in these fields. With funding from the Chemical Catalysis Program of the Division of Chemistry, Dr. Cargnello of Stanford University is developing a fundamental understanding of the chemistry of supported palladium in the catalytic total methane combustion. Efficient use of palladium catalysts will help to decrease emissions of this powerful greenhouse gas. Many questions related to the complex palladium oxidation state chemistry as a function of reaction conditions, its correlation with support materials, the presence of promoters, and catalyst stability at high temperature and in the presence of water remain debated. All these aspects are key to fully understand catalyst behavior, and to find ways to further increase Pd efficiency and utilization. The use of precise nanocrystals as building blocks of uniform catalysts is a key focus in this project in order to identify Pd active phase, oxidation state, and structure under relevant reaction conditions; understand Pd deactivation; and how promoting phases change the structure and oxidation state of Pd. The catalytic studies are supported by collaborative efforts using in-situ and operando spectroscopy and DFT calculations in collaboration with staff scientists at SLAC National Laboratory. Dr. Cargnello is actively engaged in efforts to increase diversity in the School of Engineering and inform younger generations about STEM and chemical engineering opportunities, to encourage diverse students to consider a career in the science and engineering fields. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.